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Sample records for 111-oriented bfo films

  1. Highly (111)-oriented multiferroic BiFeO3 thin film on a glass substrate

    NASA Astrophysics Data System (ADS)

    Maeng, W. J.; Son, J. Y.

    2013-03-01

    BiFeO3 (BFO) thin films were deposited on Pt/Ta/glass substrates by pulsed laser deposition. To grow highly (111)-oriented and good adhesive Pt bottom electrodes, Ta adhesion layers were used between Pt bottom electrodes and glass substrates. On the highly (111)-oriented Pt bottom electrodes, highly (111)-oriented polycrystalline BFO thin films were obtained as confirmed by X-ray diffraction experiments. The BFO thin film exhibited a high ferroelectric polarization (2Pr≈56 μC/cm2). The highly (111)-oriented BFO thin film also showed a ferromagnetic hysteresis loop and a ferroelectric domain size of approximately 30-40 nm, which is equivalent to 0.25 Tbit/in2.

  2. Structural and pyroelectric properties of sol-gel derived multiferroic BFO thin films

    SciTech Connect

    Jo, Seo-Hyeon; Lee, Sung-Gap; Lee, Seung-Hwan

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We fabricated multiferroic BFO/PZT multilayer films by spin-coating method. Black-Right-Pointing-Pointer The trap centers of carriers were formed at the interfaces between BFO and PZT films. Black-Right-Pointing-Pointer The ferroelectric properties were superior to those of single composition BFO film. -- Abstract: Multiferroic BFO/PZT multilayer films were fabricated by spin-coating method on the (1 1 1)Pt/Ti/SiO{sub 2}/Si substrate alternately using PZT(30/70), PZT(70/30) and BFO alkoxide solutions. The structural and ferroelectric properties were investigated for uncooled infrared detector applications. The coating and heating procedure was repeated six times to form BFO/PZT multilayer films. All films showed the typical XRD patterns of the perovskite polycrystalline structure without presence of the second phase such as Bi{sub 2}Fe{sub 4}O{sub 3}. The thickness of BFO/PZT multilayer film was about 200-220 nm. The ferroelectric properties such as dielectric constant, remnant polarization and pyroelectric coefficient were superior to those of single composition BFO film, and those values for BFO/PZT(70/30) multilayer film were 288, 15.7 {mu}C/cm{sup 2} and 9.1 Multiplication-Sign 10{sup -9} C/cm{sup 2} K at room temperature, respectively. Leakage current density of the BFO/PZT(30/70) multilayer film was 3.3 Multiplication-Sign 10{sup -9} A/cm{sup 2} at 150 kV/cm. The figures of merit, F{sub V} for the voltage responsivity and F{sub D} for the specific detectivity, of the BFO/PZT(70/30) multilayer film were 6.17 Multiplication-Sign 10{sup -11} Ccm/J and 6.45 Multiplication-Sign 10{sup -9} Ccm/J, respectively.

  3. Superconducting thin films of (100) and (111) oriented indium doped topological crystalline insulator SnTe

    SciTech Connect

    Si, W.; Zhang, C.; Wu, L.; Ozaki, T.; Gu, G.; Li, Q.

    2015-09-01

    Recent discovery of the topological crystalline insulator SnTe has triggered a search for topological superconductors, which have potential application to topological quantum computing. The present work reports on the superconducting properties of indium doped SnTe thin films. The (100) and (111) oriented thin films were epitaxially grown by pulsed-laser deposition on (100) and (111) BaF2 crystalline substrates respectively. The onset superconducting transition temperatures are about 3.8 K for (100) and 3.6 K for (111) orientations, slightly lower than that of the bulk. Magneto-resistive measurements indicate that these thin films may have upper critical fields higher than that of the bulk. With large surface-to-bulk ratio, superconducting indium doped SnTe thin films provide a rich platform for the study of topological superconductivity and potential device applications based on topological superconductors.

  4. Superconducting thin films of (100) and (111) oriented indium doped topological crystalline insulator SnTe

    DOE PAGESBeta

    Si, W.; Zhang, C.; Wu, L.; Ozaki, T.; Gu, G.; Li, Q.

    2015-09-01

    Recent discovery of the topological crystalline insulator SnTe has triggered a search for topological superconductors, which have potential application to topological quantum computing. The present work reports on the superconducting properties of indium doped SnTe thin films. The (100) and (111) oriented thin films were epitaxially grown by pulsed-laser deposition on (100) and (111) BaF2 crystalline substrates respectively. The onset superconducting transition temperatures are about 3.8 K for (100) and 3.6 K for (111) orientations, slightly lower than that of the bulk. Magneto-resistive measurements indicate that these thin films may have upper critical fields higher than that of the bulk.more » With large surface-to-bulk ratio, superconducting indium doped SnTe thin films provide a rich platform for the study of topological superconductivity and potential device applications based on topological superconductors.« less

  5. Superconducting thin films of (100) and (111) oriented indium doped topological crystalline insulator SnTe

    SciTech Connect

    Si, Weidong E-mail: qiangli@bnl.gov; Zhang, Cheng; Wu, Lijun; Ozaki, Toshinori; Gu, Genda; Li, Qiang E-mail: qiangli@bnl.gov

    2015-08-31

    Recent discovery of the topological crystalline insulator SnTe has triggered a search for topological superconductors, which have potential application to topological quantum computing. The present work reports on the superconducting properties of indium doped SnTe thin films. The (100) and (111) oriented thin films were epitaxially grown by pulsed-laser deposition on (100) and (111) BaF{sub 2} crystalline substrates, respectively. The onset superconducting transition temperatures are about 3.8 K for (100) and 3.6 K for (111) orientations, slightly lower than that of the bulk. Magneto-resistive measurements indicate that these thin films may have upper critical fields higher than that of the bulk. With large surface-to-bulk ratio, superconducting indium doped SnTe thin films provide a rich platform for the study of topological superconductivity and potential device applications based on topological superconductors.

  6. Epitaxial Structure of (001)- and (111)-Oriented Perovskite Ferrate Films Grown by Pulsed-Laser Deposition.

    PubMed

    Chakraverty, Suvankar; Ohtomo, Akira; Okude, Masaki; Ueno, Kazunori; Kawasaki, Masashi

    2010-04-01

    The epitaxial structures of SrFeO(2.5) films grown on SrTiO(3) (001) and (111) substrates by PLD are reported. A layer-by-layer growth mode was achieved in the initial stage on both substrates. The films were stabilized with a monoclinic structure, where we identified the in-plane domain structures and orientation relationship. Our study presents a guide to control the heteroepitaxy of (111)-oriented noncubic perovskites. PMID:20383295

  7. Ferroelectric properties of PZT/BFO multilayer thin films prepared using the sol-gel method

    PubMed Central

    2012-01-01

    In this study, Pb(Zr0.52Ti0.48)O3/BiFeO3 [PZT/BFO] multilayer thin films were fabricated using the spin-coating method on a Pt(200 nm)/Ti(10 nm)/SiO2(100 nm)/p-Si(100) substrate alternately using BFO and PZT metal alkoxide solutions. The coating-and-heating procedure was repeated several times to form the multilayer thin films. All PZT/BFO multilayer thin films show a void-free, uniform grain structure without the presence of rosette structures. The relative dielectric constant and dielectric loss of the six-coated PZT/BFO [PZT/BFO-6] thin film were approximately 405 and 0.03%, respectively. As the number of coatings increased, the remanent polarization and coercive field increased. The values for the BFO-6 multilayer thin film were 41.3 C/cm2 and 15.1 MV/cm, respectively. The leakage current density of the BFO-6 multilayer thin film at 5 V was 2.52 × 10-7 A/cm2. PMID:22221519

  8. Giant isothermal entropy change In (111)-oriented PMN-PT thin film

    NASA Astrophysics Data System (ADS)

    Hamad, Mahmoud A.

    2014-11-01

    An isothermal entropy change of 240 nm (111)-oriented PMN-PT 65/35 film near the ferroelectric Curie temperature, relative cooling power (RCP) and change of heat capacity have been investigated. The extracted data characterized giant isothermal entropy change of more than 16 J/kg K in electric field shift ΔE of 455 kV cm-1, which is nearly twice than that found for PbZr0.95Ti0.05O3 thin film at 492 kV cm-1 near the Curie point. Furthermore, the RCP ≈ 700 J/kg and change of heat capacity ≈ 233 J/kg K in electric field shift ΔE of 747 kV cm-1.

  9. Formation of (111) orientation-controlled ferroelectric orthorhombic HfO2 thin films from solid phase via annealing

    NASA Astrophysics Data System (ADS)

    Mimura, Takanori; Katayama, Kiliha; Shimizu, Takao; Uchida, Hiroshi; Kiguchi, Takanori; Akama, Akihiro; Konno, Toyohiko J.; Sakata, Osami; Funakubo, Hiroshi

    2016-08-01

    0.07YO1.5-0.93HfO2 (YHO7) films were prepared on various substrates by pulse laser deposition at room temperature and subsequent heat treatment to enable a solid phase reaction. (111)-oriented 10 wt. % Sn-doped In2O3(ITO)//(111) yttria-stabilized zirconia, (111)Pt/TiOx/SiO2/(001)Si substrates, and (111)ITO/(111)Pt/TiOx/SiO2/(001)Si substrates were employed for film growth. In this study, X-ray diffraction measurements including θ-2θ measurements, reciprocal space mappings, and pole figure measurements were used to study the films. The film on (111)ITO//(111)yttria-stabilized zirconia was an (111)-orientated epitaxial film with ferroelectric orthorhombic phase; the film on (111)ITO/(111)Pt/TiOx/SiO2/(001)Si was an (111)-oriented uniaxial textured film with ferroelectric orthorhombic phase; and no preferred orientation was observed for the film on the (111)Pt/TiOx/SiO2/(001)Si substrate, which does not contain ITO. Polarization-hysteresis measurements confirmed that the films on ITO covered substrates had saturated ferroelectric hysteresis loops. A remanent polarization (Pr) of 9.6 and 10.8 μC/cm2 and coercive fields (Ec) of 1.9 and 2.0 MV/cm were obtained for the (111)-oriented epitaxial and uniaxial textured YHO7 films, respectively. These results demonstrate that the (111)-oriented ITO bottom electrodes play a key role in controlling the orientation and ferroelectricity of the phase formation of the solid films deposited at room temperature.

  10. Refractive index dispersion of swift heavy ion irradiated BFO thin films using Surface Plasmon Resonance technique

    NASA Astrophysics Data System (ADS)

    Paliwal, Ayushi; Sharma, Savita; Tomar, Monika; Singh, Fouran; Gupta, Vinay

    2016-07-01

    Swift heavy ion irradiation (SHI) is an effective technique to induce defects for possible modifications in the material properties. There is growing interest in studying the optical properties of multiferroic BiFeO3 (BFO) thin films for optoelectronic applications. In the present work, BFO thin films were prepared by sol-gel spin coating technique and were irradiated using the 15 UD Pelletron accelerator with 100 MeV Au9+ ions at a fluence of 1 × 1012 ions cm-2. The as-grown films became rough and porous on ion irradiation. Surface Plasmon Resonance (SPR) technique has been identified as a highly sensitive and powerful technique for studying the optical properties of a dielectric material. Optical properties of BFO thin films, before and after irradiation were studied using SPR technique in Otto configuration. Refractive index is found to be decreasing from 2.27 to 2.14 on ion irradiation at a wavelength of 633 nm. Refractive index dispersion of BFO thin film (from 405 nm to 633 nm) before and after ion radiation was examined.

  11. Nanoscale bit formation in highly (111)-oriented ferroelectric thin films deposited on glass substrates for high-density storage media

    NASA Astrophysics Data System (ADS)

    Kim, Dae Hong; Kim, Yong Kwan; Hong, Seungbum; Kim, Yunseok; Baik, Sunggi

    2011-06-01

    PbTiO3 (PTO) ferroelectric films on Pt(111) bottom electrode layers covering Ta/glass were prepared using pulsed laser deposition. X-ray diffraction patterns revealed that the PTO films were preferentially (111)-oriented. The films were highly crystalline and had a smooth surface with root mean square (RMS) roughness of 1.5 nm. Ferroelectric properties of the PTO films were characterized using piezoresponse force microscopy (PFM). PFM techniques achieved ferroelectric polarization bits with a minimum width of 22 nm, which corresponds to a potential recording density of 1.3 Tbit/in2 in ferroelectric storage devices.

  12. Nanoscale bit formation in highly (111)-oriented ferroelectric thin films deposited on glass substrates for high-density storage media.

    PubMed

    Kim, Dae Hong; Kim, Yong Kwan; Hong, Seungbum; Kim, Yunseok; Baik, Sunggi

    2011-06-17

    PbTiO(3) (PTO) ferroelectric films on Pt(111) bottom electrode layers covering Ta/glass were prepared using pulsed laser deposition. X-ray diffraction patterns revealed that the PTO films were preferentially (111)-oriented. The films were highly crystalline and had a smooth surface with root mean square (RMS) roughness of 1.5 nm. Ferroelectric properties of the PTO films were characterized using piezoresponse force microscopy (PFM). PFM techniques achieved ferroelectric polarization bits with a minimum width of 22 nm, which corresponds to a potential recording density of 1.3 Tbit/in(2) in ferroelectric storage devices. PMID:21508503

  13. Nanoscale bit formation in highly (111)-oriented ferroelectric thin films deposited on glass substrates for high-density storage media.

    SciTech Connect

    Kim, D. H.; Kim, Y. K.; Hong, S.; Kim, Y.; Baik, S.

    2011-04-21

    PbTiO{sub 3} (PTO) ferroelectric films on Pt(111) bottom electrode layers covering Ta/glass were prepared using pulsed laser deposition. X-ray diffraction patterns revealed that the PTO films were preferentially (111)-oriented. The films were highly crystalline and had a smooth surface with root mean square (RMS) roughness of 1.5 nm. Ferroelectric properties of the PTO films were characterized using piezoresponse force microscopy (PFM). PFM techniques achieved ferroelectric polarization bits with a minimum width of 22 nm, which corresponds to a potential recording density of 1.3 Tbit/in{sup 2} in ferroelectric storage devices.

  14. Effect of post-treatment on photocatalytic oxidation activity of (111) oriented NaNbO3 film

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Wu, Zhou; Sun, Bingyang; Li, Guoqiang; Zhang, Weifeng

    2015-10-01

    We investigate the impact of post-treatment on photocatalytic oxidation activity of (111) oriented NaNbO3 film prepared by pulse laser deposition. Some impurities such as Na2Nb4O11 and bigger particles appear in the treated samples. The activity of rhodamine B degradation with N2 purge increases with the amount of ṡOH, the sample treated under H2/Ar(7%) being the highest activity, followed by under air and untreated one; the opposite trend is observed when the system was without N2 purge.

  15. Enhanced ferroelectric and dielectric properties of (111)-oriented highly cation-ordered PbSc0.5Ta0.5O3 thin films

    NASA Astrophysics Data System (ADS)

    Chopra, Anuj; Birajdar, Balaji I.; Kim, Yunseok; Alexe, Marin; Hesse, Dietrich

    2013-12-01

    Cation-ordered (111)-oriented epitaxial PbSc0.5Ta0.5O3 (PST) thin films were deposited by pulsed laser deposition on SrRuO3-electroded SrTiO3 (111) substrates at three different temperatures of 525 °C, 550 °C, and 575 °C. All the films were well crystalline and (111)-oriented at all the three growth temperatures; however, the films deposited at the temperatures other than 550 °C exhibited the presence of a pyrochlore phase. X-ray diffraction analysis and transmission electron microscopy measurements revealed that the films were epitaxial and highly cation-ordered. In comparison to (001)-oriented PST films, (111)-oriented films on SrRuO3/SrTiO3 (111) exhibited enhanced ferroelectric and dielectric properties with a broad size distribution of cation-ordered domains (5-100 nm). At a measurement temperature of 100 K, the remnant polarization of PST (111) films is almost √3 times larger than the remnant polarization observed for (001)-oriented PST films, which is attributed to the (111) orientation of the films, as the spontaneous polarization in PST lies close to the [111] direction. The observed dielectric constant and loss at 1 kHz were around 1145 and 0.11, respectively. The dielectric constant is thus almost three times higher than for previously reported (001)-oriented PST thin films, most probably due to the enhancement in cation-ordering.

  16. Thin (111) oriented CoFe2O4 and Co3O4 films prepared by decomposition of layered cobaltates

    NASA Astrophysics Data System (ADS)

    Buršík, Josef; Soroka, Miroslav; Uhrecký, Róbert; Kužel, Radomír; Mika, Filip; Huber, Štěpán

    2016-07-01

    The formation and structural characterization of highly (111)-oriented Co3O4 and CoFe2O4 films prepared by a novel procedure from 00l-oriented NaCoO2 and Na(CoFe)O2 is reported. The Na(CoFe)O2 films were deposited on MgO, SrTiO3, LaAlO3, and Zr(Y)O2 single crystals with (100) and (111) orientations by chemical solution deposition method and crystallized at 700 °C. Subsequently they were transformed into (111)-oriented spinel phase during post-growth annealing at 800-1000 °C. Morphology and structure of the films was investigated by means of scanning electron microscopy and X-ray diffraction. While all spinel films exhibit pronounced out-of-plane orientation irrespective of substrate, the rate of in-plane orientation strongly depend on lattice misfit values. Different epitaxial phenomena ranging from true one-to-one epitaxy to the existence of many-to-one epitaxy involving two or more orientations were determined by full 3D texture analysis.

  17. Epitaxial growth of (111)-oriented ZrxTi1-xN thin films on c-plane Al2O3 substrates

    NASA Astrophysics Data System (ADS)

    Li, Ruiteng; Gandhi, Jateen S.; Pillai, Rajeev; Forrest, Rebecca; Starikov, David; Bensaoula, Abdelhak

    2014-10-01

    A systematic study is presented on the effects of process parameters of S-gun configured DC magnetron sputtered ZrN thin films on c-plane Al2O3 substrates. Using a quartz crystal microbalance the deposition rate of ZrN is investigated as a function of Ar and N2 flow rates, target power, chamber pressure and gas injection position in the chamber. Selected growth conditions for ZrN show the interrelation of growth parameters on film orientation and crystallinity. (111) oriented ZrN thin films exhibit X-ray diffraction rocking curve FWHM as low as 0.36°. Additionally, (111) oriented ternary ZrxTi1-xN thin films (0≤x≤1) are also deposited on c-plane Al2O3 substrates. High resolution X-ray diffraction characterization shows that ZrxTi1-xN (x=0, 0.64, 0.80, 0.93, 1) layers exhibit rocking curve FWHM values of 0.0045-0.006° for the (111) reflection, indicating highly crystalline thin films. Atomic force microscopy characterizations show ZrxTi1-xN thin films with a surface roughness between 1.2 nm and 2.9 nm.

  18. Interfacial dislocations in (111) oriented (Ba0.7Sr0.3)TiO3 films on SrTiO3 single crystal

    DOE PAGESBeta

    Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; Kamo, Takafumi; Funakubo, Hiroshi; Wu, Di; Xin, Huolin L.; Su, Dong

    2015-10-08

    In this study, we have investigated the interfacial structure of epitaxial (Ba,Sr)TiO3 films grown on (111)-oriented SrTiO3 single-crystal substrates using transmission electron microscopy (TEM) techniques. Compared with the (100) epitaxial perovskite films, we observe dominant dislocation half-loop with Burgers vectors of a<110> comprised of a misfit dislocation along <112>, and threading dislocations along <110> or <100>. The misfit dislocation with Burgers vector of a <110> can dissociate into two ½ a <110> partial dislocations and one stacking fault. We found the dislocation reactions occur not only between misfit dislocations, but also between threading dislocations. Via three-dimensional electron tomography, we retrievedmore » the configurations of the threading dislocation reactions. The reactions between threading dislocations lead to a more efficient strain relaxation than do the misfit dislocations alone in the near-interface region of the (111)-oriented (Ba0.7Sr0.3)TiO3 films.« less

  19. Broadband dielectric characterization of sapphire/TiOx/Ba₀.₃Sr₀.₇TiO₃ (111)-oriented thin films for the realization of a tunable interdigitated capacitor.

    PubMed

    Ghalem, Areski; Ponchel, Freddy; Remiens, Denis; Legier, Jean-Francois; Lasri, Tuami

    2013-05-01

    A complete microwave characterization up to 67 GHz using specific coplanar waveguides was performed to determine the dielectric properties (permittivity, losses, and tunability) of sapphire/TiOx/Ba0.3Sr0.7TiO3 (BST) (111)-oriented thin films. To that end, BaxSr1-xTiO3 thin films were deposited by RF magnetron sputtering on sapphire (0001) substrate. To control the preferred (111) orientation, a TiOx buffer layer was deposited on sapphire. According to the detailed knowledge of the material properties, it has been possible to conceive, fabricate, and test interdigitated capacitors, the basic element for future microwave tunable applications. Retention of capacitive behavior up to 67 GHz and a tunability of 32% at 67 GHz at an applied voltage of 30 V (150 kV/cm) were observed. The Q-factor remains greater than 30 over the entire frequency band. The possibility of a complete characterization of the material for the realization of high-performance interdigitated capacitors opens the door to microwave device fabrication. PMID:23661122

  20. Vertically Aligned Ge Nanowires on Flexible Plastic Films Synthesized by (111)-Oriented Ge Seeded Vapor-Liquid-Solid Growth.

    PubMed

    Toko, Kaoru; Nakata, Mitsuki; Jevasuwan, Wipakorn; Fukata, Naoki; Suemasu, Takashi

    2015-08-19

    Transfer-free fabrication of vertical Ge nanowires (NWs) on a plastic substrate is demonstrated using a vapor-liquid-solid (VLS) method. The crystal quality of Ge seed layers (50 nm thickness) prepared on plastic substrates strongly influenced the VLS growth morphology, i.e., the density, uniformity, and crystal quality of Ge NWs. The metal-induced layer exchange yielded a (111)-oriented Ge seed layer at 325 °C, which allowed for the VLS growth of vertically aligned Ge NWs. The Ge NW array had almost the same quality as that formed on a bulk Ge(111) substrate. Transmission electron microscopy demonstrated that the Ge NWs were defect-free single crystals. The present investigation paves the way for advanced electronic optical devices integrated on a low-cost flexible substrate. PMID:26230716

  1. Phenomenological theory of phase transitions in epitaxial BaxSr1-xTiO3 thin films on (111)-oriented cubic substrates

    NASA Astrophysics Data System (ADS)

    Shirokov, V. B.; Shakhovoy, R. A.; Razumnaya, A. G.; Yuzyuk, Yu. I.

    2015-07-01

    A phenomenological thermodynamic theory of BaxSr1-xTiO3 (BST-x) thin films epitaxially grown on (111)-oriented cubic substrates is developed using the Landau-Devonshire approach. The group-theoretical analysis of the low-symmetry phases was performed taking into account two order parameters: the polarization related to ionic shifts in polar zone-center F1u mode and the out-of-phase rotation of TiO6 octahedra corresponding to the R25 zone-boundary mode in the parent cubic phase P m 3 ¯ m . The eight-order thermodynamic potential for BST-x solid solutions was developed and analyzed. We constructed the "concentration-misfit strain" phase diagram for BST-x thin films at room temperature and found that polar rhombohedral R3m phase with the polarization normal to the substrate is stable for x > 0.72 and negative misfit strains, while ferroelectric monoclinic C2 and Cm phases with in-plane polarization are stable for much smaller x and positive or slightly negative misfit strains. We constructed the "temperature-misfit strain" phase diagrams for several concentrations (x = 1, 0.8, 0.6, 0.4, and 0.2). Systematic changes of the phase transition lines between the paraelectric and ferroelectric phases are discussed. The phase diagrams are useful for practical applications in thin-film engineering.

  2. Enhanced ferroelectric and dielectric properties of (111)-oriented highly cation-ordered PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} thin films

    SciTech Connect

    Chopra, Anuj; Birajdar, Balaji I.; Kim, Yunseok; Alexe, Marin; Hesse, Dietrich

    2013-12-14

    Cation-ordered (111)-oriented epitaxial PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} (PST) thin films were deposited by pulsed laser deposition on SrRuO{sub 3}-electroded SrTiO{sub 3} (111) substrates at three different temperatures of 525 °C, 550 °C, and 575 °C. All the films were well crystalline and (111)-oriented at all the three growth temperatures; however, the films deposited at the temperatures other than 550 °C exhibited the presence of a pyrochlore phase. X-ray diffraction analysis and transmission electron microscopy measurements revealed that the films were epitaxial and highly cation-ordered. In comparison to (001)-oriented PST films, (111)-oriented films on SrRuO{sub 3}/SrTiO{sub 3} (111) exhibited enhanced ferroelectric and dielectric properties with a broad size distribution of cation-ordered domains (5–100 nm). At a measurement temperature of 100 K, the remnant polarization of PST (111) films is almost √3 times larger than the remnant polarization observed for (001)-oriented PST films, which is attributed to the (111) orientation of the films, as the spontaneous polarization in PST lies close to the [111] direction. The observed dielectric constant and loss at 1 kHz were around 1145 and 0.11, respectively. The dielectric constant is thus almost three times higher than for previously reported (001)-oriented PST thin films, most probably due to the enhancement in cation-ordering.

  3. Young's modulus, Poisson's ratio, and residual stress and strain in (111)-oriented scandium nitride thin films on silicon

    NASA Astrophysics Data System (ADS)

    Moram, M. A.; Barber, Z. H.; Humphreys, C. J.; Joyce, T. B.; Chalker, P. R.

    2006-07-01

    Epitaxial scandium nitride films (225nm thick) were grown on silicon by molecular beam epitaxy, using ammonia as a reactive nitrogen source. The main crystallographic orientation of ScN with respect to Si is (111)ScN‖(111)Si and [1-10]ScN‖[0-11]Si; however, some twinning is also present in the films. The films displayed a columnar morphology with rough surfaces, due to low adatom mobility during growth. The strain-free lattice parameter of ScN films grown under optimized conditions was found to be 4.5047±0.0005Å, as determined using high-resolution x-ray diffraction (HRXRD). In-plane and out-of-plane strains were subsequently evaluated using HRXRD and were used to determine the Poisson ratio of ScN along the ⟨111⟩ direction, which is found to be 0.188±0.005. Wafer curvature measurements were made and combined with the strain information to determine the average Young's modulus of the films, which is found to be 270±25GPa. Residual film stresses ranged from -1to1GPa (depending on film growth temperature and film thickness) due to competition between the tensile stress (induced by the differential thermal contraction between the ScN film and the Si substrate) and intrinsic compressive stresses generated during growth.

  4. Magnetic anisotropy of epitaxially (100)- and (111)-oriented Sr0.8Ho0.2CoO3-δ thin films on SrTiO3 substrates

    NASA Astrophysics Data System (ADS)

    Ahn, Yoonho; Seo, Jeongdae; Son, Jong Yeog

    2016-06-01

    We investigated magnetic properties of epitaxial Sr0.8Ho0.2CoO3-δ thin films grown on single crystal SrTiO3 substrates deposited by pulsed laser deposition method. On the single crystal (100) and (111) SrTiO3 substrates, the (100)- and (111)-oriented Sr0.8Ho0.2CoO3-δ thin films were obtained, respectively. The (100)- and (111)-oriented Sr0.8Ho0.2CoO3-δ thin films exhibited rough surface with grains and smooth surface with a step and terrace structure, respectively. This result suggests they grow in an island and layer-by-layer growth mode, respectively. The (111)-oriented Sr0.8Ho0.2CoO3-δ thin film exhibited ferromagnetic hysteresis with remnant magnetization of 0.15 μB / Co . In contrast, superparamagnetic hysteresis was observed in the (100)-oriented Sr0.8Ho0.2CoO3-δ thin film.

  5. Mapping BFO and DOLCE.

    PubMed

    Temal, Lynda; Rosier, Arnaud; Dameron, Olivier; Burgun, Anita

    2010-01-01

    Upper level ontologies are key technology for integrating heterogeneous information coming from different sources. DOLCE and BFO, are the favorite candidates which propose rigorous foundational principles to model any domain. The objective of the AKENATON project is to improve alert management and to support patient-centered medical decision in telecardiology. This requires to integrate information transmitted by implantable cardiac devices with clinical data extracted from patient health records. To achieve this goal, we have designed an ontology of telecardiology based on DOLCE. In order to integrate ontologies based on BFO such as FMA, we have developed a framework for mapping BFO and DOLCE categories in terms of equivalence and subsumption between categories. PMID:20841847

  6. Interfacial dislocations in (111) oriented (Ba{sub 0.7}Sr{sub 0.3})TiO{sub 3} films on SrTiO{sub 3} single crystal

    SciTech Connect

    Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; Xin, Huolin L.; Su, Dong; Kamo, Takafumi; Funakubo, Hiroshi; Wu, Di

    2015-10-05

    We have investigated the interfacial structure of epitaxial (Ba,Sr)TiO{sub 3} films grown on (111)-oriented SrTiO{sub 3} single-crystal substrates using transmission electron microscopy (TEM) techniques. Compared with the (100) epitaxial perovskite films, we observe dominant dislocation half-loop with Burgers vectors of a〈110〉 comprised of a misfit dislocation along 〈112〉, and threading dislocations along 〈110〉 or 〈100〉. The misfit dislocation with Burgers vector of a〈110〉 can dissociate into two ½a〈110〉 partial dislocations and one stacking fault. We found the dislocation reactions occur not only between misfit dislocations, but also between threading dislocations. Via three-dimensional electron tomography, we retrieved the configurations of the threading dislocation reactions. The reactions between threading dislocations lead to a more efficient strain relaxation than do the misfit dislocations alone in the near-interface region of the (111)-oriented (Ba{sub 0.7}Sr{sub 0.3})TiO{sub 3} films.

  7. Interfacial dislocations in (111) oriented (Ba0.7Sr0.3)TiO3 films on SrTiO3 single crystal

    SciTech Connect

    Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; Kamo, Takafumi; Funakubo, Hiroshi; Wu, Di; Xin, Huolin L.; Su, Dong

    2015-10-08

    In this study, we have investigated the interfacial structure of epitaxial (Ba,Sr)TiO3 films grown on (111)-oriented SrTiO3 single-crystal substrates using transmission electron microscopy (TEM) techniques. Compared with the (100) epitaxial perovskite films, we observe dominant dislocation half-loop with Burgers vectors of a<110> comprised of a misfit dislocation along <112>, and threading dislocations along <110> or <100>. The misfit dislocation with Burgers vector of a <110> can dissociate into two ½ a <110> partial dislocations and one stacking fault. We found the dislocation reactions occur not only between misfit dislocations, but also between threading dislocations. Via three-dimensional electron tomography, we retrieved the configurations of the threading dislocation reactions. The reactions between threading dislocations lead to a more efficient strain relaxation than do the misfit dislocations alone in the near-interface region of the (111)-oriented (Ba0.7Sr0.3)TiO3 films.

  8. Local structure of epitaxial GeTe and Ge2Sb2Te5 films grown on InAs and Si substrates with (100) and (111) orientations: An x-ray absorption near-edge structure study

    NASA Astrophysics Data System (ADS)

    Kolobov, A. V.; Fons, P.; Krbal, M.; Tominaga, J.; Giussani, A.; Perumal, K.; Riechert, H.; Calarco, R.; Uruga, T.

    2015-03-01

    GeTe is an end-point of the GeTe-Sb2Te3 quasibinary alloys often referred to as phase-change memory materials. The polycrystalline nature of the crystalline films used in devices and the concomitant presence of grain boundaries complicate detailed structural studies of the local structure. Recent progress in the epitaxial growth of phase-change materials offers unique possibilities for precise structural investigations. In this work, we report on results of x-ray absorption near-edge structure (XANES) studies of GeTe and Ge2Sb2Te5 epitaxial films grown on Si and InAs substrates with (100) and (111) orientations. The results show a strong dependence of the local structure on the substrate material and especially orientation and are discussed in conjunction with polycrystalline samples and ab-initio XANES simulations.

  9. Enhanced photovoltaic properties in bilayer BiFeO3/Bi-Mn-O thin films.

    PubMed

    Chakrabartty, Joyprokash; Nechache, Riad; Harnagea, Catalin; Li, Shun; Rosei, Federico

    2016-05-27

    We report an external solar power conversion efficiency of ∼1.43% in BiFeO3(BFO)/BiMnO3(BMO) bilayer thin films. Both films are epitaxially grown on (111) oriented niobium doped SrTiO3 (NSTO) single crystal substrates by pulsed laser deposition. By illuminating the BFO/BMO films under 1 Sun (AM 1.5 G), we found a remarkably high fill factor of ∼0.72, much higher than values reported for devices based on BFO or BMO alone. In addition, we demonstrate that the photocurrent density and photovoltage are tunable by changing the polarization direction in the BFO/BMO bilayer, as confirmed by the macroscopic polarization-voltage (P-V) hysteresis loop. This effect is described in terms of a more favorable energy band alignment of the electrode/bilayer/NSTO heterostructure junction, which controls photocarrier separation. PMID:27094952

  10. Enhanced photovoltaic properties in bilayer BiFeO3/Bi-Mn-O thin films

    NASA Astrophysics Data System (ADS)

    Chakrabartty, Joyprokash; Nechache, Riad; Harnagea, Catalin; Li, Shun; Rosei, Federico

    2016-05-01

    We report an external solar power conversion efficiency of ∼1.43% in BiFeO3(BFO)/BiMnO3(BMO) bilayer thin films. Both films are epitaxially grown on (111) oriented niobium doped SrTiO3 (NSTO) single crystal substrates by pulsed laser deposition. By illuminating the BFO/BMO films under 1 Sun (AM 1.5 G), we found a remarkably high fill factor of ∼0.72, much higher than values reported for devices based on BFO or BMO alone. In addition, we demonstrate that the photocurrent density and photovoltage are tunable by changing the polarization direction in the BFO/BMO bilayer, as confirmed by the macroscopic polarization–voltage (P–V) hysteresis loop. This effect is described in terms of a more favorable energy band alignment of the electrode/bilayer/NSTO heterostructure junction, which controls photocarrier separation.

  11. Effects of ferroelectric-poling-induced strain on magnetic and transport properties of La0.67Ba0.33MnO3 thin films grown on (111)-oriented ferroelectric substrates

    NASA Astrophysics Data System (ADS)

    Zhu, Q. X.; Zheng, M.; Yang, M. M.; Li, X. M.; Wang, Y.; Shi, X.; Chan, H. L. W.; Luo, H. S.; Li, X. G.; Zheng, R. K.

    2013-09-01

    La0.67Ba0.33MnO3 thin films were epitaxially grown on (111)-oriented 0.31Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb2/3)O3-0.34PbTiO3 ferroelectric single-crystal substrates. During ferroelectric poling and polarization rotation, the resistance of La0.67Ba0.33MnO3 films tracks the electric-field-induced in-plane strain of substrates effectively, implying strain-mediated coupling. Upon poling along the [111] direction, ferromagnetism is suppressed for T < 175 K, but enhanced for T > 175 K, which is explained by magnetoelastic coupling that modifies the film's magnetic anisotropy. Our findings also show that the magnetic field has an opposite effect on the strain-tunability of resistance [i.e.,(ΔR/R)strain] above and below the Curie temperature TC, which is interpreted within the framework of phase separation.

  12. Growth of (111) oriented NiFe{sub 2}O{sub 4} polycrystalline thin films on Pt (111) via sol-gel processing

    SciTech Connect

    Seifikar, Safoura; Sachet, Edward; Rawdanowicz, Thomas; Schwartz, Justin; Tabei, Ali; Bassiri-Gharb, Nazanin

    2012-09-15

    Polycrystalline NiFe{sub 2}O{sub 4} (NFO) thin films are grown on (111) platinized Si substrates via chemical solution processing. {theta}-2{theta} x-ray diffraction, x-ray pole figures and electron diffraction indicate that the NFO has a high degree of <111> uniaxial texture normal to the film plane. The texturing is initiated by nucleation of (111) planes at the Pt interface and is enhanced with decreasing film thickness. As the NFO magnetic easy-axis is <111>, the out-of-plane magnetization exhibits improved M{sub r}/M{sub s} and coercivity with respect to randomly oriented films on silicon substrates. The out-of-plane M{sub r}/M{sub s} ratio for (111) textured NFO thin film is improved from 30% in 150 nm-thick films to above 70% in 50 nm-thick films. The improved out-of-plane magnetic anisotropy is comparable to epitaxial NFO films of comparable thickness deposited by pulsed laser deposition and sputtering.

  13. Characterization of highly (110)- and (111)-oriented Pb(Zr,Ti)O{sub 3} films on BaPbO{sub 3} electrode using Ru conducting barrier

    SciTech Connect

    Liang, C.-S.; Wu, J.-M.

    2005-07-11

    Highly non-(001)-oriented Pb(Zr,Ti)O{sub 3} (PZT) films have been fabricated by rf-magnetron sputtering. The preferential (110)-oriented BaPbO{sub 3} (BPO) deposited on Ru buffer layer induces the growth of (110)-oriented PZT film. With the aid of self-organized growth of PZT, the orientation of the film deposited on random-oriented BPO/Pt(111)/Ru(002) is (111)-preferred. The insertion of Pt layer between BPO and Ru changes the orientation of PZT from (110) to (111) and prevents the oxygen diffusion. These non-(001)-oriented PZT films possess more superior ferroelectric, fatigue, and retention properties than those of (001)-oriented PZT films.

  14. Characterization of highly (110)- and (111)-oriented Pb(Zr ,Ti)O3 films on BaPbO3 electrode using Ru conducting barrier

    NASA Astrophysics Data System (ADS)

    Liang, Chun-Sheng; Wu, Jenn-Ming

    2005-07-01

    Highly non-(001)-oriented Pb(Zr ,Ti)O3 (PZT) films have been fabricated by rf-magnetron sputtering. The preferential (110)-oriented BaPbO3 (BPO) deposited on Ru buffer layer induces the growth of (110)-oriented PZT film. With the aid of self-organized growth of PZT, the orientation of the film deposited on random-oriented BPO /Pt(111)/Ru(002) is (111)-preferred. The insertion of Pt layer between BPO and Ru changes the orientation of PZT from (110) to (111) and prevents the oxygen diffusion. These non-(001)-oriented PZT films possess more superior ferroelectric, fatigue, and retention properties than those of (001)-oriented PZT films.

  15. Computational Study of the Cation-Modified GSH Peptide Interactions With Perovskite-Type BFO-(111) Membranes Under Aqueous Conditions.

    PubMed

    Bian, Liang; Dong, Fa-Qin; Song, Mian-Xin; Xu, Jin-Bao; Zhang, Xiao-Yan

    2015-12-01

    We elucidated a number of facets regarding glutathione (GSH)-bismuth ferrite (BiFeO3, BFO) interactions and reactivity that have previously remained unexplored on a molecular level. In this approach, the cation-modified reduced GSH (or oxidised glutathione (GS·)) formed on the (111)-oriented BiFeO3 membrane (namely BFO-(111)) can serve as an efficient quencher, and the luminescence mechanism is explained in aqueous conditions. Notably, we suggest the use of Fe(2+)↓ ion as an electron donor and K(+) ion as an electron acceptor to exert a "gluing" effect on the glutamic acid (Glu) and glycine (Gly) side chains, producing an exposed sulfhydryl (-SH) configuration. This method may enable the rational design of a convenient platform for biosensors. PMID:26061445

  16. Computational Study of the Cation-Modified GSH Peptide Interactions With Perovskite-Type BFO-(111) Membranes Under Aqueous Conditions

    NASA Astrophysics Data System (ADS)

    Bian, Liang; Dong, Fa-qin; Song, Mian-xin; Xu, Jin-bao; Zhang, Xiao-yan

    2015-06-01

    We elucidated a number of facets regarding glutathione (GSH)-bismuth ferrite (BiFeO3, BFO) interactions and reactivity that have previously remained unexplored on a molecular level. In this approach, the cation-modified reduced GSH (or oxidised glutathione (GS·)) formed on the (111)-oriented BiFeO3 membrane (namely BFO-(111)) can serve as an efficient quencher, and the luminescence mechanism is explained in aqueous conditions. Notably, we suggest the use of Fe2+↓ ion as an electron donor and K+ ion as an electron acceptor to exert a "gluing" effect on the glutamic acid (Glu) and glycine (Gly) side chains, producing an exposed sulfhydryl (-SH) configuration. This method may enable the rational design of a convenient platform for biosensors.

  17. Simultaneous achievement of high dielectric constant and low temperature dependence of capacitance in (111)-oriented BaTiO3-Bi(Mg0.5Ti0.5)O3-BiFeO3 solid solution thin films

    NASA Astrophysics Data System (ADS)

    Kimura, Junichi; Chentir, Mohamed-Tahar; Shimizu, Takao; Uchida, Hiroshi; Funakubo, Hiroshi

    2016-01-01

    The temperature dependence of the capacitance of (111)c-oriented (0.90-x)BaTiO3-0.10Bi(Mg0.5Ti0.5)O3-xBiFeO3 solid solution films is investigated. These films are prepared on (111)cSrRuO3/(111)Pt/TiO2/SiO2/(100)Si substrates by the chemical solution deposition technique. All the films have perovskite structures and the crystal symmetry at room temperature varies with increasing x ratio, from pseudocubic when x = 0-0.30 to rhombohedral when x = 0.50-0.90. The pseudocubic phase shows a high relative dielectric constant (ɛr) (ranging between 400 and 560 at room temperature and an operating frequency of 100 kHz) and a low temperature dependence of capacitance up to 400°C, while maintaining a dielectric loss (tan δ) value of less than 0.2 at 100 kHz. In contrast, ɛr for the rhombohedral phase increases monotonically with increasing temperature up to 250°C, and increasingly high tan δ values are recorded at higher temperatures. These results indicate that pseudocubic (0.90-x)BaTiO3-0.10Bi(Mg0.5Ti0.5)O3-xBiFeO3 solid solution films with (111) orientation are suitable candidates for high-temperature capacitor applications.

  18. Induced Superconductivity and Engineered Josephson Tunneling Devices in Epitaxial (111)-Oriented Gold/Vanadium Heterostructures

    NASA Astrophysics Data System (ADS)

    Wei, Peng; Katmis, Ferhat; Chang, Cui-Zu; Moodera, Jagadeesh S.

    2016-04-01

    We report a unique experimental approach to create topological superconductors by inducing superconductivity into epitaxial metallic thin film with strong spin-orbit coupling. Utilizing molecular beam epitaxy technique under ultra-high vacuum condition, we are able to achieve (111) oriented single phase of gold (Au) thin film grown on a well-oriented vanadium (V) s-wave superconductor film with clean interface. We obtained atomically smooth Au thin films with thicknesses even down to below a nanometer showing near-ideal surface quality. The as-grown V/Au bilayer heterostructure exhibits superconducting transition at around 4 K. Clear Josephson tunneling and Andreev reflection are observed in S-I-S tunnel junctions fabricated from the epitaxial bi-layers. The barrier thickness dependent tunneling and the associated subharmonic gap structures (SGS) confirmed the induced superconductivity in Au (111), paving the way for engineering thin film heterostructure based p-wave superconductors and nano devices for Majorana fermion.

  19. Au induced low-temperature formation of preferentially (111)-oriented crystalline Ge on insulator

    NASA Astrophysics Data System (ADS)

    Okamoto, Hayato; Kudo, Kohei; Nomitsu, Tatsushi; Mochii, Ryosuke; Moto, Kenta; Takakura, Kenichiro; Tsunoda, Isao

    2016-04-01

    The effects of Au insertion in solid-phase crystallization for amorphous Ge films on SiO2/Si substrates were investigated to achieve oriented crystalline Ge. After high-temperature annealing above 300 °C, Au atoms were highly diffused in the amorphous Ge layer. The resulting crystalline Ge consisted of random grains formed by crystal nucleation in the entire Ge region. However, when annealing temperature was decreased to below 250 °C, Au atoms were localized at their initial position even after a long annealing (20 h). Moreover, formation of preferentially (111)-oriented crystalline Ge was achieved without using the metal-induced layer-exchange crystallization method. These results suggest that crystal nucleation preferentially occurs at the amorphous Ge/Au interface, and subsequently the nucleus growth progresses into the Ge layer.

  20. Photonic nano-structures on (111)-oriented diamond

    SciTech Connect

    Neu, Elke; Appel, Patrick; Ganzhorn, Marc; Miguel-Sánchez, Javier; Maletinsky, Patrick; Lesik, Margarita; Jacques, Vincent; Mille, Vianney; Tallaire, Alexandre; Achard, Jocelyn

    2014-04-14

    We demonstrate the fabrication of single-crystalline diamond nanopillars on a (111)-oriented chemical vapor deposited diamond substrate. This crystal orientation offers optimal coupling of nitrogen-vacancy (NV) center emission to the nanopillar mode and is thus advantageous over previous approaches. We characterize single native NV centers in these nanopillars and find one of the highest reported saturated fluorescence count rates in single crystalline diamond in excess of 10{sup 6} counts per second. We show that our nano-fabrication procedure conserves the preferential alignment as well as the spin coherence of the NVs in our structures. Our results will enable a new generation of highly sensitive probes for NV magnetometry and pave the way toward photonic crystals with optimal orientation of the NV center's emission dipole.

  1. Induced Superconductivity and Engineered Josephson Tunneling Devices in Epitaxial (111)-Oriented Gold/Vanadium Heterostructures.

    PubMed

    Wei, Peng; Katmis, Ferhat; Chang, Cui-Zu; Moodera, Jagadeesh S

    2016-04-13

    We report a unique experimental approach to create topological superconductors by inducing superconductivity into epitaxial metallic thin film with strong spin-orbit coupling. Utilizing molecular beam epitaxy technique under ultrahigh vacuum conditions, we are able to achieve (111) oriented single phase of gold (Au) thin film grown on a well-oriented vanadium (V) s-wave superconductor film with clean interface. We obtained atomically smooth Au thin films with thicknesses even down to below a nanometer showing near-ideal surface quality. The as-grown V/Au bilayer heterostructure exhibits superconducting transition at around 3.9 K. Clear Josephson tunneling and Andreev reflection are observed in S-I-S tunnel junctions fabricated from the epitaxial bilayers. The barrier thickness dependent tunneling and the associated subharmonic gap structures (SGS) confirmed the induced superconductivity in Au (111), paving the way for engineering thin film heterostructures based on p-wave superconductivity and nano devices exploiting Majorana Fermions for quantum computing. PMID:26943807

  2. Polymethyl methacrylate (PMMA)-bismuth ferrite (BFO) nanocomposite: low loss and high dielectric constant materials with perceptible magnetic properties.

    PubMed

    Tamboli, Mohaseen S; Palei, Prakash K; Patil, Santosh S; Kulkarni, Milind V; Maldar, Noormahmad N; Kale, Bharat B

    2014-09-21

    Herein, poly(methyl methacrylate)-bismuth ferrite (PMMA-BFO) nanocomposites were successfully prepared by an in situ polymerization method for the first time. Initially, the as prepared bismuth ferrite (BFO) nanoparticles were dispersed in the monomer, (methyl methacrylate) by sonication. Benzoyl peroxide was used to initiate the polymerization reaction in ethyl acetate medium. The nanocomposite films were subjected to X-ray diffraction analysis (XRD), (1)H NMR, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), infrared spectroscopy (IR), dielectric and magnetic characterizations. The dielectric measurement of the nanocomposites was investigated at a frequency range of 10 Hz to 1 MHz. It was found that the nanocomposites not only showed a significantly increased value of the dielectric constant with an increase in the loading percentage of BFO as compared to pure PMMA, but also exhibited low dielectric loss values over a wide range of frequencies. The values of the dielectric constant and dielectric loss of the PMMA-BFO5 (5% BFO loading) sample at 1 kHz frequency was found be ~14 and 0.037. The variation of the ferromagnetic response of the nanocomposite was consistent with the varying volume percentage of the nanoparticles. The remnant magnetization (Mr) and saturation magnetization (Ms) values of the composites were found to be enhanced by increasing the loading percentage of BFO. The value of Ms for PMMA-BFO5 was found to be ~6 emu g(-1). The prima facie observations suggest that the nanocomposite is a potential candidate for application in high dielectric constant capacitors. Significantly, based on its magnetic properties the composite will also be useful for use in hard disk components. PMID:25050918

  3. Second harmonic generation in photonic crystal cavities in (111)-oriented GaAs

    SciTech Connect

    Buckley, Sonia Radulaski, Marina; Vučković, Jelena; Biermann, Klaus

    2013-11-18

    We demonstrate second harmonic generation at telecommunications wavelengths in photonic crystal cavities in (111)-oriented GaAs. We fabricate 30 photonic crystal structures in both (111)- and (100)-oriented GaAs and observe an increase in generated second harmonic power in the (111) orientation, with the mean power increased by a factor of 3, although there is a large scatter in the measured values. We discuss possible reasons for this increase, in particular, the reduced two photon absorption for transverse electric modes in (111) orientation, as well as a potential increase due to improved mode overlap.

  4. Structural and magnetic properties of (111) oriented annealed ultrathin Co/Pt multilayers

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Tripathi, S.; Tripathi, J.

    2016-05-01

    The effect of annealing on the structural and magnetic properties of Co/Pt multilayers was studied as a function of annealing temperature. The ultrathin layers of Pt and Co were deposited to make [Pt 1nm/Co 1nm]x20 multilayer on Si (100) substrate using MBE technique. The structural, magnetic and electronic properties were recorded using XRD, SQUID and XPS techniques, respectively. M-H loop of as deposited sample shows soft magnetic nature with coercivity value of 350 Oe which increases to 974 Oe in 500°C annealed film. When studied at low temperature (5K), the coercivity of 592 Oe is obtained in the as deposited sample which increases to 1626 Oe after annealing. In addition, as revealed by X-ray photoelectron spectroscopy, modifications in core level and valance band are observed. The observed changes in magnetic and electronic properties are attributed to structural modifications in correlation with the changes in (111) orientation of the films seen by X-ray diffraction.

  5. Oxygen concentration and its effect on the leakage current in BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Yang, H.; Wang, Y. Q.; Wang, H.; Jia, Q. X.

    2010-01-01

    Epitaxial c-axis oriented BiFeO3 (BFO) films were fabricated on (001) oriented SrTiO3 substrates by pulsed laser deposition. Nuclear resonance backscattering spectrometry was used to directly measure the oxygen concentration of as-deposited and annealed BFO films. Compared to the ideal stoichiometry of BFO, the as-deposited BFO film shows more than 10% oxygen deficiency. However, postannealing the as-deposited BFO films reduces the oxygen deficiency almost half. The reduced oxygen vacancies in annealed BFO films are believed to be responsible for the different leakage mechanisms and the two orders of magnitude drop in leakage current density.

  6. Highly effective strain-induced band-engineering of (111) oriented, direct-gap GeSn crystallized on amorphous SiO2 layers

    NASA Astrophysics Data System (ADS)

    Li, Haofeng; Wang, Xiaoxin; Liu, Jifeng

    2016-03-01

    We demonstrate highly effective strain-induced band-engineering of (111) oriented direct-gap Ge1-xSnx thin films (0.074 < x < 0.085) crystallized on amorphous SiO2 towards 3D photonic integration. Due to a much smaller Poisson's ratio for (111) vs. (100) orientation, 0.44% thermally induced biaxial tensile strain reduces the direct-gap by 0.125 eV towards enhanced direct-gap semiconductor properties, twice as effective as the tensile strain in Ge(100) films. Correspondingly, the optical response is extended to λ = 2.8 μm. A dilatational deformation potential of a = -12.8 ± 0.8 eV is derived. These GeSn films also demonstrate high thermal stability, offering both excellent direct-gap optoelectronic properties and fabrication/operation robustness for integrated photonics.

  7. Thickness dependence of exchange coupling in (111)-oriented perovskite oxide superlattices

    NASA Astrophysics Data System (ADS)

    Jia, Yue; Chopdekar, Rajesh V.; Arenholz, Elke; Liu, Zhiqi; Biegalski, Michael D.; Porter, Zachary D.; Mehta, Apurva; Takamura, Yayoi

    2016-03-01

    Epitaxial L a0.7S r0.3Mn O3(LSMO )/L a0.7S r0.3Fe O3 (LSFO) superlattices on (111)-oriented SrTi O3 substrates with sublayer thicknesses ranging from 3 to 60 unit cells (u.c.) were synthesized and characterized. Detailed analysis of their structural, electronic, and magnetic properties were performed to explore the effect of sublayer thickness on the magnetic structure and exchange coupling at (111)-oriented perovskite oxide interfaces. In the ultrathin limit (3-6 u.c.), we find that the antiferromagnetic (AF) properties of the LSFO sublayers are preserved with an out-of-plane canting of the AF spin axis, while the ferromagnetic (FM) properties of the LSMO sublayers are significantly depressed. For thicker LSFO layers (>9 u.c.), the out-of-plane canting of the AF spin axis is only present in superlattices with thick LSMO sublayers. As a result, exchange coupling in the form of spin-flop coupling exists only in superlattices which display both robust ferromagnetism and out-of-plane canting of the AF spin axis.

  8. First principles simulation of temperature dependent electronic transition of FM-AFM phase BFO.

    PubMed

    Bian, Liang; Xu, Jin-bao; Song, Mian-xin; Dong, Fa-qin; Dong, Hai-liang; Shi, Fa-Nian; Zhang, Xiao-Yan; Duan, Tao

    2015-04-01

    Understanding how temperature affects the electronic transitions of BFO is important for design of BiFeO3 (BFO)-based temperature-sensitive device. Hitherto, however, there have been only very limited reports of the quantitative simulation. Here, we used density functional theory (DFT) and two-dimensional correlation analysis (2D-CA) techniques to calculate the systematic variations in electronic transitions of BFO crystal, over a range of temperature (50~1500 K). The results suggest that the heat accumulation accelerates the O-2p(4) orbital splitting, inducing the Fe(3+)-3d(5) → Fe(2+)-3d(5)d(0) charge disproportionation. The origin is observed as the temperature-dependent electron transfer process changes from threefold degeneracy to twofold degeneracy. Additionally, the crystallographic orientation (111) can be used to control the 2p-hole-induced electronic transition as O → unoccupied Fe(3+)-3d(5), in comparison to the O → Bi-6p(3) + Fe(3+)-3d(5)d(0) on the orientations (001) and (101). This study offers new perspective on the improvement of BFO-based temperature-sensitive device. PMID:25786830

  9. Surface and grain boundary interdiffusion in nanometer-scale LSMO/BFO bilayer

    NASA Astrophysics Data System (ADS)

    Kumar, Virendra; Gaur, Anurag; Choudhary, R. J.; Gupta, Mukul

    2016-05-01

    Epitaxial 150 nm thick LSMO/BFO bilayer is deposited on STO (100) substrate by pulsed laser deposition, to study magnetoelectric effect. Unexpected low value of room temperature magnetization in bilayer indicates towards the possibility of interdiffusion. Further, sharp fall in the value of TC (53 K) also added our anxiety towards possible interdiffusion in BFO/LSMO system. Low-angle x-ray diffraction technique is used to investigate interdiffusion phenomena, and the temperature-dependent interdiffusivity is obtained by accurately monitoring the decay of the first-order modulation peak as a function of annealing time. It has been found that the diffusivity at different temperatures follows Arrhenius-type behavior. X-ray reflection (XRR) pattern obtained for the bilayer could not be fitted in the Parratt's formalism, which confirms the interdiffusion in it. Depth profiles of 209Bi, 56Fe ions measured by secondary ion mass spectroscope (SIMS) further substantiate the diffusion of these ions from upper BFO layer into lower LSMO layer.

  10. Fabrication of (111)-oriented Ca0.5Sr0.5IrO3/SrTiO3 superlattices—A designed playground for honeycomb physics

    NASA Astrophysics Data System (ADS)

    Hirai, Daigorou; Matsuno, Jobu; Takagi, Hidenori

    2015-04-01

    We report the fabrication of (111)-oriented superlattice structures with alternating 2m-layers (m = 1, 2, and 3) of Ca0.5Sr0.5IrO3 perovskite and two layers of SrTiO3 perovskite on SrTiO3(111) substrates. In the case of m = 1 bilayer films, the Ir sub-lattice is a buckled honeycomb, where a topological state may be anticipated. The successful growth of superlattice structures on an atomic level along the [111] direction was clearly demonstrated by superlattice reflections in x-ray diffraction patterns and by atomically resolved transmission electron microscope images. The ground states of the superlattice films were found to be magnetic insulators, which may suggest the importance of electron correlations in Ir perovskites in addition to the much discussed topological effects.

  11. Fabrication of (111)-oriented Ca{sub 0.5}Sr{sub 0.5}IrO{sub 3}/SrTiO{sub 3} superlattices—A designed playground for honeycomb physics

    SciTech Connect

    Hirai, Daigorou; Matsuno, Jobu; Takagi, Hidenori

    2015-04-01

    We report the fabrication of (111)-oriented superlattice structures with alternating 2m-layers (m = 1, 2, and 3) of Ca{sub 0.5}Sr{sub 0.5}IrO{sub 3} perovskite and two layers of SrTiO{sub 3} perovskite on SrTiO{sub 3}(111) substrates. In the case of m = 1 bilayer films, the Ir sub-lattice is a buckled honeycomb, where a topological state may be anticipated. The successful growth of superlattice structures on an atomic level along the [111] direction was clearly demonstrated by superlattice reflections in x-ray diffraction patterns and by atomically resolved transmission electron microscope images. The ground states of the superlattice films were found to be magnetic insulators, which may suggest the importance of electron correlations in Ir perovskites in addition to the much discussed topological effects.

  12. Computational study of the RGD-peptide interactions with perovskite-type BFO-(1 1 1) membranes under aqueous conditions

    NASA Astrophysics Data System (ADS)

    Li, Hai-long; Bian, Liang; Hou, Wen-ping; Dong, Fa-Qin; Song, Mian-Xin; Zhang, Xiao-yan; Wang, Li-sheng

    2016-07-01

    We elucidated a number of facets regarding arginine-glycine-aspartate (RGD)-bismuth ferrite (BFO)-(1 1 1) membrane interactions and reactivity that have previously remained unexplored on a molecular level. Results demonstrate the intra-molecular interaction facilitates a "horseshoe" structure of RGD adsorbed onto the BFO-(1 1 1) membrane, through the electrostatic (Asp-cation-Fe) and water-bridge (Osbnd H2O and H2Osbnd NH2) interactions. The effect of structural and electron-transfer interactions is attributed to the cation-valences, indicating that the divalent cations are electron-acceptors and the monovalent cations as electron-donors. Notably, the strongly bound Ca2+ ion exerts a "gluing" effect on the Asp-side-chain, indicating a tightly packed RGD-BFO configuration. Thus, modulating the biological response of BFO-(1 1 1) membrane will allow us to design more appropriate interfaces for implantable diagnostic and therapeutic perovskite-type micro-devices.

  13. Optical properties of epitaxial BiFeO3 thin film grown on SrRuO3-buffered SrTiO3 substrate

    PubMed Central

    2014-01-01

    The BiFeO3 (BFO) thin film was deposited by pulsed-laser deposition on SrRuO3 (SRO)-buffered (111) SrTiO3 (STO) substrate. X-ray diffraction pattern reveals a well-grown epitaxial BFO thin film. Atomic force microscopy study indicates that the BFO film is rather dense with a smooth surface. The ellipsometric spectra of the STO substrate, the SRO buffer layer, and the BFO thin film were measured, respectively, in the photon energy range 1.55 to 5.40 eV. Following the dielectric functions of STO and SRO, the ones of BFO described by the Lorentz model are received by fitting the spectra data to a five-medium optical model consisting of a semi-infinite STO substrate/SRO layer/BFO film/surface roughness/air ambient structure. The thickness and the optical constants of the BFO film are obtained. Then a direct bandgap is calculated at 2.68 eV, which is believed to be influenced by near-bandgap transitions. Compared to BFO films on other substrates, the dependence of the bandgap for the BFO thin film on in-plane compressive strain from epitaxial structure is received. Moreover, the bandgap and the transition revealed by the Lorentz model also provide a ground for the assessment of the bandgap for BFO single crystals. PMID:24791162

  14. Optical properties of epitaxial BiFeO3 thin film grown on SrRuO3-buffered SrTiO3 substrate.

    PubMed

    Xu, Ji-Ping; Zhang, Rong-Jun; Chen, Zhi-Hui; Wang, Zi-Yi; Zhang, Fan; Yu, Xiang; Jiang, An-Quan; Zheng, Yu-Xiang; Wang, Song-You; Chen, Liang-Yao

    2014-01-01

    The BiFeO3 (BFO) thin film was deposited by pulsed-laser deposition on SrRuO3 (SRO)-buffered (111) SrTiO3 (STO) substrate. X-ray diffraction pattern reveals a well-grown epitaxial BFO thin film. Atomic force microscopy study indicates that the BFO film is rather dense with a smooth surface. The ellipsometric spectra of the STO substrate, the SRO buffer layer, and the BFO thin film were measured, respectively, in the photon energy range 1.55 to 5.40 eV. Following the dielectric functions of STO and SRO, the ones of BFO described by the Lorentz model are received by fitting the spectra data to a five-medium optical model consisting of a semi-infinite STO substrate/SRO layer/BFO film/surface roughness/air ambient structure. The thickness and the optical constants of the BFO film are obtained. Then a direct bandgap is calculated at 2.68 eV, which is believed to be influenced by near-bandgap transitions. Compared to BFO films on other substrates, the dependence of the bandgap for the BFO thin film on in-plane compressive strain from epitaxial structure is received. Moreover, the bandgap and the transition revealed by the Lorentz model also provide a ground for the assessment of the bandgap for BFO single crystals. PMID:24791162

  15. Atomistic Simulation of Electronic and Optical Properties of (100), (110) and (111) Oriented InAs/GaAs Quantum Dots

    NASA Astrophysics Data System (ADS)

    Chimalgi, Vinay; Ahmed, Shaikh

    2014-03-01

    Recent advances in growth techniques and increasing number of experimental studies have made semiconducting InAs/GaAs quantum dots (QDs) grown along different crystallographic directions a reality and promising systems for applications in infrared detection, optical memories, laser, and in quantum cryptography as single photon sources and quantum computation. However, only few theoretical investigations have been performed on these QDs due to the complex nature of the coupling of atomicity, structural fields, polarization, and quantum size-quantization, all strong function of the crystallographic direction. The objective of this paper is to integrate a computational framework employing a combination of fully atomistic valence force-field molecular mechanics and 20-band sp3 s *d5 -SO tight-binding based electronic bandstructure models, and numerically investigate the effects of internal fields on the electronic and optical properties of InAs/GaAs quantum dots grown on (100), (110), and (111) orientated substrates. It is found that, while piezoelectricity has largest effects on lowering the symmetry of (100) oriented QDs, its effect is minimum in (111) orientated QDs. Supported by the U.S. National Science Foundation Grant No. 1102192.

  16. Enhancement of photoinduced electrical properties of Al-doped ZnO/BiFeO3 layered thin films prepared by chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Katayama, Takeshi; Sakamoto, Wataru; Yuitoo, Isamu; Takeuchi, Teruaki; Hayashi, Koichiro; Yogo, Toshinobu

    2015-10-01

    Polycrystalline BiFeO3 and Al-doped ZnO/BiFeO3 bilayered thin films were prepared on Pt/TiOx/SiO2/Si substrates by chemical solution deposition. Their photoinduced electrical properties under blue light irradiation were characterized. The rapid on/off response of the photocurrent to light in unpoled BiFeO3 (BFO) and Al-doped ZnO/BiFeO3 (AZO/BFO) thin films was demonstrated. The AZO/BFO layered film exhibited an approximately triple-digit larger photocurrent in comparison with a BFO single-layer film. This is attributable to the photoexcited carrier generation effect at the interface between AZO (n-type) and BFO (p-type) films. Furthermore, in the AZO/BFO layered structure, the direction of the internal bias electric field caused by the space charge distribution in the unpoled BFO film is the same as that of the built-in electric field by forming a p-n junction of AZO and BFO layers. Photovoltaic properties were also improved by fabricating such a layered film. On the other hand, when the placement of BFO to AZO was reversed, the photoelectric current decreased to approximately one-tenth of that of the BFO single-layer film. In the BFO/AZO film, the internal electric field at the p-n junction between BFO and AZO is considered to have an orientation opposite to the self-bias field formed in the BFO film.

  17. Electronic structures of [001]- and [111]-oriented InSb and GaSb free-standing nanowires

    SciTech Connect

    Liao, Gaohua; Luo, Ning; Yang, Zhihu; Chen, Keqiu; Xu, H. Q. E-mail: hongqi.xu@ftf.lth.se

    2015-09-07

    We report on a theoretical study of the electronic structures of InSb and GaSb nanowires oriented along the [001] and [111] crystallographic directions. The nanowires are described by atomistic, tight-binding models, including spin-orbit interaction. The band structures and the wave functions of the nanowires are calculated by means of a Lanczos iteration algorithm. For the [001]-oriented InSb and GaSb nanowires, the systems with both square and rectangular cross sections are considered. Here, it is found that all the energy bands are doubly degenerate. Although the lowest conduction bands in these nanowires show good parabolic dispersions, the top valence bands show rich and complex structures. In particular, the topmost valence bands of the nanowires with a square cross section show a double maximum structure. In the nanowires with a rectangular cross section, this double maximum structure is suppressed, and the top valence bands gradually develop into parabolic bands as the aspect ratio of the cross section is increased. For the [111]-oriented InSb and GaSb nanowires, the systems with hexagonal cross sections are considered. It is found that all the bands at the Γ-point are again doubly degenerate. However, some of them will split into non-degenerate bands when the wave vector moves away from the Γ-point. Although the lowest conduction bands again show good parabolic dispersions, the topmost valence bands do not show the double maximum structure. Instead, they show a single maximum structure with its maximum at a wave vector slightly away from the Γ-point. The wave functions of the band states near the band gaps of the [001]- and [111]-oriented InSb and GaSb nanowires are also calculated and are presented in terms of probability distributions in the cross sections. It is found that although the probability distributions of the band states in the [001]-oriented nanowires with a rectangular cross section could be qualitatively described by one-band effective

  18. Electronic structures of [001]- and [111]-oriented InSb and GaSb free-standing nanowires

    NASA Astrophysics Data System (ADS)

    Liao, Gaohua; Luo, Ning; Yang, Zhihu; Chen, Keqiu; Xu, H. Q.

    2015-09-01

    We report on a theoretical study of the electronic structures of InSb and GaSb nanowires oriented along the [001] and [111] crystallographic directions. The nanowires are described by atomistic, tight-binding models, including spin-orbit interaction. The band structures and the wave functions of the nanowires are calculated by means of a Lanczos iteration algorithm. For the [001]-oriented InSb and GaSb nanowires, the systems with both square and rectangular cross sections are considered. Here, it is found that all the energy bands are doubly degenerate. Although the lowest conduction bands in these nanowires show good parabolic dispersions, the top valence bands show rich and complex structures. In particular, the topmost valence bands of the nanowires with a square cross section show a double maximum structure. In the nanowires with a rectangular cross section, this double maximum structure is suppressed, and the top valence bands gradually develop into parabolic bands as the aspect ratio of the cross section is increased. For the [111]-oriented InSb and GaSb nanowires, the systems with hexagonal cross sections are considered. It is found that all the bands at the Γ-point are again doubly degenerate. However, some of them will split into non-degenerate bands when the wave vector moves away from the Γ-point. Although the lowest conduction bands again show good parabolic dispersions, the topmost valence bands do not show the double maximum structure. Instead, they show a single maximum structure with its maximum at a wave vector slightly away from the Γ-point. The wave functions of the band states near the band gaps of the [001]- and [111]-oriented InSb and GaSb nanowires are also calculated and are presented in terms of probability distributions in the cross sections. It is found that although the probability distributions of the band states in the [001]-oriented nanowires with a rectangular cross section could be qualitatively described by one-band effective

  19. Ultrafast photostriction in BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Chen, L. Y.; Luo, C. W.; Chu, Y. H.; Kobayashi, T.

    2012-02-01

    The ultrafast dynamics of BiFeO3 (BFO) thin films was studied by dual-color transient reflectivity measurements (δR/R) from 80 K to room temperature. Based on the thickness-dependent propagating time of the photoinduced strain pulse, the sound velocity along [110] direction of BFO is 4.76 km/s. Anisotropic photostriction effect in BFO generated within short time scale of 5 ps is enhanced by the optical rectification effect. Furthermore, the anomalous changes of the temperaure-dependent δR/R at 130 K and 210 K may reveal the spin-orbital coupling and magnetoelastic effect in BFO.

  20. 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting

    NASA Astrophysics Data System (ADS)

    Mateo, Diego; Esteve-Adell, Iván; Albero, Josep; Royo, Juan F. Sánchez; Primo, Ana; Garcia, Hermenegildo

    2016-06-01

    Development of renewable fuels from solar light appears as one of the main current challenges in energy science. A plethora of photocatalysts have been investigated to obtain hydrogen and oxygen from water and solar light in the last decades. However, the photon-to-hydrogen molecule conversion is still far from allowing real implementation of solar fuels. Here we show that 111 facet-oriented gold nanoplatelets on multilayer graphene films deposited on quartz is a highly active photocatalyst for simulated sunlight overall water splitting into hydrogen and oxygen in the absence of sacrificial electron donors, achieving hydrogen production rate of 1.2 molH2 per gcomposite per h. This photocatalytic activity arises from the gold preferential orientation and the strong gold-graphene interaction occurring in the composite system.

  1. 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting

    PubMed Central

    Mateo, Diego; Esteve-Adell, Iván; Albero, Josep; Royo, Juan F. Sánchez; Primo, Ana; Garcia, Hermenegildo

    2016-01-01

    Development of renewable fuels from solar light appears as one of the main current challenges in energy science. A plethora of photocatalysts have been investigated to obtain hydrogen and oxygen from water and solar light in the last decades. However, the photon-to-hydrogen molecule conversion is still far from allowing real implementation of solar fuels. Here we show that 111 facet-oriented gold nanoplatelets on multilayer graphene films deposited on quartz is a highly active photocatalyst for simulated sunlight overall water splitting into hydrogen and oxygen in the absence of sacrificial electron donors, achieving hydrogen production rate of 1.2 molH2 per gcomposite per h. This photocatalytic activity arises from the gold preferential orientation and the strong gold–graphene interaction occurring in the composite system. PMID:27264495

  2. 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting.

    PubMed

    Mateo, Diego; Esteve-Adell, Iván; Albero, Josep; Royo, Juan F Sánchez; Primo, Ana; Garcia, Hermenegildo

    2016-01-01

    Development of renewable fuels from solar light appears as one of the main current challenges in energy science. A plethora of photocatalysts have been investigated to obtain hydrogen and oxygen from water and solar light in the last decades. However, the photon-to-hydrogen molecule conversion is still far from allowing real implementation of solar fuels. Here we show that 111 facet-oriented gold nanoplatelets on multilayer graphene films deposited on quartz is a highly active photocatalyst for simulated sunlight overall water splitting into hydrogen and oxygen in the absence of sacrificial electron donors, achieving hydrogen production rate of 1.2 molH2 per gcomposite per h. This photocatalytic activity arises from the gold preferential orientation and the strong gold-graphene interaction occurring in the composite system. PMID:27264495

  3. Multiferroics properties in BiFeO3/CoFe2O4 heterostructures thin films deposited on (111) SrTiO3

    NASA Astrophysics Data System (ADS)

    Singh, Gulab; Singh, Manoj K.; Kumar, Aditya; Dussan, S.; Katiyar, Ram S.

    2016-05-01

    The multiferroic properties of BiFeO3-CoFe2O4 (BFO-CFO) heterostructures thin film grown on (111) SrTiO3 (STO) substrates by employing pulsed laser deposition (PLD) method, have been studied.X ray diffraction analysis reveals the presence of BFO and CFO in two separate phases. The heterostructures BFO/CFO/STO(111) thin films show well - shaped hysteresis loop with saturated magnetization and coercive field, which are much larger than pure BFO/STO thin film. The frequency dependent dielectric anomalies in BFO-CFO multilayer are attributed to the interfacial effect across the presence of CFO as a separate phase embedded in BFO matrix.

  4. Microstructure evolution and FEM analysis of a [111] oriented single crystal nickel-based superalloy during tensile creep

    NASA Astrophysics Data System (ADS)

    Tian, Sugui; Li, Qiuyang; Su, Yong; Yu, Huichen; Xie, Jun; Zhang, Shu

    2015-03-01

    By means of the elastic-plastic stress-strain finite element method (FEM), the distribution of the von Mises stress and strain energy density in the regions near the interfaces of the cuboidal γ/ γ' phases is calculated to investigate the rafted behaviors of γ' phase in a [111] oriented single crystal (SC) nickel-based superalloy. Results show that, after fully heat treated, the microstructure of the superalloy consists of the cuboidal γ' phase embedded coherently in the γ matrix and arranged regularly along the <100> orientation. And the parameters and misfits of γ'/ γ phases in the alloy increase with the temperature. After crept for 50 h, the γ' phase in alloy has transformed into the mesh-like rafted structure on (010) plane along [001] and [100] orientations. When the tensile stress is applied along [111] direction, the change of the strain energy on the planes of the cuboidal γ' phase results in the directional diffusion of the elements. Thereinto, compared with (010) plane, the bigger expanding strain occurs on (100) and (001) planes along the [010], [001] and [010], [100] directions, which may trap the Al and Ti atoms with bigger radius to promote the directional growth of γ' phase on (010) plane along [100] and [001] directions. This is thought to be the main reason for the γ' phase directionally growing into the mesh-like rafted structure on (010) plane.

  5. Texture control of multiferroic BiFeO3 polycrystalline films on glass substrates with various metal electrode underlayers

    NASA Astrophysics Data System (ADS)

    Chang, H. W.; Yuan, F. T.; Chen, P. H.; Yu, Y. C.; Lin, P. C.; Wang, C. R.; Jen, S. U.

    2015-05-01

    Texture control of multiferroic BiFeO3 (BFO) polycrystalline films on glass substrates with various metal electrode underlayers at reduced processing temperature of 450 °C has been demonstrated. The structural results confirm the synthesis of perovskite BFO with (001) texture on the refined Pt(111) and L10-FePt(001) electrode layers and with (110) texture on CoPt(111) one. All studied BFO films exhibit typical ferroelectric properties. Larger remanent electrical polarization 2Pr of 135 μC/cm2 and coercive electric field Ec of 495 kV/cm are obtained for BFO(110) film on CoPt(111) electrode as compared to BFO(001) films on Pt(111) and L10-FePt(001) electrodes (2Pr = 93-98 μC/cm2 and Ec of 304-354 kV/cm), which is consistent with the epitaxial BFO films and theoretical calculations. Besides, the ferroelectric properties of the studied BFO films are comparable to BFO films grown on single crystal substrates. The ferroelectric properties with various metal electrode underlayers are related to the orientation of texture and leakage behavior.

  6. Magnetism and electronic structure of (001)- and (111)-oriented LaTiO3 bilayers sandwiched in LaScO3 barriers

    NASA Astrophysics Data System (ADS)

    Weng, Yakui; Dong, Shuai

    2015-05-01

    In this study, the magnetism and electronic structure of LaTiO3 bilayers along both the (001) and (111) orientations are calculated using the density functional theory. The band insulator LaScO3 is chosen as the barrier layer and substrate to obtain the isolating LaTiO3 bilayer. For both the (001)- and (111)-oriented cases, LaTiO3 demonstrates the G-type antiferromagnetism as the ground state, similar to the bulk material. However, the electronic structure is significantly changed. The occupied bands of Ti are much narrower in the (111) case, giving a nearly flat band. As a result, the exchange coupling between nearest-neighbor Ti ions is reformed in these superlattices, which will affect the Néel temperature significantly.

  7. Magnetism and electronic structure of (001)- and (111)-oriented LaTiO{sub 3} bilayers sandwiched in LaScO{sub 3} barriers

    SciTech Connect

    Weng, Yakui; Dong, Shuai

    2015-05-07

    In this study, the magnetism and electronic structure of LaTiO{sub 3} bilayers along both the (001) and (111) orientations are calculated using the density functional theory. The band insulator LaScO{sub 3} is chosen as the barrier layer and substrate to obtain the isolating LaTiO{sub 3} bilayer. For both the (001)- and (111)-oriented cases, LaTiO{sub 3} demonstrates the G-type antiferromagnetism as the ground state, similar to the bulk material. However, the electronic structure is significantly changed. The occupied bands of Ti are much narrower in the (111) case, giving a nearly flat band. As a result, the exchange coupling between nearest-neighbor Ti ions is reformed in these superlattices, which will affect the Néel temperature significantly.

  8. Epitaxial growth of (111)-oriented LaAlO{sub 3}/LaNiO{sub 3} ultra-thin superlattices

    SciTech Connect

    Middey, S.; Meyers, D.; Kareev, M.; Moon, E. J.; Gray, B. A.; Liu, X.; Freeland, J. W.; Chakhalian, J.

    2012-12-24

    The epitaxial stabilization of a single layer or superlattice structures composed of complex oxide materials on polar (111) surfaces is severely burdened by the reconstructions at the interface that commonly arise to neutralize the polarity. We report on the synthesis of high quality LaNiO{sub 3}/mLaAlO{sub 3} pseudo cubic (111) superlattices on polar (111)-oriented LaAlO{sub 3}, the proposed complex oxide candidate for a topological insulating behavior. Comprehensive X-Ray diffraction measurements, reflection high energy electron diffraction, and element specific resonant X-ray absorption spectroscopy affirm their high structural and chemical quality. The study offers an opportunity to fabricate interesting interface and topology controlled (111)-oriented superlattices based on ortho-nickelates.

  9. Strain relaxation and enhanced perpendicular magnetic anisotropy in BiFeO{sub 3}:CoFe{sub 2}O{sub 4} vertically aligned nanocomposite thin films

    SciTech Connect

    Zhang, Wenrui; Jiao, Liang; Li, Leigang; Jian, Jie; Khatkhatay, Fauzia; Chu, Frank; Chen, Aiping; Jia, Quanxi; MacManus-Driscoll, Judith L.; Wang, Haiyan

    2014-02-10

    Self-assembled BiFeO{sub 3}:CoFe{sub 2}O{sub 4} (BFO:CFO) vertically aligned nanocomposite thin films have been fabricated on SrTiO{sub 3} (001) substrates using pulsed laser deposition. The strain relaxation mechanism between BFO and CFO with a large lattice mismatch has been studied by X-ray diffraction and transmission electron microscopy. The as-prepared nanocomposite films exhibit enhanced perpendicular magnetic anisotropy as the BFO composition increases. Different anisotropy sources have been investigated, suggesting that spin-flop coupling between antiferromagnetic BFO and ferrimagnetic CFO plays a dominant role in enhancing the uniaxial magnetic anisotropy.

  10. Crystal structure and ferroelectric properties of rare-earth substituted BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Uchida, Hiroshi; Ueno, Risako; Funakubo, Hiroshi; Koda, Seiichiro

    2006-07-01

    The influence of ion modification using rare-earth cations on crystal structures, along with the insulating and ferroelectric properties of BiFeO3 (BFO) thin films was investigated. Rare-earth-substituted BFO films with chemical compositions of (Bi1.00-xREx)Fe1.00O3 (x =0-0.15, RE =La and Nd) were fabricated on (111)Pt/TiO2/SiO2/(100)Si substrates using a chemical solution deposition technique. A crystalline phase of rhombohedral BFO was obtained by heat treatment in a N2 atmosphere at 500°C for 5min. The crystal anisotropy and the Curie temperature of BFO were degraded continuously with increasing contents of La3+ or Nd3+ cations. Ion modification using La3+ and Nd3+ cations up to x =0.05 lowered the leakage current density of the BFO film at room temperature from approximately 10-3 down to 10-6A/cm2. A polarization (P)-electrical field (E) hysteresis loop measured at 10K revealed that the intrinsic remanent polarization of La3+- and Nd3+-substituted BFO films with x =0.05 (44 and 51μC/cm2, respectively) was smaller than that of a nonsubstituted BFO film (79μC/cm2), which is ascribed to the degradation of crystal anisotropy and the Curie temperature of the BFO crystal.

  11. Ferroelectric BiFeO3 thin-film optical modulators

    NASA Astrophysics Data System (ADS)

    Zhu, Minmin; Du, Zehui; Liu, Qing; Chen, Bensong; Tsang, Siu Hon; Teo, Edwin Hang Tong

    2016-06-01

    High quality epitaxial BiFeO3 (BFO) thin films have been grown on (001) SrTiO3 substrate by magnetron sputtering. Both a-axis and c-axis BFO orientations were studied. Prism coupler results reveal that the c-axis and a-axis refractive indices of the BFO thin films were 2.721 and 2.653 at 632.8 nm; the corresponding propagation losses were 4.3 and 4.6 dB/cm, respectively. An electro-optic (EO) modulator based on such BFO film has been demonstrated with a fast switching time t = 3.8 μs at 632.8 nm for the a-axis orientation and t = 3.4 μs for the c-axis orientation. Moreover, these BFO films gave the Pockels coefficient reff = 19.3 pm/V for the c-axis orientation and reff = 15.9 pm/V for the a-axis orientation at 632.8 nm. Such an anisotropic refractive index and linear EO behaviors are attributed to the epitaxial strain and stripe domain structure in the BFO thin films with mixed phases. This study illustrates the suitability of the BFO thin films for EO modulators and optical switches beyond their current extensive spintronic and memory applications.

  12. Controllable growth of ultrathin BiFeO3 from finger-like nanostripes to atomically flat films

    NASA Astrophysics Data System (ADS)

    Feng, Yu; Wang, Can; Tian, Shilu; Zhou, Yong; Ge, Chen; Guo, Haizhong; He, Meng; Jin, Kuijuan; Yang, Guozhen

    2016-09-01

    BiFeO3 (BFO) ultrathin films with nominal thicknesses from 2 to 12 nm were grown with a SrRuO3 (SRO) buffer layer on TiO2-terminated (001) SrTiO3 (STO) substrates using pulsed laser deposition. The surface morphologies and domain configurations of the thin films were investigated using atomic force microscopy and piezoelectric force microscopy. Periodical one-dimensional finger-like nanostripes of BFO on the SRO covered STO substrates were observed. With increasing thickness, the BFO ultrathin films develop from the finger-like nanostripes to an atomically flat surface. The formation of the finger-like nanostructures of BFO is related to the atomic step or terrace structure of the substrate. The BFO nanostripes and the atomically flat thin films both show good ferroelectricity. The as-grown domain orientations of the BFO ultrathin films are ascribed to the chemical terminations at the surface of the SRO layer. These results indicate that the surface morphologies and the domain configurations of BFO ultrathin films can be artificially designed by using substrates with optimized terrace structures and chemical termination, and these films are potentially useful in multifunctional nanoelectronic devices.

  13. Controllable growth of ultrathin BiFeO3 from finger-like nanostripes to atomically flat films.

    PubMed

    Feng, Yu; Wang, Can; Tian, Shilu; Zhou, Yong; Ge, Chen; Guo, Haizhong; He, Meng; Jin, Kuijuan; Yang, Guozhen

    2016-09-01

    BiFeO3 (BFO) ultrathin films with nominal thicknesses from 2 to 12 nm were grown with a SrRuO3 (SRO) buffer layer on TiO2-terminated (001) SrTiO3 (STO) substrates using pulsed laser deposition. The surface morphologies and domain configurations of the thin films were investigated using atomic force microscopy and piezoelectric force microscopy. Periodical one-dimensional finger-like nanostripes of BFO on the SRO covered STO substrates were observed. With increasing thickness, the BFO ultrathin films develop from the finger-like nanostripes to an atomically flat surface. The formation of the finger-like nanostructures of BFO is related to the atomic step or terrace structure of the substrate. The BFO nanostripes and the atomically flat thin films both show good ferroelectricity. The as-grown domain orientations of the BFO ultrathin films are ascribed to the chemical terminations at the surface of the SRO layer. These results indicate that the surface morphologies and the domain configurations of BFO ultrathin films can be artificially designed by using substrates with optimized terrace structures and chemical termination, and these films are potentially useful in multifunctional nanoelectronic devices. PMID:27454488

  14. Effects of water absorption of dielectric underlayers on Al-Si-Cu film properties and electromigration performance in Al-Si-Cu/Ti/TiN/Ti interconnects

    NASA Astrophysics Data System (ADS)

    Yoshida, Tomoyuki; Hashimoto, Shoji; Ohwaki, Takeshi; Mitsushima, Yasuichi; Taga, Yasunori

    1998-01-01

    The effects of underlying dielectric (phosphosilicate glass and borophosphosilicate glass) films to a humid air ambient on Al-Si-Cu film properties and electromigration (EM) performance in Al-Si-Cu/Ti/TiN/Ti layered films have been investigated as a function of the boron content and exposure time of the dielectric films. The Al(111) orientation in the layered films was found to improve drastically with increasing boron content and exposure time. The full width at half maximum value of an Al(111) x-ray rocking curve reached less than 1°. It was also found that the Al-Si-Cu surface becomes smoother and grain sizes increase as the Al(111) orientation improves. The improved Al(111) orientation was attributed to the improved Ti(002) orientation of the bottom Ti films. Further, it was demonstrate that interconnects fabricated from the improved layered film have excellent EM performance.

  15. Thin film bismuth iron oxides useful for piezoelectric devices

    DOEpatents

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  16. Preferential Crystal Growth of (100)-Oriented BiFeO3 Films on Si Substrate

    NASA Astrophysics Data System (ADS)

    Hayashi, M.; Yasui, S.; Funakubo, H.; Uchida, H.

    2011-10-01

    Bi-based perovskite-type oxide materials such as BiFeO3 (BFO) and the related compounds receive much attention and have been developed actively as important candidates for Pb-free ferroelectric / piezoelectric materials instead of toxic Pb-based perovskite oxide materials. Recently, many researches have been reported for thin films of BFO by various film-deposition techniques for actual application of semiconductive devices, microactuators, etc. In this report, we tried preferential crystal growth of BFO films on semiconductive silicon substrates using uniaxial-(100)-oriented LaNiO3 (LNO) buffer layer. BFO films were fabricated via chemical solution deposition (CSD) technique on platinized silicon wafer [(111)Pt/TiO2/(100)Si] and (100)LNO-coated platinized silicon [(100)LNO/(111)Pt/TiO2/(100)Si] substrates. XRD analysis indicated that the films fabricated on (111)Pt/TiO2/(100)Si substrate consisted of randomly-oriented BFO crystal with lower crystallinity and trace amount of the second Bi2Fe4O9 phase. On the other hand, the films on (100)LNO/(111)Pt/TiO2/(100)Si consisted of uniaxial-(100)-oriented BFO crystal with higher crystallinity. The crystallization temperature these films were 450 and 400°C, respectively. These results suggest that the BFO crystal was grown epitaxially on uniaxial oriented (100)LNO plane which also had perovskite-type crystal structure. Consequently, (100)-oriented BFO films were prepared on Si substrate successfully using (100)LNO buffer layer.

  17. Electronic correlation effects in SrRuO3 ultra-thin films

    NASA Astrophysics Data System (ADS)

    Si, Liang; Zhong, Zhicheng; Janson, Oleg; Li, Gang; Tomczak, Jan; Held, Karsten; Computational Materials Science Team; Electronic Structure Of Correlated Materials Team

    SrRuO3 (SRO) is a ferromagnetic metal with an appreciably high Curie-temperature of 160 K and a ferromagnetic moment of 0.8-1.6 uB/Ru. Recent experimental studies on SRO thin films show that both electronic and magnetic ground states drastically depend on the nature of the surface. Ultra-thin (001)-oriented films are insulating and lack ferromagnetism, while in (111)-oriented films ferromagnetic moments and Tc are enhanced compared with bulk. Here we investigate SRO films by density functional theory (DFT)+U and DFT+dynamical mean-field theory (DMFT). In agreement with the experiments, we find that metallic ferromagnetism in SRO (001)-oriented films vanishes below a certain critical layer thickness. We propose a new route for tuning the properties of these thin films and show that room temperature ferromagnetism can be attained by electron doping. For the SRO (111)-oriented thin films, we find that the enhanced Tc is facilitated by electronic correlation effects and the geometric confinement. The experimentally observed enhancement of ferromagnetic moments in SRO(111)-oriented thin films is addressed by considering the stability of the high-spin Ru state in the presence of oxygen vacancies. Finally, the topological properties of SRO (111)-oriented bilayers will be discussed.

  18. Effect of bottom electrodes on nanoscale switching characteristics and piezoelectric response in polycrystalline BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Yan, F.; Zhu, T. J.; Lai, M. O.; Lu, L.

    2011-10-01

    We have investigated the nanoscale switching characteristics and piezoelectric response based on polycrystalline BiFeO3 (BFO) thin films with different orientations deposited on different oxide bottom electrodes. The BFO film deposited on the LaNiO3 (LNO)-coated Si substrate shows a (001) preferred orientation and higher ferroelectric properties, while the BFO film grown on the SrRuO3 (SRO) buffered Si substrate shows a random orientation. The domain structures have been determined via piezoresponse force microscopy (PFM) for both films, predicting that the BFO film with the LNO bottom electrode has a larger piezoelectricity property corresponding to the ferroelastic domain. Through local switching spectroscopy measurements, the evidence of ferroelectric switching and the origin of the enhanced piezoresponse properties have been provided. A greatly improved piezoelectric response has been demonstrated using PFM that is 66.8 pm V-1 for the BFO with a SRO bottom electrode, while we obtain a value of 348.2 pm V-1 for the BFO with a LNO bottom electrode due to the increased density of the polarization vectors along the external electrical field.

  19. Effect of substrates on magnetization of BiFeO3 films

    NASA Astrophysics Data System (ADS)

    Xu, Tingting; Kan, Yi; Jin, Yaming; Lu, Xiaomei; Wu, Huarui; He, Ju; Lu, Xueliang; Zhu, Weili; Huang, Fengzhen; Zhu, Jinsong

    2015-08-01

    BiFeO3 (BFO) films were fabricated on Pt/Ti/SiO2/Si and single crystalline LiNbO3 (LN) substrates using metal organic decomposition method and annealed in N2/O2. Magnetizations of these films were systematically characterized. It is found that BFO films prepared on Pt/Ti/SiO2/Si substrates exhibit stronger saturation magnetization (MS) than those prepared on LN substrates, and their magnetizations rely more on annealing atmosphere. We consider that both oxide feature of LN substrates and in-plane compressive stress introduced by LN reduce the Fe2+ content in the top BFO films and further stabilize the films against post-treatment. This work provides a valuable guidance for fabricating high quality magnetic oxide films.

  20. Dislocations in mismatched layers of GaAsxP1 - x in between GaP as observed by low-temperature cathodoluminescence: Part II. Grown on (111) oriented substrates

    NASA Astrophysics Data System (ADS)

    Gustafsson, A.; Pistol, M.-E.; Gerling, M.; Samuelson, L.; Titze, H.

    1991-08-01

    Spectrally resolved low-temperature cathodoluminescence (CL) imaging has been performed on thin, 250 Å, mismatched layers of GaAsxP1-x in between bulk GaP. The layers were grown on (111) oriented substrates by metalorganic vapor phase epitaxy, with layers ranging from perfectly strained to totally relaxed. CL imaging has proven to be a very sensitive technique for the study of the onset of the formation of misfit dislocations and is therefore useful for determination of the critical thickness [A. Gustafsson, M.-E. Pistol, M. Gerling, L. Samuelson, M. R. Leys and H. Titze, J. Appl. Phys. 70, 1660 (1991)]. For the use of perfectly strained layers, growth on (111) oriented substrates can be of interest since the critical thickness predicted by the mechanical equilibrium theory [J. W. Matthews and A. E. Blakeslee, J. Cryst. Growth 27, 118 (1974)] is about twice that for growth on (001) oriented substrates. In this work we show that the dislocations involved in the strain relief for the growth of mismatched layers on (111) oriented substrates are of the perfect 60° type and that the experimental critical thickness agrees well with the value expected from the mechanical equilibrium theory.

  1. Large irreversible non-180° domain switching after poling treatment in Pb(Zr, Ti)O3 films

    NASA Astrophysics Data System (ADS)

    Ehara, Yoshitaka; Yasui, Shintaro; Oikawa, Takahiro; Shiraishi, Takahisa; Oshima, Naoya; Yamada, Tomoaki; Imai, Yasuhiko; Sakata, Osami; Funakubo, Hiroshi

    2016-05-01

    (11 1 ¯ )/(111)-oriented rhombohedral Pb(Zr0.65Ti0.35)O3 films with different domain fractions were epitaxially grown on various single crystals. The volume fraction of (111)-polar-axis oriented domains in as-deposited films, Vpol.(as-depo.), was controlled by selecting a single crystal substrate with a different thermal expansion coefficient. Applying an electric field, referred to as "poling treatment", resulted in irreversible non-180° domain switching from the (11 1 ¯ )-oriented domain (non-polar-axis) to the (111)-oriented domain (polar-axis), which was observed by synchrotron X-ray diffraction. Remanent polarization (Pr) values were higher than those estimated using the proportional relationship with Vpol.(as-depo.). However, the experimental Pr values were in good agreement with the values estimated using the volume fraction of (111)-oriented domains after applying the poling treatment. In rhombohedral Pb(Zr0.65Ti0.35)O3 films, 30%-50% of the (11 1 ¯ )-oriented domains switched irreversibly to (111)-oriented domains as a result of the poling treatment. The present results show that the domain structures of films may change dramatically after the poling process, and both before and after the poling state should be characterized in order to interpret polarization and piezoelectric behaviors. This study helps to clarify the ferroelectric and piezoelectric properties of Pb(Zr, Ti)O3 films after poling treatment.

  2. Structural and nanomechanical properties of BiFeO3 thin films deposited by radio frequency magnetron sputtering

    PubMed Central

    2013-01-01

    The nanomechanical properties of BiFeO3 (BFO) thin films are subjected to nanoindentation evaluation. BFO thin films are grown on the Pt/Ti/SiO2/Si substrates by using radio frequency magnetron sputtering with various deposition temperatures. The structure was analyzed by X-ray diffraction, and the results confirmed the presence of BFO phases. Atomic force microscopy revealed that the average film surface roughness increased with increasing of the deposition temperature. A Berkovich nanoindenter operated with the continuous contact stiffness measurement option indicated that the hardness decreases from 10.6 to 6.8 GPa for films deposited at 350°C and 450°C, respectively. In contrast, Young's modulus for the former is 170.8 GPa as compared to a value of 131.4 GPa for the latter. The relationship between the hardness and film grain size appears to follow closely with the Hall–Petch equation. PMID:23799923

  3. Effect of RF power on structural and magnetic properties of La doped Bi2Fe4O9 thin films

    NASA Astrophysics Data System (ADS)

    Santhiya, M.; Pugazhvadivu, K. S.; Balakrishnan, L.; Tamilarasan, K.

    2016-05-01

    Effect of RF power on structural and magnetic properties of lanthanum (La3+) doped Bi2Fe4O9 thin films grown on p-Si substrates by radio frequency (RF) magnetron sputtering has studied in this investigation. It is observed that the sputtering power affects the crystalline nature and magnetic properties of grown thin films. X-ray diffraction and Raman spectrum confirms that the Bi2Fe4O9 (BFO) thin films were crystallized well with orthorhombic structure. The BFO thin films which was prepared at sputtering power of 100 W have good crystallinity than those prepared at 40 W. The magnetic properties are investigated by vibrating sample magnetometer. The magnetic hysteresis perceptive loop shows that the anti-ferromagnetic behavior of the sample at room temperature. These results confirms that the crystallinity and magnetic properties of the BFO thin films were enhanced at the higher sputtering power (100 W).

  4. Magnetic behaviour of sol-gel driven BiFeO3 thin films with different grain size distribution

    NASA Astrophysics Data System (ADS)

    Sharma, Shiwani; Saravanan, P.; Pandey, O. P.; Vinod, V. T. P.; Černík, Miroslav; Sharma, Puneet

    2016-03-01

    BiFeO3 (BFO) thin films with uniform thickness of ~200 nm were prepared by the sol-gel assisted spin coating method. Different grain size distributions in the as-grown BFO films were then induced by varying the annealing temperature between 525 and 600 °C. It is found that the grain size distribution become wider as the annealing temperature increases. All the films showed a well-saturated magnetization (M) versus magnetic field (H) hysteresis loops at 300 K. A strong dependence of M on the grain size distribution is observed. An optimal grain size distribution with average grain size ~90 nm is responsible for high M in the BFO films. The non-saturated M-H loops obtained at 10 K suggest the spin glass behaviour of BFO films. The zero field cooled (ZFC) and field cooled (FC) magnetization curves shows split at 300 K and a cusp at ~50 K in the ZFC curve, which further confirms the spin glass state of polycrystalline BFO thin films.

  5. Evaluation of Crystal Orientation for (K,Na)NbO3 Films Using X-ray Diffraction Reciprocal Space Map and Relationship between Crystal Orientation and Piezoelectric Coefficient

    NASA Astrophysics Data System (ADS)

    Shibata, Kenji; Suenaga, Kazufumi; Watanabe, Kazutoshi; Horikiri, Fumimasa; Mishima, Tomoyoshi; Shiratani, Masaharu

    2012-07-01

    We have found an effective method for the evaluation of the crystal orientation of (K,Na)NbO3 (KNN) films in the (K,Na)NbO3/Pt/Ti/SiO2/Si structure using X-ray diffraction (XRD) reciprocal space maps. Previously, the crystal structure and orientation of such (K,Na)NbO3 films were evaluated using 2θ/θ XRD, and were considered to be the pseudocubic perovskite structure with preferential (001) orientation and no (111) orientation. Here, we applied the new method using XRD reciprocal space maps, and discovered that the (K,Na)NbO3 films had some degree of KNN(111) orientation. We calculated the KNN(001)- and KNN(111)-orientation volume fractions for the (K,Na)NbO3 films from the (101) diffraction peaks originating from the KNN(001)- and KNN(111)-orientation elements in the XRD reciprocal space maps, considering the calibration factors obtained from pole-figure simulations, and examined the relationship between the crystal orientation and d31 piezoelectric coefficient in the (K,Na)NbO3 films. The results indicated that the d31 piezoelectric coefficient increases with increasing (001)-orientation volume fraction.

  6. Domain switching in spray pyrolysis-deposited nano-crystalline BiFeO3 films

    NASA Astrophysics Data System (ADS)

    Annapu Reddy, V.; Pathak, N. P.; Nath, R.

    2012-12-01

    Single-phase nano-scale BiFeO3 (BFO) films have been prepared under a controlled substrate temperature by a simple spray pyrolysis method. Fourier-transform infrared spectroscopy results indicate that single-phase BFO is deposited at low temperature. A magnetoelectric coupling to the anti-ferromagnetic and α-β phase transitions was observed at 350.2 and 832.8 °C, respectively. The capacitance-voltage (C-V) curves exhibit two coercive fields corresponding to ferroelastic (71° and 109°) and ferroelectric (180°) domains. Ferroelectric domain switching is dominant at lower electric fields. A non-volatile domain switching in the BFO films can prevent domain wall pinning and can enhance fatigue behavior in the films.

  7. Observation of three crystalline layers in hydrothermally grown BiFeO{sub 3} thick films

    SciTech Connect

    Lee, T. K.; Sung, K. D.; Jung, J. H.; Kim, T. H.; Ko, J.-H.

    2014-11-21

    We report the observation of three different crystalline layers in hydrothermally grown BiFeO{sub 3} (BFO) thick films on SrRuO{sub 3}/SrTiO{sub 3} substrates. High-resolution X-ray diffraction and transmission electron microcopy results suggest that compressively strained, partially relaxed epitaxial layers, and a mixture of polycrystalline and amorphous BFO layers, were successively formed from the bottom to the top of the films. The resistance and capacitance of the mixed layer were significantly lower than those of the epitaxial layers. The atomic concentrations of Bi and Fe in the mixed layer were fluctuating for each point. Based on the observed three crystalline layers, we have discussed the growth mechanism and the leakage current of hydrothermally grown BFO thick films.

  8. Multiferroic properties of stretchable BiFeO3 nano-composite film

    NASA Astrophysics Data System (ADS)

    Hwang, J. S.; Cho, J. Y.; Park, S. Y.; Yoo, Y. J.; Yoo, P. S.; Lee, B. W.; Lee, Y. P.

    2015-02-01

    We present a simple drop-casting method for preparing multiferroic nano-composite film where BiFeO3 (BFO) nanoparticles (NPs) were evenly dispersed into polyvinyl alcohol (PVA) polymer. BFO NPs used in this work were synthesized by the conventional sol-gel method, having diameter of tens of nm and being in good crystallinity. The BFO NPs were loaded into a highly insulating PVA polymer solution as filler. The multiferroic properties of the film reveal ferromagnetic ordering due to the uncompensated spiral ordering and saturated ferroelectric curves due to the cut-off of current leakage. Moreover, the prepared films show high flexibility and their multiferroicities are preserved well even in a high curved condition, reflecting the possibility for fabricating wearable devices based on multiferroic materials.

  9. Enhanced ferroelectric photoelectrochemical properties of polycrystalline BiFeO3 film by decorating with Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Qing; Zhou, Yang; You, Lu; Wang, Junling; Shen, Mingrong; Fang, Liang

    2016-01-01

    Polycrystalline BiFeO3 (BFO) films are fabricated on Pt/Ti/SiO2/Si(100) substrate as photoelectrode using sol-gel method. The microstructure, optical, and photoelectrochemical (PEC) properties of the films are characterized and optimized by controlling the film thickness. Moreover, the PEC properties of the BFO films are dependent on ferroelectric polarization, which is mainly ascribed to the modulation of band structure at the BFO/electrolyte interface by the polarization. Further enhancement of PEC properties is obtained by decorating the samples with appropriate amounts of Ag nanoparticles, which is attributed to the reduced electron-hole recombination, and localized surface plasmon resonance effect of Ag nanoparticles.

  10. Low-temperature (180 °C) formation of large-grained Ge (111) thin film on insulator using accelerated metal-induced crystallization

    SciTech Connect

    Toko, K. Numata, R.; Oya, N.; Suemasu, T.; Fukata, N.; Usami, N.

    2014-01-13

    The Al-induced crystallization (AIC) yields a large-grained (111)-oriented Ge thin film on an insulator at temperatures as low as 180 °C. We accelerated the AIC of an amorphous Ge layer (50-nm thickness) by initially doping Ge in Al and by facilitating Ge diffusion into Al. The electron backscatter diffraction measurement demonstrated the simultaneous achievement of large grains over 10 μm and a high (111) orientation fraction of 90% in the polycrystalline Ge layer formed at 180 °C. This result opens up the possibility for developing Ge-based electronic and optical devices fabricated on inexpensive flexible substrates.

  11. Orientation-controlled nonepitaxial L1{sub 0} FePt thin films

    SciTech Connect

    Dang, Honggang; Liu, Liwang; Hao, Liang; Jin, Tianli; Liu, Mingfeng; Cao, Jiangwei Bai, Jianmin; Wang, Ying; Wei, Fulin

    2014-05-07

    We report an orientation-controlled FePt thin films grown nonexpitaxially on oxidized Si substrates without using any underlayers. After 700 °C annealing, the FePt single layer with thickness less than 10 nm shows good (001) texture and perpendicular anisotropy. The scanning electron microscope images indicate that these films are composed of isolated islands. For the films thicker than 20 nm, the films become continuous and (111) orientation appears. The transition of film texture relates to the change of morphology of the films. Finally, a theoretical mode based on minimizing surface energy is proposed to explain the texture variation in the films.

  12. Temperature dependent dielectric and ferroelectric studies of BiFeO3 thin film

    NASA Astrophysics Data System (ADS)

    Gaur, Anand P. S.; Barik, Sujit K.; Katiyar, Ram S.

    2013-03-01

    Although BiFeO3 (BFO) has received a lot of interest due to its good multiferroic properties at room temperature, high leakage current limit its usage for practical applications. Recently, it is found that these properties in thin films can be different due to strain effect induced by substrate, preparation conditions and electrode effects, etc. In this context, we have studied the temperature dependence of polarization and dielectric properties of BFO thin film by varying the bottom electrode thickness and using different electrodes. The strain dependent ferroelectric switching behaviors have also been investigated with a traditional ferroelectric tester and switching spectroscopy piezoresponse force microscopy (SS-PFM), respectively. We used pulsed laser deposition to fabricate thin films of BFO using Si (100) substrate and SrTiO3(STO) as buffer layer with different bottom electrodes such as SrRuO3(SRO), LaNiO3(LNO) and Pt/Si. The thickness of STO layer is kept fixed around 70 nm and the thicknesses of BFO and electrode layer were varied from 70 nm to 200nm. The layers were grown under optimized conditions and polycrystalline nature is found from room temperature XRD. A large enhancement of polarization is found while using LNO electrode and also with reducing the thickness of BFO layer. The remnant polarization and cohesivity also shows large increase with increaisng temperature, although leakage current increases significantly. NSF

  13. Effect of top electrodes on photovoltaic properties of polycrystalline BiFeO3 based thin film capacitors

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Li, Mi; Liu, Yiwei; Zuo, Zhenghu; Zhuge, Fei; Zhan, Qing-Feng; Li, Run-Wei

    2011-05-01

    We investigated capacitors based on polycrystalline narrow-band-gap BiFeO3 (BFO) thin films with different top electrodes. The photovoltaic response for the capacitor with a Sn-doped In2O3 (ITO) top electrode is about 25 times higher than that with a Au top electrode, which indicates that the electrode plays a key role in determining the photovoltaic response of ferroelectric thin film capacitors, as simulated by Qin et al (2009 Appl. Phys. Lett. 95 22912). The light-to-electricity photovoltaic efficiency for the ITO/polycrystalline BFO/Pt capacitor can reach 0.125%. Furthermore, under incident light of 450 µW cm - 2 and zero bias, the corresponding photocurrent varies from 0.2 to 200 pA, that is, almost a 1000-fold photoconductivity enhancement. Our experiments suggest that polycrystalline BFO films are promising materials for application in photo-sensitive and energy-related devices.

  14. Nanoscale Mapping of the Magnetic Properties of (111)-Oriented La(0.67)Sr(0.33)MnO3.

    PubMed

    O'Shea, Kerry J; MacLaren, Donald A; McGrouther, Damien; Schwarzbach, Danny; Jungbauer, Markus; Hühn, Sebastian; Moshnyaga, Vasily; Stamps, Robert L

    2015-09-01

    Spatially resolved analysis of magnetic properties on the nanoscale remains challenging, yet strain and defects on this length-scale can profoundly affect a material's bulk performance. We present a detailed investigation of the magnetic properties of La0.67Sr0.33MnO3 thin films in both free-standing and nanowire form and assess the role of strain and local defects in modifying the films' magnetic properties. Lorentz transmission electron microscopy is used to measure the magnetocrystalline anisotropy and to map the Curie temperature and saturation magnetization with nanometric spatial resolution. Atomic-scale defects are identified as pinning sites for magnetic domain wall propagation. Measurement of domain wall widths and crystalline strain are used to identify a strong magnetoelastic contribution to the magnetic anisotropy. Together, these results provide unique insight into the relationship between the nanostructure and magnetic functionality of a ferromagnetic complex oxide film. PMID:26252745

  15. Effect of epitaxial strain on magnetization and photo-control of spontaneous polarization in BiFeO3 films on (LaAlO3)0.3(Sr2AlTaO6)0.7(110) substrate

    NASA Astrophysics Data System (ADS)

    Rana, D. S.; Kawayama, I.; Murakami, H.; Tonouchi, M.

    2008-03-01

    Recent researches on thin films of BiFeO3 have been driven by the need to obtain better multiferroic properties by either inducing epitaxial strain or fabrication of magnetoelectric superlattices. The BFO (100) thin films on (LaAlO3)0.3(Sr2AlTaO6)0.7 (100) substrate are highly strained with different physical properties than that of bulk [1]. Given the dependence of ferroelectric polarization of BFO on crystallographic directions, epitaxial thin films -- 70nm and 180nm - of BFO were deposited on LSAT (110) substrate. Structure and surface morphology of BFO/LSAT(110) films show that the films with thickness <= 80 nm possess a strong in-plane strain while thicker films (150-200nm) are partially relaxed with a bulklike structure. Though the magnetic properties of BFO/LSAT(110) films are nearly independent of structure, the spontaneous polarization and the ferroelectric properties (probed by terahertz emission) are strong characteristic of structure. These results emphasize the importance of epitaxial strain induced tailoring of the ferroelectric properties of BiFeO3 film along (110) crystallographic direction. 1. D.S. Rana et al, Phys. Rev. B 75, 060405 (2007).

  16. Epitaxial growth of (111)-oriented BaTiO{sub 3}/SrTiO{sub 3} perovskite superlattices on Pt(111)/Ti/Al{sub 2}O{sub 3}(0001) substrates

    SciTech Connect

    Panomsuwan, Gasidit; Takai, Osamu; Saito, Nagahiro

    2013-09-09

    Symmetric BaTiO{sub 3}/SrTiO{sub 3} (BTO/STO) superlattices (SLs) were epitaxially grown on Pt(111)/Ti/Al{sub 2}O{sub 3}(0001) substrates with various modulation periods (Λ = 4.8 − 48 nm) using double ion beam sputter deposition. The BTO/STO SLs exhibit high (111) orientation with two in-plane orientation variants related by a 180° rotation along the [111]{sub Pt} axis. The BTO layer is under an in-plane compressive state, whereas the STO layer is under an in-plane tensile state due to the effect of lattice mismatch. A remarkable enhancement of dielectric constant is observed for the SL with relatively small modulation period, which is attributed to both the interlayer biaxial strain effect and the Maxwell-Wagner effect.

  17. Exchange bias and crystal structure of epitaxial (111) FePt/BiFeO{sub 3} sputtered thin films

    SciTech Connect

    Chiu, Shang-Jui; Hsiao, Shih-Nan Lee, Hsin-Yi; Huang, Li-Chun; Yu, Ge-Ping; Chang, Huang-Wei

    2014-05-07

    Crystallographic structure and magnetic properties of the epitaxial FePt (10 nm)/BiFeO{sub 3} (BFO) (10 nm) bilayer films grown on (111) SrTiO{sub 3} (STO) substrates with different deposition temperatures of FePt layers (T{sub d}) have been investigated using magnetron sputtering. Out-of-plane radial scan along (111) direction and off-normal (002) azimuthal scan, determined by synchrotron radiation x-ray diffractometry, evidence that the FePt layers were well epitaxially grown on the (111) epitaxial BFO layers for the samples with T{sub d} = 300 and 700 °C. On the contrary, for the bilayer films with T{sub d} = 500 °C, the FePt and BFO layers exhibit low epitaxial quality. Large in-plane exchange bias field (H{sub eb}) values of 45–412 Oe are obtained for the L1{sub 0}-FePt/BFO bilayer films measured with applied field of 12 kOe at room temperature. The change of effective interfacial area, observed by scanning electron microscopy, between FePt island-like particles and BFO continuous layers, and epitaxiality of the bilayer were correlated with the evolution of H{sub eb}.

  18. Orientation and thickness dependence of magnetization at the interfacesof highly spin-polarized manganite thin films

    SciTech Connect

    Chopdekar, Rajesh V.; Arenholz, Elke; Suzuki, Y.

    2008-08-18

    We have probed the nature of magnetism at the surface of (001), (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films. The spin polarization of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films is not intrinsically suppressed at all surfaces and interfaces but is highly sensitive to both the epitaxial strain state as well as the substrate orientation. Through the use of soft x-ray spectroscopy, the magnetic properties of (001), (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interfaces have been investigated and compared to bulk magnetometry and resistivity measurements. The magnetization of (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interfaces are more bulk-like as a function of thickness whereas the magnetization at the (001)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interface is suppressed significantly below a layer thickness of 20 nm. Such findings are correlated with the biaxial strain state of the La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films; for a given film thickness it is the tetragonal distortion of (001) La{sub 0.7}Sr{sub 0.3}MnO{sub 3} that severely impacts the magnetization, whereas the trigonal distortion for (111)-oriented films and monoclinic distortion for (110)-oriented films have less of an impact. These observations provide evidence that surface magnetization and thus spin polarization depends strongly on the crystal surface orientation as well as epitaxial strain.

  19. Ferroelectric and ferromagnetic properties of epitaxial BiFeO{sub 3}-BiMnO{sub 3} films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    SciTech Connect

    Xiong, J.; Matias, V.; Jia, Q. X.; Tao, B. W.; Li, Y. R.

    2014-05-07

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO{sub 3}){sub 0.5}:(BiMnO{sub 3}){sub 0.5} [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9 μC/cm{sup 2}. The magnetization of the BFO-BMO/LSMO is 62 emu/cc at room temperature.

  20. Control of oxygen octahedral rotation in BiFeO3 films using modulation of SrRuO3 bottom electrode layer

    NASA Astrophysics Data System (ADS)

    Lee, Sungsu; Jo, Ji Young

    2015-03-01

    Oxygen octahedral rotation of multiferroic BiFeO3 (BFO) has attracted great attention due to changes of electrical and magnetic properties. Coupling of octahedral rotation in BFO-bottom electrode layer interface remains unexplored. Recently, there have been reported the control of octahedral rotation in SrRuO3 (SRO) film on SrTiO3 (001) substrate by coherently controlling the oxygen pressure during growth and interfacial coupling. Here we demonstrate that the octahedral rotation of BFO film is changed using tetragonal a0a0c- tilted-SRO bottom electrodes. In this work, BFO/SRO heterostructure is fabricated to SrTiO3 (001) single crystal substrates by pulsed laser deposition at different oxygen partial pressures. The rotation pattern of FeO6 and the structural symmetry are identified from half-integer reflections using high-resolution X-ray diffraction. The effects depending on octahedral tilting of BFO films on the magnetic and ferroelectric properties will be presented.

  1. Formation of perovskite BiFeO3(001) films on refined Pt(111) electrode layer with reduced thickness on glass substrates

    NASA Astrophysics Data System (ADS)

    Chang, H. W.; Yuan, F. T.; Tien, S. H.; Tu, K. T.; Wang, C. R.; Jen, S. U.

    2014-05-01

    Structure and ferroelectric properties of multiferroic BiFeO3 (001) films grown on Pt(111) buffer layer with thicknesses of 5-50 nm on glass substrate at 500 °C have been studied. (001) texture of the perovskite BiFeO3 (BFO) could be developed. Grain size and morphology of the BFO(001) films were closely related to those of Pt electrode although no epitaxial growth was evidenced. The optimized BFO layer which exhibited the ferroelectric performance comparable to those with SrRuO3 under layer could be achieved in the samples with Pt thickness in the range of 10 to 20 nm. Different from the polycrystalline BFO/SrRuO3 films, large grain size for 50-nm-thick Pt underlayer causes degeneration of both the ferroelectric properties and the (001)-texture due to the formation of the secondary B2O3 phase. On the other hand, reducing Pt thickness to 5 nm resulted in the induction of the pinholes and thus the increase of the leakage current density. The presented results reveal that a smooth interface between the Pt electrode and BFO layer is essential to achieve good ferroelectric properties.

  2. Manipulating magnetic anisotropy of the ultrathin Co2FeAl full-Heusler alloy film via growth orientation of the Pt buffer layer

    NASA Astrophysics Data System (ADS)

    Wen, F. S.; Xiang, J. Y.; Hao, C. X.; Zhang, F.; Lv, Y. F.; Wang, W. H.; Hu, W. T.; Liu, Z. Y.

    2013-12-01

    The ultrathin films of Co2FeAl (CFA) full-Heusler alloy were prepared between two Pt layers on MgO single crystals by magnetron sputtering. By controlling the substrate temperature, different growth orientations of the Pt underlayers were realized, and their effects were investigated on the magnetic anisotropy of the ultrathin CFA film. It was revealed that different Pt orientations lead to distinctly different magnetic anisotropy for the sandwiched ultrathin CFA films. The Pt (111) orientation favors the perpendicular anisotropy, while the appearance of partial Pt (001) orientation leads to the quick decrease of perpendicular anisotropy and the complete Pt (001) orientation gives rise to the in-plane anisotropy. With the Pt (111) orientation, the temperature and thickness-induced spin reorientation transitions were investigated in the sandwiched ultrathin CFA films.

  3. Characterization of dislocations in germanium layers grown on (011)- and (111)-oriented silicon by coplanar and noncoplanar X-ray diffraction1

    PubMed Central

    Benediktovitch, Andrei; Zhylik, Alexei; Ulyanenkova, Tatjana; Myronov, Maksym; Ulyanenkov, Alex

    2015-01-01

    Strained germanium grown on silicon with nonstandard surface orientations like (011) or (111) is a promising material for various semiconductor applications, for example complementary metal-oxide semiconductor transistors. However, because of the large mismatch between the lattice constants of silicon and germanium, the growth of such systems is challenged by nucleation and propagation of threading and misfit dislocations that degrade the electrical properties. To analyze the dislocation microstructure of Ge films on Si(011) and Si(111), a set of reciprocal space maps and profiles measured in noncoplanar geometry was collected. To process the data, the approach proposed by Kaganer, Köhler, Schmidbauer, Opitz & Jenichen [Phys. Rev. B, (1997 ▶), 55, 1793–1810] has been generalized to an arbitrary surface orientation, arbitrary dislocation line direction and noncoplanar measurement scheme. PMID:26089757

  4. Pinhole-free growth of epitaxial CoSi.sub.2 film on Si(111)

    NASA Technical Reports Server (NTRS)

    Lin, True-Lon (Inventor); Fathauer, Robert W. (Inventor); Grunthaner, Paula J. (Inventor)

    1991-01-01

    Pinhole-free epitaxial CoSi.sub.2 films (14') are fabricated on (111)-oriented silicon substrates (10) with a modified solid phase epitaxy technique which utilizes (1) room temperature stoichiometric (1:2) codeposition of Co and Si followed by (2) room temperature deposition of an amorphous silicon capping layer (16), and (3) in situ annealing at a temperature ranging from about 500.degree. to 750.degree. C.

  5. Optical and grain boundary potential characteristics of sulfurized BiFeO3 thin films for photovoltaic applications.

    PubMed

    Lee, Seung Min; Cho, Yong Soo

    2016-04-01

    Sulfurized BiFeO3 (BFO) thin films have been investigated with the purpose of reducing their band gap for photovoltaic applications. A strong dependence of the degree of sulfurization on the structure and optical properties of the BFO thin films was observed. The sulfurization process substantially reduced the optical band gap from 2.83 eV for the reference sample to ∼1.90 eV in a sample sulfurized at 200 °C, a temperature at which the BFO phase was still dominant. The existence of the secondary Bi2S3 phase was found to be initiated from the film surface and became dominant at higher temperatures. XPS analysis suggests potential Bi-Fe(iii)-Fe(ii)-S-O compounds as a result of the change of the oxidation state of Fe with the progress of sulfurization. The sulfurized BFO film exhibited relatively higher positively charged grain boundaries than the reference film, suggesting its improved applicability in photovoltaic devices. PMID:26918247

  6. Dielectric properties and phase transitions of [001], [110], and [111] oriented Pb(Zn1/3Nb2/3)O3-6%PbTiO3 single crystals

    NASA Astrophysics Data System (ADS)

    Amin Hentati, Mouhamed; Dammak, Hichem; Khemakhem, Hamadi; Pham Thi, Mai

    2013-06-01

    Phase transformations of [001], [110], and [111] oriented Pb(Zn1/3Nb2/3)O3-6%PbTiO3 (PZN-6%PT) single crystals have been investigated by means of dielectric permittivity and loss, x-ray diffraction and depolarization current as function of temperature (from 250 to 500 K). The unpoled samples undergo R-T-C phase transition sequence during zero field heating (ZFH), where R, T, and C are rhombohedral, tetragonal, and cubic phases, respectively. Under electric field (0.5 kV/cm), an intermediate orthorhombic (O) phase is induced between the T and R phases in the field cooling (FC) process. This phase reappears during subsequent zero field heating of the poled sample (zero field heating after field cooling: ZFHaFC). The existence range of this O phase depends on both the crystal orientation and the measurement conditions (FC or ZFHaFC). Finally, for the [001] direction, it was found that the piezoelectric activity of the intermediate phase is the highest.

  7. Effect of annealing atmosphere on phase formation and electrical characteristics of bismuth ferrite thin films

    SciTech Connect

    Simoes, A.Z.; Riccardi, C.S.; Dos Santos, M.L.; Garcia, F. Gonzalez; Longo, E.; Varela, J.A.

    2009-08-05

    Bismuth ferrite thin films were deposited on Pt/Ti/SiO{sub 2}/Si substrates by a soft chemical method and spin-coating technique. The effect of annealing atmosphere (air, N{sub 2} and O{sub 2}) on the structure and electrical properties of the films are reported. X-ray diffraction analysis reveals that the film annealed in air atmosphere is a single-phase perovskite structure. The films annealed in air showed better crystallinity and the presence of a single BFO phase leading to lower leakage current density and superior ferroelectric hysteresis loops at room temperature. In this way, we reveal that BFO film crystallized in air atmosphere by the soft chemical method can be useful for practical applications, including nonvolatile digital memories, spintronics and data-storage media.

  8. Relaxation in photo-induced conductivity of polycrystalline BiFeO3 film

    NASA Astrophysics Data System (ADS)

    Peng, Zengwei; Liu, Baoting

    2015-08-01

    Polycrystalline BiFeO3 (BFO) film is deposited on Pt(1 1 1)/Ti/SiO2/Si(0 0 1) substrate via magnetron sputtering. Integrated Pt/SrRuO3 (SRO) are used to be top electrode to produce the Pt/SRO/BFO/Pt thin film capacitor. The remanent polarization is 59.5, 69.3, 77 and 89.8 μC/cm2 measured at 22.5, 25, 27.5 and 30 V, respectively. The photoconductivity is reported in BFO film under the illumination by the 5 mW/cm2 purple light of 404 nm. It is found that the leakage current density in purple light displays the tendency of decline with the increased illumination times, which can be explained by the recombination and capture of the photo-induced charges by the ionized vacancies. The relaxation time for the illuminated leakage current density reaching the steady state is 210 and 570 s at positive and negative bias, respectively. The obtained large relaxation time at negative bias is considered to be that negative bias is in the same direction as the SRO/BFO interface field.

  9. Growth and characterization of thin oriented Co3O4 (111) films obtained by decomposition of layered cobaltates NaxCoO2

    NASA Astrophysics Data System (ADS)

    Buršík, Josef; Soroka, Miroslav; Kužel, Radomír; Mika, Filip

    2015-07-01

    The formation and structural characterization of highly (111)-oriented Co3O4 films prepared by a novel procedure from weakly (001)-oriented NaxCoO2 is reported. The NaxCoO2 films were deposited on both single crystal and amorphous substrates by chemical solution deposition (CSD) method and crystallized at 700 °C. Subsequently they were transformed into (111)-oriented Co3O4 phase during post-growth annealing at 900 °C. The degree of preferred orientation in Co3O4, which was determined by phi-scan and pole figure measurements, depends on the content of Na in the starting NaxCoO2 phase. Surface morphology of the films was investigated using electron microscopy and atomic force microscopy.

  10. Nanometer scale mechanical properties of Au(111) thin films

    SciTech Connect

    Salmeron, M.; Folch, A.; Neubauer, G.

    1992-11-01

    The mechanical properties of gold films of (111) orientation were studied as a function of load when contacted by a single asperity Pt-Rh alloy tip. The interaction forces were measured in the direction perpendicular to the surface. The contribution of various types of forces (van der Waals, capillarity from contaminants, and metallic adhesion) in the process of contact was determined. We investigated the elastic and plastic response of the gold film as a function of applied load by examination of the contact area in subsequent imaging with STM and AFM.

  11. Structure and magnetic properties of spinel-perovskite nanocomposite thin films on SrTiO3 (111) substrates

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hun; Yang, Junho; Kim, Min Seok; Kim, Tae Cheol

    2016-09-01

    Epitaxial CoFe2O4-BiFeO3 nanocomposite thin films were synthesized on perovskite structured SrTiO3 (001) and (111) substrates by combinatorial pulsed laser deposition and characterized using scanning electron microscopy, x-ray diffraction, and vibrating sample magnetometer. Triangular BiFeO3 nanopillars were formed in a CoFe2O4 matrix on (111) oriented SrTiO3 substrates, while CoFe2O4 nanopillars with rectangular or square top surfaces grew in a BiFeO3 matrix on (001) substrates. The magnetic hysteresis loops of nanocomposites on (111) oriented SrTiO3 substrates showed isotropic properties due to the strain relaxation while those of films on SrTiO3 (001) substrates exhibited a strong out-of-plane anisotropy originated from shape and strain effects.

  12. Direct synthesis of highly textured Ge on flexible polyimide films by metal-induced crystallization

    NASA Astrophysics Data System (ADS)

    Oya, N.; Toko, K.; Saitoh, N.; Yoshizawa, N.; Suemasu, T.

    2014-06-01

    The highly (111)-textured Ge thin film (50-nm thickness) is demonstrated on a flexible polyimide film via the low-temperature crystallization (325 °C) of amorphous Ge using Al as a catalyst. Covering the polyimide with insulators significantly improved the crystal quality of the resulting Ge layer. In particular, SiN covering led to 97% (111)-oriented Ge with grains 200 μm in size, two orders larger than the grain size of polycrystalline Ge directly formed on the polyimide film. This achievement will give a way to realize advanced electronic and optical devices simultaneously allowing for high performance, inexpensiveness, and flexibility.

  13. Direct synthesis of highly textured Ge on flexible polyimide films by metal-induced crystallization

    SciTech Connect

    Oya, N.; Toko, K. Suemasu, T.; Saitoh, N.; Yoshizawa, N.

    2014-06-30

    The highly (111)-textured Ge thin film (50-nm thickness) is demonstrated on a flexible polyimide film via the low-temperature crystallization (325 °C) of amorphous Ge using Al as a catalyst. Covering the polyimide with insulators significantly improved the crystal quality of the resulting Ge layer. In particular, SiN covering led to 97% (111)-oriented Ge with grains 200 μm in size, two orders larger than the grain size of polycrystalline Ge directly formed on the polyimide film. This achievement will give a way to realize advanced electronic and optical devices simultaneously allowing for high performance, inexpensiveness, and flexibility.

  14. Epitaxial growth of Ge-Sb-Te films on KCl by high deposition rate pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Thelander, E.; Gerlach, J. W.; Ross, U.; Frost, F.; Rauschenbach, B.

    2014-06-01

    Pulsed laser deposition was employed to deposit epitaxial Ge2Sb2Te5-layers (GST) on (100) oriented KCl-substrates. XRD-measurements show a process temperature window for epitaxial growth of the cubic phase between 200 and 300 °C. Below 250 °C (111) oriented GST dominates the growth process and above 250 °C the (100) orientation is the dominating one. Pole figure measurements confirm these results and additionally reveal that the (111) orientation consists of 4 domains with 90° azimuthal separation with an initial 15° rotation with the substrate lattice, i.e., [2-1-1]GST || [100]KCl. The (100) orientation grows cube-on-cube with KCl. A systematic variation of the deposition rate showed that it is possible to obtain epitaxial films in the range between 2.5 and 250 nm/min with no significant deterioration of crystal quality. A smooth topography of (111) oriented films was found, whereas the (100) dominated films in general show higher surface roughness as evidenced from atomic force microscopy investigations.

  15. Highly textured Sr, Nb co-doped BiFeO{sub 3} thin films grown on SrRuO{sub 3}/Si substrates by rf- sputtering

    SciTech Connect

    Ostos, C.; Raymond, O.; Siqueiros, J. M.; Suarez-Almodovar, N.; Bueno-Baques, D.; Mestres, L.

    2011-07-15

    In this study, (011)-highly oriented Sr, Nb co-doped BiFeO{sub 3} (BFO) thin films were successfully grown on SrRuO{sub 3}/Si substrates by rf-magnetron sputtering. The presence of parasite magnetic phases was ruled out based on the high resolution x-ray diffraction data. BFO films exhibited a columnar-like grain growth with rms surface roughness values of {approx_equal}5.3 nm and average grain sizes of {approx_equal}65-70 nm for samples with different thicknesses. Remanent polarization values (2P{sub r}) of 54 {mu}C cm{sup -2} at room temperature were found for the BFO films with a ferroelectric behavior characteristic of an asymmetric device structure. Analysis of the leakage mechanisms for this structure in negative bias suggests Schottky injection and a dominant Poole-Frenkel trap-limited conduction at room temperature. Oxygen vacancies and Fe{sup 3+}/Fe{sup 2+} trap centers are consistent with the surface chemical bonding states analysis from x-ray photoelectron spectroscopy data. The (011)-BFO/SrRuO{sub 3}/Si film structure exhibits a strong magnetic interaction at the interface between the multiferroic film and the substrate layer where an enhanced ferromagnetic response at 5 K was observed. Zero-field cooled (ZFC) and field cooled (FC) magnetization curves of this film system revealed a possible spin glass behavior at spin freezing temperatures below 30 K depending on the BFO film thickness.

  16. Reduced leakage in epitaxial BiFeO{sub 3} films following oxygen radio frequency plasma treatment

    SciTech Connect

    Kothari, Deepti; UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 ; Upadhyay, Sanjay K.; Raghavendra Reddy, V.; Jariwala, C.; Raole, P. M.

    2013-06-07

    Epitaxial BiFeO{sub 3} (BFO) films were deposited using pulsed laser deposition method. The prepared films were characterized using x-ray diffraction, x-ray reflectivity, ferroelectric loop tracer, and leakage current measurements before and after oxygen plasma treatment. The leakage current of the films, a crucial parameter in device applications, is observed to be reduced by two orders of magnitude with oxygen plasma treatment at room temperature. P-E hysteresis loops were observed in oxygen plasma treated BFO films. The observed results indicate the usefulness of oxygen radio frequency plasma treatment (RF 13.56 MHz), which is an effective and low temperature processing technique, in such lossy ferroelectric thin films.

  17. Structural and electrical properties of polycrystalline Bi(Fe0.6Mn0.4)O3 thin films

    NASA Astrophysics Data System (ADS)

    Kim, S. W.; Kim, W. J.; Lee, M. H.; Song, T. K.; Do, D.

    2013-12-01

    A 40% Mn-substituted BiFeO3 (BFMO) thin film was deposited on a Pt(111)/Ti/SiO2/Si(100) substrate by using a pulsed laser deposition method. The coexistence of rhombohedral and orthorhombic structures in the BFMO thin film was confirmed by using X-ray diffraction and Raman spectra investigation. The leakage current density of the BFMO thin film was larger than that of a pure polycrystalline BiFeO3 (BFO) thin film. In order to understand the leakage current behaviors, was investigated the leakage current mechanisms. The leakage current mechanism of the BFO thin film was found to be space-charge-limited conduction (SCLC), followed by trap-filled conduction causal by the increasing electric field strength. On the other hand, trap-filled conduction was not observed in the BFMO thin film. A leaky ferroelectric hysteresis loop was observed in the BFMO thin film, but not in the BFO thin film.

  18. Cooperative effect of oxygen-vacancy-rich layer and ferroelectric polarization on photovoltaic properties in BiFeO3 thin film capacitors

    NASA Astrophysics Data System (ADS)

    Matsuo, Hiroki; Kitanaka, Yuuki; Inoue, Ryotaro; Noguchi, Yuji; Miyayama, Masaru

    2016-01-01

    Photovoltaic (PV) properties of ferroelectric SrRuO3/BiFeO3/SrRuO3 (SRO/BFO/SRO) epitaxial thin-film capacitors are investigated. The experimental results of the markedly reduced PV response caused by the doping of Mn provide evidence that the PV properties originate not from the bulk-derived PV effect but from an interfacial band bending. We show that the capacitors having a defective layer composed of oxygen vacancies at the SRO/BFO interface exhibit a markedly large photocurrent. Our study demonstrates that a cooperative effect between the interface charges arising from ferroelectric polarization and the oxygen-vacancy-rich layer enhances the PV response in capacitor form in the BFO system.

  19. Symmetry of Highly-Strained BiFeO3 Films in the Ultrathin Regime

    NASA Astrophysics Data System (ADS)

    Yang, Yongsoo; Senabulya, Nancy; Clarke, Roy; Schlepütz, Christian M.; Beekman, Christianne; Siemons, Wolter; Christen, Hans M.

    2014-03-01

    At room temperature, highly-strained BiFeO3 (BFO) films grown on LaAlO3 substrates exhibit a monoclinic structure with a giant c/a ratio (~1.3) when the films are thicker than 4 nm. Their structural symmetry can be controlled by adjusting the temperature [Appl. Phys. Express 4, 095801 (2011), Adv. Mater. 25, 5561 (2013)], with a high-temperature tetragonal phase being observed. We report that a structural phase transition can also be achieved by controlling the film thickness: synchrotron x-ray diffraction data shows that the Bragg peak splitting associated with the monoclinic phase disappears as the film thickness decreases below 3 nm, indicating a tetragonal symmetry, but still maintaining the giant c/a ratio. Unlike a similar transition reported for moderately strained BFO grown on SrTiO3 [APL Mater. 1, 052102 (2013)], the half-order Bragg peaks indicate that this transition does not involve a significant change in the octahedral tilt pattern of the film. This suggests that the structural evolution of highly-strained BFO films should be understood in terms of the unique (non-octahedral) oxygen coordination of the Fe ion in this highly-strained BFO, not the corner-connectivity of the oxygen octahedra between the film and the substrate. Funding: U.S. Department of Energy, BES-MSED (U. Michigan: DE-FG02-06ER46273, and at ORNL). Measurements: 13-BMC, 33-IDD, 33-BMC of the Advanced Photon Source, ANL (DE-AC02-06CH11357).

  20. Influence of the ion energy on the structure of Bi and Fe2O3 thin films

    NASA Astrophysics Data System (ADS)

    Cardona, Dagoberto; Camps, Enrique; Escobar-Alarcón, L.; Rodil, Sandra E.

    2013-03-01

    Compounds containing bismuth, iron and oxygen (BFO) can result in materials with important magnetic and electrical properties for high-technology applications. We plan to prepare such compounds using the simultaneous ablation of bismuth and iron oxide targets. For that reason in the first part of this work we study the plasmas and the materials produced by ablation of bismuth or Fe2O3 targets, and then the two plasmas are combined in order to deposit the BFO compounds. The individual plasmas were characterized using a Langmuir probe, in order to measure the mean kinetic ion energy ( E p) and plasma density ( N p). Bismuth and magnetite-Fe3O4 thin films were obtained in high vacuum (2.7×10-4 Pa). Meanwhile for the deposition of α-Fe2O3 (hematite) or amorphous bismuth oxide thin films a reactive atmosphere (Ar/O2=80/20) was used. All depositions were made at room temperature. The bismuth thin films crystallized in the rhombohedral metallic system with preferential orientations that depended on the Bi-ion energy used. Bismuth oxide phases were only obtained after annealing of the Bi thin films at different temperatures. Iron oxide thin films reproducing the target stoichiometry were obtained at a certain value of iron-ion energy. Preliminary structural results of the BFO thin films obtained by the combination of the individual plasmas are presented.

  1. Dependence of the ferroelectric properties of modified spin-coating-derived PZT thick films on the crystalline orientation

    NASA Astrophysics Data System (ADS)

    Annapureddy, Venkateswarlu; Choi, Jong-Jin; Kim, Jong-Woo; Hahn, Byung-Dong; Ahn, Cheol-Woo; Ryu, Jungho

    2016-06-01

    The effects of crystalline orientation on the ferroelectric properties of lead zirconate titanate (PZT) thick films deposited on (111)-oriented Pt/Ti/SiO2/Si substrates by using a modified spincoating method have been studied. The texture and the microstructure of the thick films were characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis, respectively. The XRD results implied that the texture of the PZT films was sensitive to the pyrolysis conditions after spin-coating, but less dependent on the film's thickness. The texture had mainly a (111)-orientation for pyrolysis temperatures from 330 to 400 °C, and changes in the (100)- orientation occurred for pyrolysis temperatures at or above 450 °C after annealing at 650 °C for 5 min. The formation of a preferred texture could be explained by using the intermetallic phases and the internal stress energies between the substrate and the film. The ferroelectric properties of the PZT films fabricated by using this method have been found to be enhanced as compared to those of the PZT films fabricated by using the conventional spin-coating method and to be correlated to the microstructure of the film.

  2. Substrate heating effect on the growth of a CdTe film on an InSb substrate by vacuum evaporation

    NASA Astrophysics Data System (ADS)

    Jiann-Ruey, Chen; Mau-Phon, Houng; Fenq-Lin, Jenq; Chien-Shyong, Fang; Wan-Sun, Tse

    1991-07-01

    Epitaxial CdTe thin films were grown on the (111) oriented InSb substrate by vacuum evaporation, with the substrate kept at 190-225°C during the film deposition. The chamber pressure during film deposition was at 3.5 × 10-6 mbar. X-ray diffraction was used to determine the film structure, while the full width at half maximum (FWHM) of the X-ray diffraction peak was used to examine the crystallinity of the as-deposited films. The film morphology was observed by the scanning electron microscope (SEM), and the film composition was determined by electron probe microanalysis (EPMA). The film quality was examined by infrared transmission spectroscopy. Results indicate that the quality of the grown CdTe films was improved with the higher substrate temperature during the film deposition.

  3. High permittivity Bi24Fe2O39 thin films prepared by a low temperature process

    NASA Astrophysics Data System (ADS)

    Zhu, X. H.; Defaÿ, E.; Lee, Y.; André, B.; Aïd, M.; Zhu, J. L.; Xiao, D. Q.; Zhu, J. G.

    2010-12-01

    High permittivity Bi24Fe2O39 (BFO) thin films have been deposited on platinized silicon substrates by a low temperature process combining rf magnetron sputtering at room temperature and postdeposition annealing at 450 °C. A nearly pure tetragonal crystal structure with highly (201)-preferred orientation, determined by x-ray diffraction, was formed in the BFO thin film. The BFO film not only exhibits high dielectric permittivity (ɛr=113) and relatively low loss tangent (tan δ=0.012), but also shows a fairly small quadratic voltage coefficient of capacitance (α ˜800 ppm/V2) and a small temperature coefficient of capacitance (αT˜790 ppm/°C). Moreover, the leakage current density, obeying the Fowler-Nordheim tunneling mechanism, remains at a reasonably low level with the increase in applied electric field (J ˜10-6-10-4 A/cm2 under E=400 kV/cm). These attractive dielectric and electrical properties make the low temperature processed Bi24Fe2O39 thin film a promising candidate for high-k dielectric applications in silicon-based integrated circuits.

  4. Optical properties of epitaxial YAG:Yb films

    NASA Astrophysics Data System (ADS)

    Ubizskii, S. B.; Matkovskii, A. O.; Melnyk, S. S.; Syvorotka, I. M.; Müller, V.; Peters, V.; Petermann, K.; Beyertt, A.; Giesen, A.

    2004-03-01

    This work deals with the investigation of the optical properties of epitaxial YAG:Yb films and their suitability as gain media for thin disk lasers. Epitaxial films of YAG:Yb were grown by the liquid phase epitaxy method in air on the (111)-oriented YAG substrates. The thickness of the grown layers was from 30 to 260 m. The melt composition was varied to obtain the desired doping level from 10 to 15% and to optimize the optical properties. The best epitaxial films were colourless and had an Yb3+ luminescence lifetime of more than 950 s, which is very close to the intrinsic lifetime of the Yb ions in the bulk YAG single crystals. These films were tested in a thin disk laser setup with 24 absorption passes of the 940 nm pumping beam. The maximum output power at 1.03 m wavelength in CW operation reached more than 60 W and the optical efficiency was close to 30%.

  5. A pseudo-single-crystalline germanium film for flexible electronics

    SciTech Connect

    Higashi, H.; Yamada, S.; Kanashima, T.; Hamaya, K.; Kasahara, K.; Park, J.-H.; Miyao, M.; Kudo, K.; Okamoto, H.; Moto, K.; Tsunoda, I.

    2015-01-26

    We demonstrate large-area (∼600 μm), (111)-oriented, and high-crystallinity, i.e., pseudo-single-crystalline, germanium (Ge) films at 275 °C, where the temperature is lower than the softening temperature of a flexible substrate. A modulated gold-induced layer exchange crystallization method with an atomic-layer deposited Al{sub 2}O{sub 3} barrier and amorphous-Ge/Au multilayers is established. From the Raman measurements, we can judge that the crystallinity of the obtained Ge films is higher than those grown by aluminum-induced-crystallization methods. Even on a flexible substrate, the pseudo-single-crystalline Ge films for the circuit with thin-film transistor arrays can be achieved, leading to high-performance flexible electronics based on an inorganic-semiconductor channel.

  6. Fabrication of crystalline Ge thin films by co-deposition of Au and Ge at low substrate temperatures (<200 °C) without post annealing

    NASA Astrophysics Data System (ADS)

    Sugiyama, Takatoshi; Mishiba, Naoya; Kamiko, Masao; Kyuno, Kentaro

    2016-09-01

    Crystalline Ge thin films with (111) orientation are obtained by co-depositing Au and Ge on a substrate heated to ∼170 °C, with Au segregating at the film surface, which is desirable for selective etching. Although in the conventional metal-induced crystallization method using Au as a catalyst, a bilayer of Au and amorphous Ge layers have to be annealed for Ge to crystallize, the film in this study is already crystalline in the as-deposited state. The effective crystallization process implies the existence of a supercooled liquid alloy layer at the growth front.

  7. High piezoelectricity of Pb(Zr,Ti)O{sub 3}-based ternary compound thin films on silicon substrates

    SciTech Connect

    Zhang Tao; Zhang Shuyi; Chen Zhaojiang; Zhou Fengmei; Zhang Zhongning; Yang Yuetao; Wasa, Kiyotaka

    2009-03-23

    Pb(Zr,Ti)O{sub 3} (PZT)-based ternary compound thin films, 0.06PMnN-0.94PZT(50/50) (PMnN-PZT), are deposited on Si-based heterostructures by rf magnetron sputtering system. The intrinsic PZT(50/50) thin films are also deposited on the same kind of substrates for comparison. The PMnN-PZT thin films show the similar polycrystalline structures as those of PZT with highly (111) oriented perovskite phase. The PMnN-PZT thin films show excellent piezoelectricity and ferroelectricity which are distinctly better than those of PZT thin films prepared with the same deposition conditions. Besides, the cantilevers of PMnN-PZT thin films on the heterostructure substrates also exhibit higher sensitivities than the PZT thin film cantilevers.

  8. Monolayer graphene growth on sputtered thin film platinum

    SciTech Connect

    Kang, Byung Jin; Mun, Jeong Hun; Cho, Byung Jin; Hwang, Chan Yong

    2009-11-15

    It is demonstrated that sputtered thin film platinum (Pt) can be used as a catalytic metal for graphene growth on metal. During the crystallization annealing, the sputtered Pt is crystallized mostly into Pt (111) orientation, maintaining excellent surface roughness with no sign of agglomeration. The relatively lower carbon solubility in Pt and the good surface roughness of the thin film Pt enable us to form a uniform monolayer graphene on Pt over the entire region of the thin film Pt/SiO{sub 2}/Si substrate by carbon dissolution and segregation method processed in a methane ambient. The monolayer graphene grown on Pt has been successfully transferred to SiO{sub 2}/Si substrate by simple wet etching of Pt. The results of Raman spectroscopic and scanning tunneling microscopic measurements of the synthesized graphene layer are presented.

  9. Introduction of an artificial domain wall into BiFeO3 thin film using SrTiO3 bicrystal substrate

    NASA Astrophysics Data System (ADS)

    Fujisawa, Hironori; Seto, Shota; Nakashima, Seiji; Shimizu, Masaru

    2015-10-01

    For the future realization of nanoelectronic devices using domain walls (DWs) in ferroelectric thin films as a functional element, the artificial introduction and position control of DWs in BiFeO3 (BFO) thin films using SrTiO3 bicrystal substrates are demonstrated. The BFO thin film follows the bicrystal nature of SrTiO3, and consequently the boundary with an out-of-plane misorientation angle of 8° is formed immediately above that of the substrate. The boundary shows a charged nature induced by a head-to-head polarization configuration. The BFO bicrystal film exhibits a well-saturated polarization hysteresis loop equivalent to those of single-crystalline films. The piezoresponse scanning force microscopy of polarization switching suggests ferroelastic relaxation-mediated 180° switching through 71° switching. Although the boundary corresponds to a low-angle symmetry boundary with misfit dislocations, experimental results show that it behaves just like normal DWs by crystallographic twinning. Therefore, it is concluded that the artificially introduced boundary can be considered as a charged 101° DW.

  10. Highly oriented {delta}-Bi{sub 2}O{sub 3} thin films stable at room temperature synthesized by reactive magnetron sputtering

    SciTech Connect

    Lunca Popa, P.; Kerdsongpanya, S.; Lu, J.; Eklund, P.; Sonderby, S.; Bonanos, N.

    2013-01-28

    We report the synthesis by reactive magnetron sputtering and structural characterization of highly (111)-oriented thin films of {delta}-Bi{sub 2}O{sub 3}. This phase is obtained at a substrate temperature of 150-200 Degree-Sign C in a narrow window of O{sub 2}/Ar ratio in the sputtering gas (18%-20%). Transmission electron microscopy and x-ray diffraction reveal a polycrystalline columnar structure with (111) texture. The films are stable from room temperature up to 250 Degree-Sign C in vacuum and 350 Degree-Sign C in ambient air.

  11. Switchable diode-effect mechanism in ferroelectric BiFeO{sub 3} thin film capacitors

    SciTech Connect

    Matsuo, Hiroki; Kitanaka, Yuuki; Inoue, Ryotaro; Noguchi, Yuji Miyayama, Masaru

    2015-09-21

    We investigate the mechanism of a switchable diode behavior observed in ferroelectric SrRuO{sub 3}/BiFeO{sub 3} (BFO)/SrRuO{sub 3} capacitors. We experimentally demonstrate that the switchable diode effect observed in the capacitors is induced by the polarization reversal in the BFO film. The conductivity in an Ohmic region in different oxidation states provides direct evidence that electron hole acts as the majority carrier, delivering p-type conduction. Density functional theory (DFT) calculations show that the p-type conduction arises from an unoccupied gap state of Fe{sup 4+} in an FeO{sub 5} pyramid which is derived from Bi vacancy. Our experimental and DFT study leads to the conclusion that the switchable diode effect originates from an asymmetric band bending in the top and bottom depletion layers modulated by ferroelectric polarization and oxygen vacancies.

  12. Growth and characterization of thin oriented Co{sub 3}O{sub 4} (111) films obtained by decomposition of layered cobaltates Na{sub x}CoO{sub 2}

    SciTech Connect

    Buršík, Josef; Soroka, Miroslav; Kužel, Radomír; Mika, Filip

    2015-07-15

    The formation and structural characterization of highly (111)-oriented Co{sub 3}O{sub 4} films prepared by a novel procedure from weakly (001)-oriented Na{sub x}CoO{sub 2} is reported. The Na{sub x}CoO{sub 2} films were deposited on both single crystal and amorphous substrates by chemical solution deposition (CSD) method and crystallized at 700 °C. Subsequently they were transformed into (111)-oriented Co{sub 3}O{sub 4} phase during post-growth annealing at 900 °C. The degree of preferred orientation in Co{sub 3}O{sub 4}, which was determined by phi-scan and pole figure measurements, depends on the content of Na in the starting Na{sub x}CoO{sub 2} phase. Surface morphology of the films was investigated using electron microscopy and atomic force microscopy. - Graphical abstract: Structure of growth twins and possible O{sup 2−} stacking sequences in (111)-oriented Co{sub 3}O{sub 4} thin films on α-Al{sub 2}O{sub 3}(001) prepared by chemical solution deposition through the transformation of (001)-oriented Na{sub x}CoO{sub 2} thin film. - Highlights: • Single phase Co{sub 3}O{sub 4} thin films was prepared by means of chemical solution deposition. • Conditions for γ-Na{sub x}CoO{sub 2} to Co{sub 3}O{sub 4} transformation were optimized. • Growth twinning of Co{sub 3}O{sub 4} films due to two possible O{sup 2−} stacking sequences. • Growth with (pseudo)epitaxial relation Co{sub 3}O{sub 4} (111)[−121]//α-Al{sub 2}O{sub 3} (001)[10−10].

  13. Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films

    DOE PAGESBeta

    Gallagher, J. C.; Esser, B. D.; Morrow, R.; Dunsiger, S. R.; Williams, R. E. A.; Woodward, P. M.; McComb, D. W.; Yang, F. Y.

    2016-02-29

    Epitaxial films of the pyrochlore Nd2Ir2O7 have been grown on (111)-oriented yttria-stabilized zirconia (YSZ) substrates by off-axis sputtering followed by post-growth annealing. X-ray diffraction (XRD) results demonstrate phase-pure epitaxial growth of the pyrochlore films on YSZ. Scanning transmission electron microscopy (STEM) investigation of an Nd2Ir2O7 film with a short post-annealing provides insight into the mechanism for crystallization of Nd2Ir2O7 during the post-annealing process. STEM images reveal clear pyrochlore ordering of Nd and Ir in the films. As a result, the epitaxial relationship between the YSZ and Nd2Ir2O7 is observed clearly while some interfacial regions show a thin region with polycrystallinemore » Ir nanocrystals.« less

  14. Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films

    PubMed Central

    Gallagher, J. C.; Esser, B. D.; Morrow, R.; Dunsiger, S. R.; Williams, R. E. A.; Woodward, P. M.; McComb, D. W.; Yang, F. Y.

    2016-01-01

    Epitaxial films of the pyrochlore Nd2Ir2O7 have been grown on (111)-oriented yttria-stabilized zirconia (YSZ) substrates by off-axis sputtering followed by post-growth annealing. X-ray diffraction (XRD) results demonstrate phase-pure epitaxial growth of the pyrochlore films on YSZ. Scanning transmission electron microscopy (STEM) investigation of an Nd2Ir2O7 film with a short post-annealing provides insight into the mechanism for crystallization of Nd2Ir2O7 during the post-annealing process. STEM images reveal clear pyrochlore ordering of Nd and Ir in the films. The epitaxial relationship between the YSZ and Nd2Ir2O7 is observed clearly while some interfacial regions show a thin region with polycrystalline Ir nanocrystals. PMID:26923862

  15. Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films

    NASA Astrophysics Data System (ADS)

    Gallagher, J. C.; Esser, B. D.; Morrow, R.; Dunsiger, S. R.; Williams, R. E. A.; Woodward, P. M.; McComb, D. W.; Yang, F. Y.

    2016-02-01

    Epitaxial films of the pyrochlore Nd2Ir2O7 have been grown on (111)-oriented yttria-stabilized zirconia (YSZ) substrates by off-axis sputtering followed by post-growth annealing. X-ray diffraction (XRD) results demonstrate phase-pure epitaxial growth of the pyrochlore films on YSZ. Scanning transmission electron microscopy (STEM) investigation of an Nd2Ir2O7 film with a short post-annealing provides insight into the mechanism for crystallization of Nd2Ir2O7 during the post-annealing process. STEM images reveal clear pyrochlore ordering of Nd and Ir in the films. The epitaxial relationship between the YSZ and Nd2Ir2O7 is observed clearly while some interfacial regions show a thin region with polycrystalline Ir nanocrystals.

  16. Insight into magnetic, ferroelectric and elastic properties of strained BiFeO3 thin films through Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Agbelele, A.; Sando, D.; Infante, I. C.; Carrétéro, C.; Jouen, S.; Le Breton, J.-M.; Barthélémy, A.; Dkhil, B.; Bibes, M.; Juraszek, J.

    2016-07-01

    We have studied the magnetic order of highly strained (001)-oriented BiFeO3 (BFO) thin films using 57Fe Conversion Electron Mössbauer Spectrometry. From 90 K to 620 K the films exhibit a collinear antiferromagnetic structure, in contrast with the cycloidal structure observed in bulk BFO. Moreover, we find that both the planar magnetic anisotropy for compressive strain and out-of-plane anisotropy for tensile strain persist from 90 K up to the Néel temperature (TN), which itself shows only a weak strain dependence. An analysis of the line asymmetry of the paramagnetic doublet for temperatures above TN is used to reveal the strain-dependent rotation of the polarization direction, consistent with previous observations. Our results show that the lattice dynamics in BFO films are strongly strain-dependent, offering avenues toward acoustic phonon devices. Finally, we use the versatility of Mössbauer spectroscopy technique to reveal various multi-property features including magnetic states, polarization direction and elastic strain.

  17. Modulating the ratio of tetragonal/rhombohedral phases in strained BiFeO3 films by varying the oxygen pressure during deposition

    NASA Astrophysics Data System (ADS)

    Staruch, Margo; Kim, Heungsoo

    2014-03-01

    Room-temperature multiferroic BiFeO3 (BFO) has been the subject of recent research interest due to its potential applications in random access memory and other spintronic devices. Compressive strain in the BFO lattice results in a symmetry change from a rhombohedral to a monoclinically-distorted tetragonal structure, with intermediate strains lying near a morphotropic phase boundary. This has been demonstrated to lead to enhanced piezoelectric and dielectric properties. However, the effect of growth conditions, such as substrate temperature and oxygen partial pressure during deposition, on the multiferroic properties of strained BFO films has yet to be systematically studied. In this work, BiFeO3 thin films were grown on (001) LaAlO3 single crystal substrates by pulsed laser deposition at different oxygen partial pressures. By examining the structure and microstructure of the resulting films, the ratio of the tetragonal-like and rhombohedral phases was found to vary with oxygen deposition pressure. The effects of this modulation on the magnetic and ferroelectric properties will be presented. This work was funded by the Office of Naval Research (ONR) through the Naval Research Laboratory Basic Research Program.

  18. Bismuth ferrite based thin films, nanofibers, and field effect transistor devices

    NASA Astrophysics Data System (ADS)

    Rivera-Beltran, Rut

    In this research an attempt has been made to explore bismuth ferrite thin films with low leakage current and nanofibers with high photoconductivity. Thin films were deposited with pulsed laser deposition (PLD) method. An attempt has been made to develop thin films under different deposition parameters with following target compositions: i) 0.6BiFeO3-0.4(Bi0.5 K0.5)TiO3 (BFO-BKT) and ii) bi-layered 0.88Bi 0.5Na0.5TiO3-0.08Bi0.5K0.5TiO 3-0.04BaTiO3/BiFeO3 (BNT-BKT-BT/BFO). BFO-BKT thin film shows suppressed leakage current by about four orders of magnitude which in turn improve the ferroelectric and dielectric properties of the films. The optimum remnant polarization is 19 muC.cm-2 at the oxygen partial pressure of 300 mtorr. The BNT-BKT-BT/BFO bi-layered thin films exhibited ferroelectric behavior as: Pr = 22.0 muC.cm-2, Ec = 100 kV.cm-1 and epsilonr = 140. The leakage current of bi-layered thin films have been reduced two orders of magnitude compare to un-doped bismuth ferrite. Bismuth ferrite nanofibers were developed by electrospinning technique and its electronic properties such as photoconductivity and field effect transistor performance were investigated extensively. Nanofibers were deposited by electrospinning of sol-gel solution on SiO2/Si substrate at driving voltage of 10 kV followed by heat treatment at 550 °C for 2 hours. The composition analysis through energy dispersive detector and electron energy loss spectroscopy revealed the heterogeneous nature of the composition with Bi rich and Fe deficient regions. X-ray photoelectron spectroscopy results confirmed the combination of Fe3+ and Fe2+ valence state in the fibers. The photoresponse result is almost hundred times higher for a fiber of 40 nm diameter compared to a fiber with 100 nm diameter. This effect is described by a size dependent surface recombination mechanism. A single and multiple BFO nanofibers field effect transistors devices were fabricated and characterized. Bismuth ferrite FET behaves

  19. Magnetic Properties of Polycrystalline Bismuth Ferrite Thin Films Grown by Atomic Layer Deposition.

    PubMed

    Jalkanen, Pasi; Tuboltsev, Vladimir; Marchand, Benoît; Savin, Alexander; Puttaswamy, Manjunath; Vehkamäki, Marko; Mizohata, Kenichiro; Kemell, Marianna; Hatanpää, Timo; Rogozin, Valentin; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku

    2014-12-18

    The atomic layer deposition (ALD) method was applied to grow thin polycrystalline BiFeO3 (BFO) films on Pt/SiO2/Si substrates. The 50 nm thick films were found to exhibit high resistivity, good morphological integrity, and homogeneity achieved by the applied ALD technique. Magnetic characterization revealed saturated magnetization of 25 emu/cm(3) with temperature-dependent coercivity varying from 5 to 530 Oe within the temperature range from 300 to 2 K. Magnetism observed in the films was found to change gradually from ferromagnetic spin ordering to pinned magnetic domain interactions mixed with weak spin-glass-like behavior of magnetically frustrated antiferromagnetic/ferromagnetic (AFM-FM) spin ordering depending on the temperature and magnitude of the applied magnetic field. Antiferromagnetic order of spin cycloids was broken in polycrystalline films by crystal sizes smaller than the cycloid length (∼60 nm). Uncompensated spincycloids and magnetic domain walls were found to be the cause of the high magnetization of the BFO films. PMID:26273981

  20. Growth of epitaxial films of iron oxide, nickel oxide, cobalt oxide, strontium hexagonal ferrite, and yttrium iron garnet by laser ablation (abstract)

    SciTech Connect

    Kennedy, R.J.

    1996-04-01

    Thin films of iron oxide, nickel oxide, cobalt oxide, strontium hexagonal ferrite, and yttrium iron garnet have been grown by laser ablation. With the exception of Co{sub 3}O{sub 4} deposited on LaAlO{sub 3}, the first three materials deposited on [100] LaAlO{sub 3}, SrTiO{sub 3}, and MgO result in high quality {ital c} axis [100] growth. Co{sub 3}O{sub 4} deposited on LaAlO{sub 3} produces highly oriented but random in-plane growth. Similar highly oriented but random in-plane growth occurs for all three materials deposited on glass. The same three materials deposited on cubic zirconia grow [111] oriented and twinned. Strontium hexagonal ferrite and yttrium iron garnet have been deposited on [111] large lattice constant garnet. Epitaxial [0001] films are obtained for the former while the latter gives [111]-oriented films. For yttrium iron garnet the closeness of lattice match to the substrate necessitates that the mosaicity (rocking curves) obtained from area maps be compared to the growth temperatures and pressures to determine the optimum growth conditions for epitaxiality. {copyright} {ital 1996 American Institute of Physics.}

  1. Strain evolution of each type of grains in poly-crystalline (Ba,Sr)TiO3 thin films grown by sputtering

    NASA Astrophysics Data System (ADS)

    Park, Woo Young; Park, Min Hyuk; Lee, Jong Ho; Yoon, Jung Ho; Han, Jeong Hwan; Choi, Jung-Hae; Hwang, Cheol Seong

    2012-12-01

    The strain states of [111]-, [110]-, and [002]-oriented grains in poly-crystalline sputtered (Ba,Sr)TiO3 thin films on highly [111]-oriented Pt electrode/Si substrates were carefully examined by X-ray diffraction techniques. Remarkably, [002]-oriented grains respond more while [110]- and [111]-oriented grains do less than the theoretically estimated responses, which is understandable from the arrangement of the TiO6 octahedra with respect to the stress direction. Furthermore, such mechanical responses are completely independent of the degree of crystallization and film thickness. The transition growth temperature between the positive and negative strains was also different depending on the grain orientation. The unstrained lattice parameter for each type of grain was different suggesting that the oxygen vacancy concentration for each type of grain is different, too. The results reveal that polycrystalline (Ba,Sr)TiO3 thin films are not an aggregation of differently oriented grains which simply follow the mechanical behavior of single crystal with different orientations.

  2. Effects of substrate annealing and post-crystallization thermal treatments on the functional properties of preferentially oriented (Pb,Ca)TiO3 thin films

    NASA Astrophysics Data System (ADS)

    Poyato, R.; Calzada, M. L.; Pardo, L.

    2003-04-01

    <111> and <001>,<100> preferentially oriented calcium-modified lead titanate thin films have been studied. Effects of the substrate annealing and post-crystallization thermal treatment of the films on the texture and ferro-, piezo-, and pyroelectric properties have been analyzed and discussed. The annealing of the substrate has effect on the texture of <001>,<100>-oriented films and, as a consequence, produces an increase in the net polarization in the perpendicular direction to the plane of the film and in the pyroelectric coefficient. The annealing of the substrate does not affect the texture of <111>-oriented films, but the electrical properties at the electrode-substrate interface and, as a consequence, gives place to high internal electric fields leading to the highest spontaneous piezo- (5 pm V-1) and pyroelectric coefficients (25.0×10-9 C cm-2 K-1). The asymmetry that characterizes the functional properties of <111>-oriented films under poling with negative or positive polarity is also consequence of such a high internal field. This is accompanied with a remarkable field stability of the piezoelectric d33 coefficient when poling in the sense of the spontaneous polarization (d33˜45 pm V-1 under ±200 kV cm-1). The application of post-crystallization thermal treatment results in an enhancement of the ferroelectric and pyroelectric properties in all the films, by liberation of domains that were clamped by charged defects. Both the substrate and post-crystallization film annealing treatments lead to reach the highest values of remanent polarization (43 μC cm-2), pyroelectric coefficient (42.0×10-9 C cm-2 K-1), and figure of merit [13.3×10-6 (N m-2)-1/2] reported to date for sol-gel PTC films.

  3. Emergence of magnetic order in ultra-thin pyrochlore iridate films

    NASA Astrophysics Data System (ADS)

    Cheema, Suraj; Serrao, Claudy; Mundy, Julia; Patankar, Shreyas; Birgeneau, Robert; Orenstein, Joseph; Salahuddin, Sayeef; Ramesh, Ramamoorthy

    We report on thickness-dependent magnetotransport in (111) - oriented Pb2Ir2O7-x (Pb227) epitaxial thin films. For thicknesses greater than 4 nm, the magnetoresistance (MR) of metallic Pb227 is positive, linear and non-saturated up to 14 T. Meanwhile at 4 nm, the conduction turns nonmetallic and the MR becomes negative and asymmetric upon field-cooling; such traits are reminiscent of all-in-all-out (AIAO) magnetic order in the insulating pyrochlore iridates. Hysteretic low-field MR dips and trained-untrained resistivity bifurcations suggest the presence of magnetic conducting domain walls within the chiral AIAO spin structure. Beyond just AIAO order, angular-dependent MR indicates a magnetic phase space hosting 2-in-2-out (2I2O) spin ice order. Such anomalous magnetotransport calls for re-evaluation of the pyrochlore iridate phase diagram, as epitaxially strained Pb227 exhibits traits reminiscent of both the insulating magnetic and metallic spin-liquid members. Furthermore, these results open avenues for realizing topological phase predictions in (111) - oriented pyrochlore slabs of kagome-triangular iridate heterostructures. This work is supported by the Office of Basic Energy Sciences of the US Department of Energy under Contract No. DE-AC02-05CH11231.

  4. Unconventional magnetization of Fe3O4 thin film grown on amorphous SiO2 substrate

    NASA Astrophysics Data System (ADS)

    Yin, Jia-Xin; Liu, Zhi-Guo; Wu, Shang-Fei; Wang, Wen-Hong; Kong, Wan-Dong; Richard, Pierre; Yan, Lei; Ding, Hong

    2016-06-01

    High quality single crystal Fe3O4 thin films with (111) orientation had been prepared on amorphous SiO2 substrate by pulsed laser deposition. The magnetization properties of the films are found to be unconventional. The Verwey transition temperature derived from the magnetization jump is around 140K, which is higher than the bulk value and it can be slightly suppressed by out-plane magnetic field; the out-of-plane magnetization, which is unexpectedly higher than the in-plane value, is also significantly increased as compared with the bulk value. Our findings highlight the unusual magnetization of Fe3O4 thin film grown on the amorphous SiO2 substrate.

  5. Nanoparticle-Sintered BaTiO3 Thin Films and Its Orientation Control by Solid Phase Epitaxy

    NASA Astrophysics Data System (ADS)

    Nakasone, Fumi; Kobayashi, Keisuke; Suzuki, Toshimasa; Mizuno, Youichi; Chazono, Hirokazu; Imai, Hiroaki

    2008-11-01

    A novel powder-sintering thin-film process using nanocrystals of sol-gel-derived BaTiO3 without sintering additives yields a highly densified microstructure containing columnar grains at low temperatures of 800 °C. The BaTiO3 thin film fabricated on a (111)-oriented Pt/TiO2/Al2O3 substrate shows high crystallinity and a relatively high dielectric constant of 635 at 10 kHz with a low loss tangent of 0.007. Furthermore, the controllability of the crystallographic orientations of thin films by solid phase epitaxy is demonstrated on the basis of the optimization of surface nucleation and the subsequent grain growth on epitaxially grown platinum electrodes and single-crystal SrTiO3 substrates.

  6. Chemical solution deposition derived (001)-oriented epitaxial BiFeO{sub 3} thin films with robust ferroelectric properties using stoichiometric precursors (invited)

    SciTech Connect

    Zhang, Qi; Valanoor, Nagarajan; Standard, Owen

    2014-08-14

    Phase pure bismuth ferrite (BiFeO{sub 3}) thin films with (001)-oriented epitaxial structure are realized on lanthanum strontium manganite (La{sub 0.67}Sr{sub 0.33}MnO{sub 3}) buffered (001)-SrTiO{sub 3} substrates by chemical solution deposition. The annealing process is optimized such that a stoichiometric precursor can be used to accurately control the Bi:Fe ratio. Ferroelectric, dielectric, and resistive switching behaviours are investigated for 40 nm, 70 nm, and 150 nm BFO thin films. While the thinnest film (40 nm) shows very leaky loops, square and fully saturated polarization hysteresis loops are shown for the thicker films. The highest remanent polarization (2P{sub r} = 100 μC/cm{sup 2}) and relative dielectric constant (ε{sub r} = 613) are obtained in the 150 nm BFO thin film. High cycle fatigue tests show that the thick films are resistant to polarization fatigue. Piezoresponse force microscopy results show that the domain structure varies with thickness. Resistive switching and polarization mediated diode effects are also observed. These robust properties suggest that chemical solution deposition derived BiFeO{sub 3} thin films can offer a viable low cost alternative.

  7. Chemical solution deposition derived (001)-oriented epitaxial BiFeO3 thin films with robust ferroelectric properties using stoichiometric precursors (invited)

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Valanoor, Nagarajan; Standard, Owen

    2014-08-01

    Phase pure bismuth ferrite (BiFeO3) thin films with (001)-oriented epitaxial structure are realized on lanthanum strontium manganite (La0.67Sr0.33MnO3) buffered (001)-SrTiO3 substrates by chemical solution deposition. The annealing process is optimized such that a stoichiometric precursor can be used to accurately control the Bi:Fe ratio. Ferroelectric, dielectric, and resistive switching behaviours are investigated for 40 nm, 70 nm, and 150 nm BFO thin films. While the thinnest film (40 nm) shows very leaky loops, square and fully saturated polarization hysteresis loops are shown for the thicker films. The highest remanent polarization (2Pr = 100 μC/cm2) and relative dielectric constant (ɛr = 613) are obtained in the 150 nm BFO thin film. High cycle fatigue tests show that the thick films are resistant to polarization fatigue. Piezoresponse force microscopy results show that the domain structure varies with thickness. Resistive switching and polarization mediated diode effects are also observed. These robust properties suggest that chemical solution deposition derived BiFeO3 thin films can offer a viable low cost alternative.

  8. Co-sputtering NbTiN thin films on PSG/Si substrates

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Zhang, Jingjiao; Zhang, Lu; You, Lixing; Su, Xiaodong

    2016-02-01

    Single-crystalline silicon is one of a few promising substrate materials on which to grow NbTiN ultrathin films for applications in superconducting single photon detection devices. In this work, a buffer layer of phosphorus silicate glass (PSG) ∼250 nm is formed rapidly on the silicon substrate under a relatively low temperature to ease the mismatching between NbTiN and substrate, and simultaneously act as an antireflection layer at the working wavelength. (111)-oriented NbTiN films were deposited on both SiO2/Si and PSG/Si substrates by using a dc reactive magnetron co-sputtering system of independent Nb and Ti targets. The superconducting critical temperature T c of the 5 nm-NbTiN/PSG/Si sample reaches ∼8.8 K due to effectively relieving the mismatch between NbTiN and Si by PSG buffer layer.

  9. Growth of CdTe films on GaAs by ionized cluster beam epitaxy

    NASA Astrophysics Data System (ADS)

    Tang, H. P.; Feng, J. Y.; Fan, Y. D.; Li, H. D.

    1991-06-01

    Stoichiometric epitaxial films of CdTe were grown on (100)GaAs substrates by ionized cluster beam (ICB) epitaxy. Streaky RHEED patterns indicated good crystallinity and surface flatness of the epitaxial CdTe films. CdTe(100) orientation was obtained when the substrate preheating temperature was 480°C, while CdTe growth inboth (100) and (111) orientations occured when the substrate preheating temperature was above 550°C. The characteristics of the ICB growth process were investigated and the cluster-involving growth behavior has been evidenced. When sufficient clusters were generated in the deposition beam under adequate source vapor pressures, the crystalline quality of the resulting CdTe epilayers improved significantly with the increase of kinetic energy of the CdTe clusters. The best CdTe epilayer obtained exhibited a CdTe(400) double crystal rocking curve (DCRC) having a FWHM of 630 arc sec.

  10. Structural evolution of platinum thin films grown by atomic layer deposition

    SciTech Connect

    Geyer, Scott M.; Methaapanon, Rungthiwa; Bent, Stacey; Johnson, Richard; Clemens, Bruce; Brennan, Sean; Toney, Mike F.

    2014-08-14

    The structural properties of Pt films grown by atomic layer deposition (ALD) are investigated with synchrotron based x-ray scattering and x-ray diffraction techniques. Using grazing incidence small angle scattering, we measure the lateral growth rate of the Pt islands to be 1.0 Å/cycle. High resolution x-ray diffraction reveals that the in-plane strain of the Pt lattice undergoes a transition from compressive strain to tensile strain when the individual islands coalescence into a continuous film. This transition to tensile strain is attributed to the lateral expansion that occurs when neighboring islands merge to reduce their surface energy. Using 2D grazing incidence x-ray diffraction, we show that the lattice orientation becomes more (111) oriented during deposition, with a sharp transition occurring during coalescence. Pt ALD performed at a lower deposition temperature (250 °C) is shown to result in significantly more randomly oriented grains.

  11. Comparison of CDMS [100] and [111] Oriented Germanium Detectors

    SciTech Connect

    Leman, S.W.; Hertel, S.A.; Kim, P.; Cabrera, B.; Do Couto E.Silva, E.; Figueroa-Feliciano, E.; McCarthy, K.A.; Resch, R.; Sadoulet, B.; Sundqvist, K.M.; /UC, Berkeley

    2012-09-14

    The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3-inch diameter x 1-inch thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors and comparison of energy in each channel provides event-by-event classification of electron and nuclear recoils. Fiducial volume is determined by the ability to obtain good phonon and ionization signal at a particular location. Due to electronic band structure in germanium, electron mass is described by an anisotropic tensor with heavy mass aligned along the symmetry axis defined by the [111] Miller index (L valley), resulting in large lateral component to the transport. The spatial distribution of electrons varies significantly for detectors which have their longitudinal axis orientations described by either the [100] or [111] Miller indices. Electric fields with large fringing component at high detector radius also affect the spatial distribution of electrons and holes. Both effects are studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is discussed.

  12. Pulsed laser deposition of niobium nitride thin films

    SciTech Connect

    Farha, Ashraf Hassan Elsayed-Ali, Hani E.; Ufuktepe, Yüksel; Myneni, Ganapati

    2015-12-04

    Niobium nitride (NbN{sub x}) films were grown on Nb and Si(100) substrates using pulsed laser deposition. NbN{sub x} films were deposited on Nb substrates using PLD with a Q-switched Nd:YAG laser (λ = 1064 nm, ∼40 ns pulse width, and 10 Hz repetition rate) at different laser fluences, nitrogen background pressures and deposition substrate temperatures. When all the fabrication parameters are fixed, except for the laser fluence, the surface roughness, nitrogen content, and grain size increase with increasing laser fluence. Increasing nitrogen background pressure leads to a change in the phase structure of the NbN{sub x} films from mixed β-Nb{sub 2}N and cubic δ-NbN phases to single hexagonal β-Nb{sub 2}N. The substrate temperature affects the preferred orientation of the crystal structure. The structural and electronic, properties of NbN{sub x} deposited on Si(100) were also investigated. The NbN{sub x} films exhibited a cubic δ-NbN with a strong (111) orientation. A correlation between surface morphology, electronic, and superconducting properties was found. The observations establish guidelines for adjusting the deposition parameters to achieve the desired NbN{sub x} film morphology and phase.

  13. Photovoltaic effect in transition metal modified polycrystalline BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Sreenivas Puli, Venkata; Pradhan, Dhiren Kumar; Katiyar, Rajesh Kumar; Coondoo, Indrani; Panwar, Neeraj; Misra, Pankaj; Chrisey, Douglas B.; Scott, J. F.; Katiyar, Ram S.

    2014-02-01

    We report photovoltaic (PV) effect in multiferroic Bi0.9Sm0.1Fe0.95Co0.05O3 (BSFCO) thin films. Transition metal modified polycrystalline BiFeO3 (BFO) thin films have been deposited on Pt/TiO2/SiO2/Si substrate successfully through pulsed laser deposition (PLD). PV response is observed under illumination both in sandwich and lateral electrode configurations. The open-circuit voltage (Voc) and the short-circuit current density (Jsc) of the films in sandwich electrode configuration under illumination are measured to be 0.9 V and -0.051 µA cm-2. Additionally, we report piezoresponse for BSFCO films, which confirms ferroelectric piezoelectric behaviour.

  14. Mössbauer spectra and electric properties of 57Fe-enriched BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Tanaka, Kiyotaka; Fujita, Yuya; Okamura, Soichiro; Yoshida, Yutaka

    2014-09-01

    57Fe-enriched BiFeO3 (BFO) thin films are fabricated on Pt/Ti/SiO2/Si substrates from a stoichiometric precursor solution by chemical solution deposition process. The microstructure of the thin films is controlled by a changing the sintering time at 550 °C. The polycrystalline thin film fabricated at 550 °C for 5 min shows well-saturated polarization-electric field (P-E) hysteresis loops and the remnant polarization Pr and coercive field Ec at room temperature are 52 µC/cm2 and 365 kV/cm, respectively, at an applied electric field of 1200 kV/cm. The Mössbauer spectra show that the BFO thin film has the valence state of Fe3+ only, consisting of antiferromagnetic and paramagnetic components. The paramagnetic component with an area fraction from 11 to 18%, which is not amorphous or Bi2Fe4O9, seems to distribute in the surface shell of the grains and the grain boundaries. This component must strongly influence the ferroelectric properties at room temperature.

  15. High-rate growth of InN films on fianite and sapphire substrates by metalorganic vapor phase epitaxy with plasma-assisted nitrogen activation

    NASA Astrophysics Data System (ADS)

    Buzynin, Yu. N.; Vodop'yanov, A. V.; Golubev, S. V.; Drozdov, M. N.; Drozdov, Yu. N.; Luk'yanov, A. Yu.; Mansfeld, D. A.; Khrykin, O. I.; Shashkin, V. I.; Yunin, P. A.

    2015-03-01

    Hexagonal single-crystalline indium nitride (InN) films on (0001)-oriented sapphire (Al2O3) and (111)-oriented fianite (yttria-stabilized zirconia, YSZ) substrates and on (0001)-oriented GaN/Al2O3 templates have been grown at a record high rate of 10 μm/h by the method of metalorganic vapor phase epitaxy with nitrogen activation in plasma of electron cyclotron resonance discharge generated by gyrotron radiation. It is established that the use of fianite substrates significantly improves the structural perfection and photoluminescent properties of InN films as compared to those grown on sapphire and templates. Undoped InN films exhibit n-type conductivity with electron concentrations within n = 8.0 × 1019-4.9 × 1020 cm-3 and room-temperature mobilities up to 180 cm2/(V s).

  16. Unraveling the magnetic properties of BiFe0.5Cr0.5O3 thin films

    NASA Astrophysics Data System (ADS)

    Vinai, G.; Khare, A.; Rana, D. S.; Di Gennaro, E.; Gobaut, B.; Moroni, R.; Petrov, A. Yu.; Scotti di Uccio, U.; Rossi, G.; Miletto Granozio, F.; Panaccione, G.; Torelli, P.

    2015-11-01

    We investigate the structural, chemical, and magnetic properties on BiFe0.5Cr0.5O3 (BFCO) thin films grown on (001) (110) and (111) oriented SrTiO3 (STO) substrates by x-ray magnetic circular dichroism and x-ray diffraction. We show how highly pure BFCO films, differently from the theoretically expected ferrimagnetic behavior, present a very weak dichroic signal at Cr and Fe edges, with both moments aligned with the external field. Chemically sensitive hysteresis loops show no hysteretic behavior and no saturation up to 6.8 T. The linear responses are induced by the tilting of the Cr and Fe moments along the applied magnetic field.

  17. (001) and (111) Single-Oriented Highly Epitaxial CeO2 Thin Films on r-Cut Sapphire Substrates

    NASA Astrophysics Data System (ADS)

    Bick, D. S.; Sharath, S. U.; Hoffman, I.; Major, M.; Kurian, J.; Alff, L.

    2015-08-01

    We have studied the growth of CeO2 thin films by molecular beam epitaxy on r-cut sapphire substrates. The oxidation state of the substrate surface controls the growth direction of CeO2. Oxygen pre-annealed substrates favor (001) growth, while oxygen vacancies lead to a mixed (001) and (111) orientation. Combining pre- and post-annealing, it is possible to achieve single- oriented CeO2 in both growth directions. Furthermore, post-annealing results in a dramatic increase of crystallinity with a rocking curve width of the (002) reflection as small as 0.004°. We provide a consistent growth model involving oxygen vacancies at the substrate to thin film interface.

  18. Enhanced electrical properties of rare-earth-substituted (Bi0.9RE0.1)(Fe0.975Cr0.025)O3 (RE = Nd, Gd, Eu) thin films

    NASA Astrophysics Data System (ADS)

    Kim, Jin Won; Do, Dalhyun; Kim, Sang Su; Song, Tae Kwon; Kim, Myung Ho

    2012-11-01

    BiFeO3 and (Bi0.9 RE 0.1)(Fe0.975Cr0.025)O3 ( RE = Nd, Gd and Eu, BNFCr, BGFCr, and BEFCr, respectively) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. All the thin films were annealed at 550 °C for 30 min under a nitrogen atmosphere for crystallization. Compared to the pure BFO, the co-doped thin films exhibited good electrical properties, such as improved leakage current density and P- E hysteresis characteristics. The leakage current densities of the BFO, BNFCr, BGFCr, and BEFCr thin films were 2.58 × 10-3 A/cm2, 6.76 × 10-6 A/cm2, 5.14 × 10-6 A/cm2, and 9.60 × 10-5 A/cm2 at an electric field of 100 kV/cm, respectively. The remnant polarization (2 P r ) and the coercive electric field (2 E c ) values of the BFO, BGFNi, BGFCo, and BGFCr thin film were 35.2 µC/cm2 and 1376 kV/cm, 101.9 µC/cm2 and 1131 kV/cm, 81.2 µC/cm2 and 962 kV/cm, 67.1 µC/cm2 and 938 kV/cm, respectively, at an applied electric field of 1066 kV/cm. The improved leakage current and ferroelectric properties of the co-doped thin films are related to the change in the microstructure and the decrease in the number of oxygen vacancies.

  19. Growth, microstructure and supercapacitive performance of copper oxide thin films prepared by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Purusottam Reddy, B.; Sivajee Ganesh, K.; Hussain, O. M.

    2016-02-01

    The supercapacitive performance of copper oxide thin film electrodes mainly relies on micro structure, phase, surface area and conductivity which in turn depend on the deposition technique and process parameters during growth. In the present study, thin films of copper oxide were prepared by RF magnetron sputtering on stainless steel substrates keeping O2-to-Ar ratio at 1:11 and RF power at 250 W and varying the substrate temperature. The microstructure and the induced phase changes in copper oxide films are observed to be strongly influenced by the substrate temperature since the relaxation time, surface diffusion and surface structural changes are thermally activated. The XRD and Raman studies reveal that the films deposited at low substrate temperature (<200 °C) exhibited CuO, while the films deposited at substrate temperature >200 °C exhibited Cu2O phase. The films prepared at 350 °C exhibited reflections correspond to cubic Cu2O with predominant (111) orientation. The estimated maximum grain size from AFM studies was 72 nm with surface roughness of 51 nm. These films exhibited a highest areal capacitance of 30 mF cm-2 at scan rate of 5 mV s-1. The galvanostatic charge-discharge studies demonstrated high specific capacitance of 908 F g-1 at 0.5 mA cm-2 current density with 80 % of its initial capacity retention even after 1000 cycles.

  20. Surfactant assisted growth of MgO films on GaN

    SciTech Connect

    Paisley, E. A.; Shelton, T. C.; Collazo, R.; Sitar, Z.; Maria, J.-P.; Christen, H. M.; Biegalski, M. D.; Mita, S.

    2012-08-27

    Thin epitaxial films of <111> oriented MgO on [0001]-oriented GaN were grown by molecular beam epitaxy and pulsed laser deposition using the assistance of a vapor phase surfactant. In both cases, surfactant incorporation enabled layer-by-layer growth and a smooth terminal surface by stabilizing the {l_brace}111{r_brace} rocksalt facet. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly 100 Multiplication-Sign reduction in leakage current density for the surfactant-assisted samples. These data verify numerous predictions regarding the role of H-termination in regulating the habit of rocksalt crystals.

  1. Inducing phase transitions of T-like BiFeO3 films by low-energy He implantation

    NASA Astrophysics Data System (ADS)

    Herklotz, Andreas; Beekman, Christianne; Rus, Stefania Florina; Ivanov, Ilia; Balke, Nina; Ward, Thomas Zac

    Ferroelectric phase transitions of BiFeO3 are found to be controllable through the application of single axis, out-of-plane strain. Low-energy He implantation has been deployed to induce out-of-plane strain in T-like BFO films, while the compressive in-plane strain due to the coherent growth on LaAlO3 substrates remains fixed. Our data shows that He implantation triggers a MC -MA - T phase sequence of the T polymorph that is identical to structural changes that are induced with increasing temperature. Mixed phases nanodomains phases are gradually suppressed and disappear above a certain He doping level. Our data shows that the ferroelectric and optical properties of BiFeO3 films critically depend on the He doping level. Thus, the results demonstrates that He implantation can be used as an intriguing approach to study lines in the rich phase space of BFO films that can't be accessed by simple heteroepitaxy. This effort was wholly supported by the US Department of Energy (DOE), Office of Basic Energy Sciences (BES), Materials Sciences and Engineering Division, with user projects supported at ORNL's Center for Nanophase Materials Research (CNMS) which is also sponsored by DOE-BES.

  2. MOCVD of multimetal and noble metal films

    NASA Astrophysics Data System (ADS)

    Endle, James Patrick

    2000-11-01

    times were significantly increased, and step coverage and roughness were improved. The iridium crystal orientation was nearly random on the SiO2 substrate and strongly (111) oriented on the TiN(111) substrate. Conformal films (step coverage ≈ 1) were produced at 550 K on both substrates.

  3. Photo-carrier control of exchange bias in BiFeO{sub 3}/La{sub 2/3}Sr{sub 1/3}MnO{sub 3} thin films

    SciTech Connect

    Sung, K. D.; Lee, T. K.; Park, Y. A.; Hur, N.; Jung, J. H.

    2014-06-23

    We report the facile control of exchange bias in BiFeO{sub 3}/La{sub 2/3}Sr{sub 1/3}MnO{sub 3} (BFO/LSMO) thin films on an SrTiO{sub 3} (STO) substrate using light irradiation. Illumination with weak red light (λ: 630 nm, intensity: ∼1 mW/cm{sup 2}) reduced the exchange bias field (H{sub E}) of BFO/LSMO from +30 Oe in the dark to −2 Oe with red light. In accompanying the decrease of H{sub E}, the resistance of BFO/LSMO significantly increased. These results were attributed to the reduction in the hole-doping ratio of LSMO and the weakened exchange coupling between Fe and Mn spins at the interface, resulting from photo-injected electrons from the STO substrate. Successive turning on/off of red light gives rise to cyclical change of corresponding H{sub E}, which should be useful for applications like photo-controlled tunneling magnetoresistance devices.

  4. Oriented PrBaCo2O5+δ thin films for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Chen, Dengjie; Chen, Chi; Shao, Zongping; Ciucci, Francesco

    2015-03-01

    Oriented PrBaCo2O5+δ (PBC) thin films are prepared on yttria-stabilized ZrO2 (YSZ) substrates with orientations (001), (110) and (111) via pulsed laser deposition (PLD). Electrochemical impedance spectroscopy (EIS) experiments at various temperatures and oxygen partial pressures reveal a good oxygen reduction reaction (ORR) performance of all the thin films. However, the films' performance has considerable variance. PBC thin film deposited on (111) oriented YSZ had the best performance, followed by (110) and (001). Experiments including high resolution X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and computation, namely molecular dynamics (MD), are used to elucidate the substrate-determined orientations, examine the morphology and composition of the thin films, and to explain the variance of the ORR performance. Our results support the anisotropy of the oxygen vacancy pathway in the a-b plane and indicate that the substrate orientations can have great influence on the thin films properties.

  5. Very thin poly-SiC films for micro/nano devices.

    PubMed

    Fu, Xiao-An; Noh, Sangsoo; Chen, Li; Mehregany, Mehran

    2008-06-01

    We report characterization of nitrogen-doped, very thin, low-stress polycrystalline silicon carbide (poly-SiC) films suitable for fabricating micro/nano devices. The poly-SiC films are deposited on 100 mm-diameter (100) silicon wafers in a large-scale, hot-wall, horizontal LPCVD furnace using SiH2Cl2 and C2H2 as precursors and NH, as doping gas. The deposition temperature and pressure are fixed at 900 degrees C and 4 Torr, respectively. The deposition rate increases substantially in the first 50 minutes, transitioning to a limiting value thereafter. The deposited films exhibit (111)-orientated polycrystalline 3C-SiC texture. HR-TEM indicates a 1 nm to 4 nm amorphous SiC layer at the SiC/silicon interface. The residual stress and the resistivity of the films are found to be thickness dependent in the range of 100 nm to 1 microm. Films with thickness less than 100 nm suffer from voids or pinholes. Films thicker than 100 nm are shown to be suitable for fabricating micro/nano devices. PMID:18681047

  6. Cadmium telluride films for lightweight solar cells for space and terrestrial applications

    SciTech Connect

    Singh, V.P.; Lush, G.B.; Santiesteban, R.; McClure, J.C.; Chavez, H.

    1995-01-25

    Deposition of cadmium telluride (CdTe) films on steel foil substrates was investigated. Adherent CdTe films were vacuum evaporated and a growth rate of 3 nm/sec was obtained at a substrate temperature of 533 K. As deposited films exhibited a preferred (111) orientation. A tellurium interlayer between CdTe and steel yielded larger grains in CdTe than a gold interlayer. Annealing of CdTe films at 823 K increased the grain size and reduced the film resistance; it also tended to transform p-type CdTe into n-type. This was attributed to the diffusion of tellurium from CdTe into steel and diffusion of iron from the steel substrate into the CdTe film. This diffusion was observed using energy dispersive X-ray analysis. A photovoltage was obtained by depositing CdS on top of p-CdTe and a V{sub oc} of 360 mV was obtained. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

  7. Perovskite BiFeO3 thin film photocathode performance with visible light activity

    NASA Astrophysics Data System (ADS)

    Yilmaz, P.; Yeo, D.; Chang, H.; Loh, L.; Dunn, S.

    2016-08-01

    Perovskite materials are now an important class of materials in the application areas of photovoltaics and photocatalysis. Inorganic perovskites such as BiFeO3 (BFO) are promising photocatalyst materials with visible light activity and inherent stability. Here we report the large area sol-gel synthesis of BFO films for solar stimulated water photo oxidation. By modifying the sol-gel synthesis process we have produced a perovskite material that has p-type behaviour and a flat band potential of ∼1.15 V (versus NHE). The photocathode produces a density of ‑0.004 mA cm‑2 at 0 V versus NHE under AM1.5 G illumination. We further show that 0.6 μmol h‑1 of O2 was produced at an external bias of ‑0.5 V versus Ag/AgCl. The addition of a non-percolating conducting network of Ag increases the photocurrent to ‑0.07 mA cm‑2 at 0 V versus NHE (at 2% Ag loading) with an increase to 2.7 μmol h‑1 for O2 production. We attribute the enhancement in photoelectrochemical performance to increased light absorption due light scattering by the incorporated Ag particles, improved charge transfer kinetics at the Ag/BFO interface and reduced over potential losses. We support these claims by an observed shift in flat band and onset potentials after Ag modification through UV–vis spectroscopy, Mott–Schottky plots and j–v curve analysis.

  8. Perovskite BiFeO3 thin film photocathode performance with visible light activity.

    PubMed

    Yilmaz, P; Yeo, D; Chang, H; Loh, L; Dunn, S

    2016-08-26

    Perovskite materials are now an important class of materials in the application areas of photovoltaics and photocatalysis. Inorganic perovskites such as BiFeO3 (BFO) are promising photocatalyst materials with visible light activity and inherent stability. Here we report the large area sol-gel synthesis of BFO films for solar stimulated water photo oxidation. By modifying the sol-gel synthesis process we have produced a perovskite material that has p-type behaviour and a flat band potential of ∼1.15 V (versus NHE). The photocathode produces a density of -0.004 mA cm(-2) at 0 V versus NHE under AM1.5 G illumination. We further show that 0.6 μmol h(-1) of O2 was produced at an external bias of -0.5 V versus Ag/AgCl. The addition of a non-percolating conducting network of Ag increases the photocurrent to -0.07 mA cm(-2) at 0 V versus NHE (at 2% Ag loading) with an increase to 2.7 μmol h(-1) for O2 production. We attribute the enhancement in photoelectrochemical performance to increased light absorption due light scattering by the incorporated Ag particles, improved charge transfer kinetics at the Ag/BFO interface and reduced over potential losses. We support these claims by an observed shift in flat band and onset potentials after Ag modification through UV-vis spectroscopy, Mott-Schottky plots and j-v curve analysis. PMID:27420393

  9. Unraveling the magnetic properties of BiFe{sub 0.5}Cr{sub 0.5}O{sub 3} thin films

    SciTech Connect

    Vinai, G.; Petrov, A. Yu.; Panaccione, G.; Torelli, P.; Khare, A.; Rana, D. S.; Di Gennaro, E.; Scotti di Uccio, U.; Miletto Granozio, F.; Gobaut, B.; Moroni, R.; Rossi, G.

    2015-11-01

    We investigate the structural, chemical, and magnetic properties on BiFe{sub 0.5}Cr{sub 0.5}O{sub 3} (BFCO) thin films grown on (001) (110) and (111) oriented SrTiO{sub 3} (STO) substrates by x-ray magnetic circular dichroism and x-ray diffraction. We show how highly pure BFCO films, differently from the theoretically expected ferrimagnetic behavior, present a very weak dichroic signal at Cr and Fe edges, with both moments aligned with the external field. Chemically sensitive hysteresis loops show no hysteretic behavior and no saturation up to 6.8 T. The linear responses are induced by the tilting of the Cr and Fe moments along the applied magnetic field.

  10. Transport Properties Of Fe3-xTixO4 (x = 0.0 and 0.0206) Epitaxial Thin Films

    NASA Astrophysics Data System (ADS)

    Varshney, Dinesh; Yogi, Arvind; Verma, K.; Phase, D. M.

    2011-07-01

    Fe3-xTixO4 (x = 0 and 0.0206) epitaxial thin films with thickness of 150 nm were prepared by pulsed-laser deposition technique on SrTiO3 (100), α-Al2O3 (0001), Si (111) and Float Glass substrates. X-ray diffraction (XRD) pattern infers that parent and Ti doped magnetites are grown in single phase with (111) orientation. The Verwey transition temperature for Fe3O4 thin films are 121 K (Float Glass), 123 K (SrTiO3), 123.5 K (α-Al2O3) and 128 K (Si). It is shown that the Ti doping at B site results in the disappearance of Verwey transition in {Tix4+Fe1-x3+Fe2+}O42-.

  11. Highly oriented polycrystalline Cu{sub 2}O film formation using RF magnetron sputtering deposition for solar cells

    SciTech Connect

    Noda, S.; Shima, H.; Akinaga, H.

    2014-02-20

    Room temperature sputtering deposition and re-crystallization of the deposited thin films by rapid thermal annealing have been evaluating in detail as a formation method of Cu{sub 2}O active layer for solar cells, which minimize thermal budget in fabrication processes. Single phase polycrystalline Cu{sub 2}O films were obtained by a magnetron rf sputtering deposition and its crystallinity and electrical characteristics were controlled by the annealing. Hall mobility was improved up to 17 cm{sup 2}V{sup −1}s{sup −1} by the annealing at 600°C for 30s. Since this value was smaller than 47 cm{sup 2}V{sup −1}s{sup −1} of the film deposited under thermal equilibrium state using pulsed laser deposition at 600°C, some contrivances were necessary to compensate the deficiency. It was understood that the sputter-deposited Cu{sub 2}O films on (111)-oriented Pt films were strongly oriented to (111) face also by the self-assembly and the crystallinity was improved by the annealing preserving its orientation. The sputter-deposited film quality was expected to become equivalent to the pulsed laser deposition film from the results of X-ray diffractometry and photoluminescence.

  12. Switching dynamics of thin film ferroelectric devices - a massively parallel phase field study

    NASA Astrophysics Data System (ADS)

    Ashraf, Md. Khalid

    In this thesis, we investigate the switching dynamics in thin film ferroelectrics. Ferroelectric materials are of inherent interest for low power and multi-functional devices. However, possible device applications of these materials have been limited due to the poorly understood electromagnetic and mechanical response at the nanoscale in arbitrary device structures. The difficulty in understanding switching dynamics mainly arises from the presence of features at multiple length scales and the nonlinearity associated with the strongly coupled states. For example, in a ferroelectric material, the domain walls are of nm size whereas the domain pattern forms at micron scale. The switching is determined by coupled chemical, electrostatic, mechanical and thermal interactions. Thus computational understanding of switching dynamics in thin film ferroelectrics and a direct comparison with experiment poses a significant numerical challenge. We have developed a phase field model that describes the physics of polarization dynamics at the microscopic scale. A number of efficient numerical methods have been applied for achieving massive parallelization of all the calculation steps. Conformally mapped elements, node wise assembly and prevention of dynamic loading minimized the communication between processors and increased the parallelization efficiency. With these improvements, we have reached the experimental scale - a significant step forward compared to the state of the art thin film ferroelectric switching dynamics models. Using this model, we elucidated the switching dynamics on multiple surfaces of the multiferroic material BFO. We also calculated the switching energy of scaled BFO islands. Finally, we studied the interaction of domain wall propagation with misfit dislocations in the thin film. We believe that the model will be useful in understanding the switching dynamics in many different experimental setups incorporating thin film ferroelectrics.

  13. Structural characterization of InSb thin films grown by electrodeposition

    SciTech Connect

    Singh, Joginder Rajaram, P.

    2015-06-24

    In the present work we have grown InSb thin films on brass substrates, using the electrodeposition technique. The electrochemical baths used in the growth were made up of aqueous solutions of InCl{sub 3} and SbCl{sub 3} mixed together in various proportions. The films grown were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Analysis of X-rays (EDAX). Compositional studies show that stoichiometric InSb films can be prepared from a bath containing 0.05M InCl{sub 3} and 0.04M SbCl{sub 3}. XRD studies reveal that the films grown are polycrystalline having the zinc blende structure with (111) orientation. Crystallite size, dislocation density and strain were calculated using the XRD results. Optical transmission spectra were recorded using an FTIR spectrophotometer. The value of direct band gap was found to be around 0.20 eV for the thin films having the best stoichiometry.

  14. Structure and strain relaxation mechanisms of ultrathin epitaxial Pr2O3 films on Si(111)

    NASA Astrophysics Data System (ADS)

    Schroeder, T.; Lee, T.-L.; Libralesso, L.; Joumard, I.; Zegenhagen, J.; Zaumseil, P.; Wenger, C.; Lupina, G.; Lippert, G.; Dabrowski, J.; Müssig, H.-J.

    2005-04-01

    The structure of ultrathin epitaxial Pr2O3 films on Si(111) was studied by synchrotron radiation-grazing incidence x-ray diffraction. The oxide film grows as hexagonal Pr2O3 phase with its (0001) plane attached to the Si(111) substrate. The hexagonal (0001) Pr2O3 plane matches the in-plane symmetry of the hexagonal Si(111) surface unit cell by aligning the ⟨101¯0⟩Pr2O3 along the ⟨112¯⟩ Si directions. The small lattice mismatch of 0.5% results in the growth of pseudomorphic oxide films of high crystalline quality with an average domain size of about 50 nm. The critical thickness tc for pseudomorphic growth amounts to 3.0±0.5nm. The relaxation of the oxide film from pseudomorphism to bulk behavior beyond tc causes the introduction of misfit dislocations, the formation of an in-plane small angle mosaicity structure, and the occurence of a phase transition towards a (111) oriented cubic Pr2O3 film structure. The observed phase transition highlights the influence of the epitaxial interface energy on the stability of Pr2O3 phases on Si(111). A mechanism is proposed which transforms the hexagonal (0001) into the cubic (111) Pr2O3 epilayer structure by rearranging the oxygen network but leaving the Pr sublattice almost unmodified.

  15. Spectroscopy and Dynamics of a Two-Dimensional Electron Gas on Ultrathin Helium Films on Cu(111).

    PubMed

    Armbrust, N; Güdde, J; Höfer, U; Kossler, S; Feulner, P

    2016-06-24

    Electrons in image-potential states on the surface of bulk helium represent a unique model system of a two-dimensional electron gas. Here, we investigate their properties in the extreme case of reduced film thickness: a monolayer of helium physisorbed on a single-crystalline (111)-oriented Cu surface. For this purpose we have utilized a customized setup for time-resolved two-photon photoemission at very low temperatures under ultrahigh vacuum conditions. We demonstrate that the highly polarizable metal substrate increases the binding energy of the first (n=1) image-potential state by more than 2 orders of magnitude as compared to the surface of liquid helium. An electron in this state is still strongly decoupled from the metal surface due to the large negative electron affinity of helium and we find that even 1 monolayer of helium increases its lifetime by 1 order of magnitude compared to the bare Cu(111) surface. PMID:27391738

  16. Spectroscopy and Dynamics of a Two-Dimensional Electron Gas on Ultrathin Helium Films on Cu(111)

    NASA Astrophysics Data System (ADS)

    Armbrust, N.; Güdde, J.; Höfer, U.; Kossler, S.; Feulner, P.

    2016-06-01

    Electrons in image-potential states on the surface of bulk helium represent a unique model system of a two-dimensional electron gas. Here, we investigate their properties in the extreme case of reduced film thickness: a monolayer of helium physisorbed on a single-crystalline (111)-oriented Cu surface. For this purpose we have utilized a customized setup for time-resolved two-photon photoemission at very low temperatures under ultrahigh vacuum conditions. We demonstrate that the highly polarizable metal substrate increases the binding energy of the first (n =1 ) image-potential state by more than 2 orders of magnitude as compared to the surface of liquid helium. An electron in this state is still strongly decoupled from the metal surface due to the large negative electron affinity of helium and we find that even 1 monolayer of helium increases its lifetime by 1 order of magnitude compared to the bare Cu(111) surface.

  17. Comparative study of magnetite (Fe3O4) thin films grown by pulsed laser ablation and sputtering

    NASA Astrophysics Data System (ADS)

    Bohra, Murtaza; Varun Karthik Y., S.; Haveesh, G.; Tarun Y. S., N.; Prasad, D. V. B.; Chowdhury, D. Roy; Prasad, K. Eswar

    2016-05-01

    Comparative study of magnetite (Fe3O4) thin films grown by pulsed laser ablation (PLD) and radio frequency (RF)-sputtering of α-Fe2O3 target have been investigated. We have found strong correlation between RF power (P) of sputtering and substrate temperature (Ts) of PLD films on their structural and magnetic properties. Films grown at low P and Ts are dominated by antiferromagnetic α-Fe2O3 phase while ferrimagnetic Fe3O4 phase is dominant at high P and Ts Post-annealing in H2/H2O atmosphere at 450 °C, these films show single phase Fe3O4 but RF power and substrate temperature still play a significant role. With increasing P and Ts values, the orientation of Fe3O4 films change from (110) to (111) followed by complete randomizations. These (110) to (111) orientations affect magnetic properties differently above Verwey transition temperature of 120 K. The RF-power and substrate temperature have the same influence on the physical properties of Fe3O4 films, as both are related to thermal energy.

  18. Characterization of CdMnTe films deposited from polycrystalline powder source using closed-space sublimation method

    SciTech Connect

    Lai, Jianming; Wang, Junnan; Wang, Lin; Ji, Huanhuan; Xu, Run; Zhang, Jijun; Huang, Jian; Shen, Yue; Min, Jiahua; Wang, Linjun Xia, Yiben

    2015-09-15

    CdMnTe films were prepared on quartz substrates by closed-space sublimation of polycrystalline Cd{sub 0.74}Mn{sub 0.26}Te powders. This was performed at different substrate temperatures (T{sub s} = 200, 300, 350, and 400 °C). The interfacial adhesion strength between the films and substrates, when fabricated from polycrystalline powders, was greater than that of films grown using a bulk source. X-ray diffraction studies revealed that the as-deposited films had a zinc blende structure with a preferential (111) orientation. Precipitation of Te occurred in the films deposited at T{sub s} = 200 °C, as confirmed using scanning electron microscopy, x-ray diffraction, and Raman spectroscopy. The growth mode and re-evaporation dependence on the value of T{sub s} of the films were investigated. Our results suggested that materials suitable for radiation detection can be grown from a powder source at lower substrate temperatures then when grown from a bulk source.

  19. Mn-Doped BaTiO3 Thin Film Sintered Using Nanocrystals and Its Dielectric Properties

    NASA Astrophysics Data System (ADS)

    Takezawa, Yoko; Kobayashi, Keisuke; Nakasone, Fumi; Suzuki, Toshimasa; Mizuno, Youichi; Imai, Hiroaki

    2009-11-01

    BaTiO3 thin films homogeneously doped with Mn were prepared by a novel powder-sintering thin-film process. Mn-doped BaTiO3 nanocrystals 5-7 nm in diameter were synthesized by a sol-gel method and sintered to form a highly densified microstructure containing columnar grains epitaxially grown on a (111)-oriented Pt/TiO2/Al2O3 substrate at a low temperature of 800 °C. On the basis of the results of various structural analyses, Mn was suggested to act as an acceptor in the perovskite structure of BaTiO3, which was also supported by the experimental finding indicating that the leakage current density was significantly improved compared with that of a nondoped BaTiO3 thin film. Moreover, the dielectric constant of the Mn-doped BaTiO3 thin film, 728 at 10 kHz with a loss tangent of 1.3%, was higher than that of the nondoped BaTiO3 thin film, probably owing to the electrostrictive effect induced by in-plane tensile stress. These results clearly indicate the feasibility of using doped BaTiO3 nanocrystals in the powder-sintering thin-film process for improving dielectric properties.

  20. Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties

    NASA Astrophysics Data System (ADS)

    Sokolov, N. S.; Fedorov, V. V.; Korovin, A. M.; Suturin, S. M.; Baranov, D. A.; Gastev, S. V.; Krichevtsov, B. B.; Maksimova, K. Yu.; Grunin, A. I.; Bursian, V. E.; Lutsev, L. V.; Tabuchi, M.

    2016-01-01

    Pulsed laser deposition has been used to grow thin (10-84 nm) epitaxial layers of Yttrium Iron Garnet Y3Fe5O12 (YIG) on (111)-oriented Gadolinium Gallium Garnet substrates at different growth conditions. Atomic force microscopy showed flat surface morphology both on micrometer and nanometer scales. X-ray diffraction measurements revealed that the films are coherent with the substrate in the interface plane. The interplane distance in the [111] direction was found to be by 1.2% larger than expected for YIG stoichiometric pseudomorphic film indicating presence of rhombohedral distortion in this direction. Polar Kerr effect and ferromagnetic resonance measurements showed existence of additional magnetic anisotropy, which adds to the demagnetizing field to keep magnetization vector in the film plane. The origin of the magnetic anisotropy is related to the strain in YIG films observed by XRD. Magneto-optical Kerr effect measurements revealed important role of magnetization rotation during magnetization reversal. An unusual fine structure of microwave magnetic resonance spectra has been observed in the film grown at reduced (0.5 mTorr) oxygen pressure. Surface spin wave propagation has been demonstrated in the in-plane magnetized films.

  1. Morphology and microstructure of (111) crystalline CeO{sub 2} films grown on amorphous SiO{sub 2} substrates by pulsed-laser ablation

    SciTech Connect

    Zhu, S.; Lowndes, D.H.; Budai, J.D.; Thundat, T.; Norton, D.P.; Warmack, R.J.

    1994-11-01

    The surface morphology and microstructure of (111)-oriented CeO{sub 2} thin films, grown on amorphous fused silica (SiO{sub 2} substrates by low-energy-ion-beam assisted pulsed laser ablation, have been studied by atomic force microscopy (AFM) and x-ray diffraction (XRD). These CeO{sub 2} films are aligned with respect to a single in-plane axis despite being deposited on an amorphous substrate. There is a honeycomb-like growth morphology to the films and island-growth can be observed in thicker films. These islands, inside of which are high density of honeycomb-like clusters, are separated by a void network with {approximately}700 nm width. However, on the surface of the thinnest film ({approximately}3 nm), only very small clusters (diameter <60 nm) appear, and the boundaries of the void network are undefined, which implies that the film is just beginning to coalesce into clusters (grains). The combined AFM images and XRD pattern suggest these clusters probably are the initial seeds for the subsequent island growth. Based on these results, the growth mechanism of oriented CeO{sub 2} films on amorphous fused silica substrates is discussed.

  2. Effects of Post-Deposition Annealing on the Copper Films Electrodeposited on the ECR Plasma Cleaned Copper Seed Layer

    NASA Astrophysics Data System (ADS)

    Lee, Hanseung; Chakrabarti, Kuntal; Lee, Chongmu

    2002-12-01

    Thin copper films were grown by electrodeposition on copper seed layers which were grown by sputtering of an ultra-pure copper target on tantalum nitride-coated silicon wafers and subsequently, cleaned in ECR plasma. The copper films were then subjected to i) vacuum annealing, ii) rapid thermal annealing (RTA) and iii) rapid thermal nitriding (RTN) at various temperatures over different periods of time. XRD, SEM, AFM and resistivity measurements were done to ascertain the optimum heat treatment condition for obtaining film with minimum resistivity, predominantly (111)-oriented and smoother surface morphology. The as-deposited film has a resistivity of ˜6.3 μΩ\\cdotcm and a relatively small intensity ratio of (111) and (200) peaks. With heat treatment, the resistivity decreases and the (111) peak becomes dominant, along with improved smoothness of the copper film. The optimum condition (with a resistivity of 1.98 μΩ\\cdotcm) is suggested as the rapid thermal nitriding at 400°C for 120 s.

  3. In situ x-ray scattering study of the passive film on Ni(III) in sulfuric acid solution

    SciTech Connect

    Magnussen, O.M.; Scherer, J.; Ocko, B.M.; Behm, R.J.

    2000-02-17

    Results of an in situ X-ray scattering study of the passive film formed on Ni(111) electrodes by passivation in 0.05 M H{sub 2}SO{sub 4} (pH 1.0) at 0.50 V{sub Ag/AgCl} are reported and compared with results on the film formed by oxidation in air at room temperature. In both cases, ultrathin, (111)-oriented NiO films are observed, which are aligned with the Ni substrate lattice and slightly expanded along the surface normal with respect to bulk NiO. However, two major structural differences are found: (1) while on the air-formed oxide parallel (NiO-[1{bar 1}0] {parallel} Ni[1{bar 1}0]) and antiparallel (NiO[1{bar 1}0] {parallel} Ni[{bar 1}10]) oriented domains coexist, the passive film exhibits a well-defined antiparallel orientation and (2) the lattice of the passive film is, in contrast to that of the air-formed oxide, tilted relative to the substrate with a broad angular dispersion of the tilt angle centered at about 3.3{degree}.

  4. Orientation epitaxy of Ge1–xSnx films grown on single crystal CaF2 substrates

    DOE PAGESBeta

    A. J. Littlejohn; Zhang, L. H.; Lu, T. -M.; Kisslinger, K.; and Wang, G. -C.

    2016-03-15

    Ge1–xSnx films were grown via physical vapor deposition below the crystallization temperature of Ge on single crystal (111) and (100) CaF2 substrates to assess the role of Sn alloying in Ge crystallization. By studying samples grown at several growth temperatures ranging from 250 °C to 400 °C we report temperature-dependent trends in several of the films' properties. X-ray diffraction theta vs. two-theta (θ/2θ) scans indicate single orientation Ge1–xSnx(111) films are grown on CaF2(111) substrates at each temperature, while a temperature-dependent superposition of (111) and (100) orientations are exhibited in films grown on CaF2(100) above 250 °C. This is the firstmore » report of (111) oriented Ge1–xSnx grown on a (100) oriented CaF2 substrate, which is successfully predicted by a superlattice area matching model. These results are confirmed by X-ray diffraction pole figure analysis. θ/2θ results indicate substitutional Sn alloying in each film of about 5%, corroborated by energy dispersive spectroscopy. In addition, morphological and electrical properties are measured by scanning electron microscopy, atomic force microscopy and Hall mobility measurements and are also shown to be dependent upon growth temperature.« less

  5. Direct Observation of Magnetic Field Induced Ferroelectric Domain Evolution in Self-Assembled Quasi (0-3) BiFeO3-CoFe2O4 Thin Films.

    PubMed

    Li, Linglong; Lu, Lu; Zhang, Dawei; Su, Ran; Yang, Guang; Zhai, Junyi; Yang, Yaodong

    2016-01-13

    Strain-mediated magnetoelectric (ME) coupling effect is expected in self-assembly heterostructures engineered by ferroelectric and ferromagnetic materials, contributing to the enhanced overall magnetoelectric effect. Microstructures as well as the connectivity configuration are considered to play a significant role in achieving efficient magnetoelectric properties. Different from the conventional (1-3) and (2-2) type composite films, we fabricate BiFeO3-CoFe2O4 (BFO-CFO) composite thin films with a novel quasi (0-3) type connectivity via a dual-target pulsed laser deposition process. The self-assembly growth mechanism has been studied, which demonstrates that the perovskite (BFO) matrix segments the connectivity of spinel (CFO) resulting in a quasi (0-3) composite. Direct observation of ferroelectric domain wall motion under external magnetic fields proves a strong magnetoelectric coupling effect in these (0-3) thin films. Our preliminary findings reveal the promising application potential of this new structure as multiferroic domain wall devices. PMID:26698906

  6. Growth and characterization of Bi, Pr- and Bi, Sc-substituted lutetium iron garnet films with planar magnetization for magneto-optic visualization

    NASA Astrophysics Data System (ADS)

    Syvorotka, Igor M.; Ubizskii, Sergii B.; Kucera, Miroslav; Kuhn, Marcus; Vértesy, Zofia

    2001-04-01

    The series of epitaxial garnet films of general composition Lu3-x-yBixPryFe5- zAlzO12 and Lu3-xBixFe5-y- zScyAlzO12 were grown on (111) oriented GGG (gadolinium gallium garnet) substrates by the liquid phase epitaxy. Their magnetic and magneto-optical properties were studied using both experimental techniques and modelling. All obtained films demonstrated generally a magnetic anisotropy close to the easy-plane type. The Pr-containing films exhibited large negative uniaxial anisotropy and significant cubic anisotropy. The latter causes a distortion of magnetization curves in samples magnetized in a direction normal to the film plane, especially at low temperatures. The large negative uniaxial anisotropy of Pr-substituted iron garnets allows us to increase the saturation field up to 0.5 T at liquid nitrogen temperature. The Sc-doped films displayed small positive uniaxial anisotropy that did not exceed the shape anisotropy. The magnetization curves of these films did not show any distortion due to the cubic anisotropy. The suitability of Pr- and Sc-doped garnets that meet the requirements for indicator layers for magneto-optic visualization at liquid nitrogen temperature is discussed.

  7. Effects of nonequilibrium growth, nonstoichiometry, and film orientation on the metal-to-insulator transition in NdNiO₃ thin films.

    PubMed

    Breckenfeld, Eric; Chen, Zuhuang; Damodaran, Anoop R; Martin, Lane W

    2014-12-24

    Next-generation devices will rely on exotic functional properties not found in traditional systems. One class of materials of particular interest for applications are those possessing metal-to-insulator transitions (MITs). In this work, we probe the relationship between variations in the growth process, subsequent variations in cation stoichiometry, and the MIT in NdNiO3 thin films. Slight variations in the growth conditions, in particular the laser fluence, during pulsed-laser deposition growth of NdNiO3 produces films that are both single-phase and coherently strained to a range of substrates despite possessing as much as 15% Nd-excess. Subsequent study of the temperature-dependence of the electronic transport reveals dramatic changes in both the onset and magnitude of the resistivity change at the MIT with increasing cation nonstoichiometry giving rise to a decrease (and ultimately a suppression) of the transition and the magnitude of the resistivity change. From there, the electronic transport of nearly ideal NdNiO3 thin films are studied as a function of epitaxial strain, thickness, and orientation. Overall, transitioning from tensile to compressive strain results in a systematic reduction of the onset and magnitude of the resistivity change across the MIT, thinner films are found to possess sharper MITs with larger changes in the resistivity at the transition, and (001)-oriented films exhibit sharper and larger MITs as compared to (110)- and (111)-oriented films as a result of highly anisotropic in-plane transport in the latter. PMID:25454898

  8. Electric control of magnon frequencies and magnetic moment of bismuth ferrite thin films at room temperature

    PubMed Central

    Kumar, Ashok; Scott, J. F.; Katiyar, R. S.

    2011-01-01

    Here, we report the tuning of room-temperature magnon frequencies from 473 GHz to 402 GHz (14%) and magnetic moment from 4 to 18 emu∕cm3 at 100 Oe under the application of external electric fields (E) across interdigital electrodes in BiFeO3 (BFO) thin films. A decrease in magnon frequencies and increase in phonon frequencies were observed with Magnon and phonon Raman intensities are asymmetric with polarity, decreasing with positive E (+E) and increasing with negative E (−E) where polarity is with respect to in-plane polarization P. The magnetoelectric coupling (α) is proved to be linear and a rather isotropic α = 8.5 × 10−12 sm−1. PMID:21901050

  9. Microstructural characterization in nanocrystalline ceramic thin films

    NASA Astrophysics Data System (ADS)

    Kim, Hakkwan

    The primary objective of this research is to investigate the effects of process variables on microstructure in several fluoride and oxide thin films prepared by vapor deposition, in order to predict the properties and behaviors of nanocrystalline thin film materials. There are three distinct stages of this research. The first stage focuses on measuring of the porosity in polycrystalline thin films of a variety of fluorides as a function of the substrate temperature during deposition, and discussing the mechanism by which the porosity varies as a function of the process variables. We have measured the porosity in thin films of lithium fluoride (LiF), magnesium fluoride (MgF2), barium fluoride (BaF 2) and calcium fluoride (CaF2) using an atomic force microscope (AFM) and a quartz crystal thickness monitor. The porosity is very sensitive to the substrate temperature and decreases as the substrate temperature increases. Consistent behavior is observed among all of the materials in this study. The second stage is to understand the film microstructure including grain growth and texture development, because these factors are known to influence the behavior and stability of polycrystalline thin films. This study focuses on grain growth and texture development in polycrystalline lithium fluoride thin films using dark field (DF) transmission electron microscopy (TEM). It is demonstrated that we can isolate the size distribution of <111> surface normal grains from the overall size distribution, based on simple and plausible assumptions about the texture. The {111} texture formation and surface morphology were also observed by x-ray diffraction (XRD) and AFM, respectively. The grain size distributions become clearly bimodal as the annealing time increases, and we deduce that the short-time size distributions are also a sum of two overlapping peaks. The smaller grain-size peak in the distribution corresponds to the {111}-oriented grains which do not grow significantly, while

  10. Film Reviews.

    ERIC Educational Resources Information Center

    Lance, Larry M.; Atwater, Lynn

    1987-01-01

    Reviews four Human Sexuality films and videos. These are: "Personal Decisions" (Planned Parenthood Federation of America, 1985); "The Touch Film" (Sterling Production, 1986); "Rethinking Rape" (Film Distribution Center, 1985); "Not A Love Story" (National Film Board of Canada, 1981). (AEM)

  11. Growth, structure, and properties of BiFeO3/-BiCrO3 films obtained by dual cross beam PLD.

    PubMed

    Nechache, Riad; Harnagea, Catalin; Gunawan, Lina; Carignan, Louis-Philipe; Maunders, Christian; Ménard, David; Botton, Gianluigi A; Pignolet, Alain

    2007-12-01

    The properties of epitaxial Bi(2)FeCrO(6) thin films, recently synthesized by pulsed laser deposition, have partially confirmed the theoretical predictions (i.e., a magnetic moment of 2 micro(B) per formula unit and a polarization of approximately 80 microC/cm(2) at 0 K). The existence of magnetic ordering at room temperature for this material is an unexpected, but very promising, result that needs to be further investigated. Because magnetism is assumed to arise from the exchange interaction between the Fe and Cr cations, the magnetic behavior is strongly dependent on both their ordering and the distance between them. We present here the successful synthesis of epitaxial Bi(2)Fe(x)CryO(6) (BFCO x/y) films grown on SrTiO3 substrates using dual crossed-beam, pulsed-laser deposition. The crystal structure of the films has different types of (111)-oriented superstructures, depending on the deposition conditions. The multiferroic character of BFCO (x/y) films is proven by the presence of both ferroelectric and magnetic hysteresis at room temperature. The oxidation state of Fe and Cr ions in the films is shown to be 3+ only, and the difference in macroscopic magnetization with Fe/Cr ratio composition could only be due to ordering of the Cr(3+) and Fe(3+) cations to the modification of the exchange interaction between them. PMID:18276571

  12. Switching of magnetic easy-axis using crystal orientation for large perpendicular coercivity in CoFe2O4 thin film

    PubMed Central

    Shirsath, Sagar E.; Liu, Xiaoxi; Yasukawa, Yukiko; Li, Sean; Morisako, Akimitsu

    2016-01-01

    Perpendicular magnetization and precise control over the magnetic easy axis in magnetic thin film is necessary for a variety of applications, particularly in magnetic recording media. A strong (111) orientation is successfully achieved in the CoFe2O4 (CFO) thin film at relatively low substrate temperature of 100 °C, whereas the (311)-preferred randomly oriented CFO is prepared at room temperature by the DC magnetron sputtering technique. The oxygen-deficient porous CFO film after post-annealing gives rise to compressive strain perpendicular to the film surface, which induces large perpendicular coercivity. We observe the coercivity of 11.3 kOe in the 40-nm CFO thin film, which is the highest perpendicular coercivity ever achieved on an amorphous SiO2/Si substrate. The present approach can guide the systematic tuning of the magnetic easy axis and coercivity in the desired direction with respect to crystal orientation in the nanoscale regime. Importantly, this can be achieved on virtually any type of substrate. PMID:27435010

  13. Optical and magneto-optical behavior of Cerium Yttrium Iron Garnet thin films at wavelengths of 200–1770 nm

    PubMed Central

    Onbasli, Mehmet C.; Beran, Lukáš; Zahradník, Martin; Kučera, Miroslav; Antoš, Roman; Mistrík, Jan; Dionne, Gerald F.; Veis, Martin; Ross, Caroline A.

    2016-01-01

    Magneto-optical cerium-substituted yttrium iron garnet (Ce:YIG) thin films display Faraday and Kerr rotation (rotation of light polarisation upon transmission and reflection, respectively) as well as a nonreciprocal phase shift due to their non-zero off-diagonal permittivity tensor elements, and also possess low optical absorption in the near-infrared. These properties make Ce:YIG useful in providing nonreciprocal light propagation in integrated photonic circuits, which is essential for accomplishing energy-efficient photonic computation and data transport architectures. In this study, 80 nm-thick Ce:YIG films were grown on Gadolinium Gallium Garnet substrates with (100), (110) and (111) orientations using pulsed laser deposition. The films had bulk-like structural and magnetic quality. Faraday and Kerr spectroscopies along with spectroscopic ellipsometry were used to deduce the complete permittivity tensor of the films in the ultraviolet, visible and near-infrared spectral region, and the magneto-optical figure of merit as a function of wavelength was determined. The samples showed the highest IR Faraday rotation reported for thin films of Ce:YIG, which indicates the importance of this material in development of nonreciprocal photonic devices. PMID:27025269

  14. Switching of magnetic easy-axis using crystal orientation for large perpendicular coercivity in CoFe2O4 thin film.

    PubMed

    Shirsath, Sagar E; Liu, Xiaoxi; Yasukawa, Yukiko; Li, Sean; Morisako, Akimitsu

    2016-01-01

    Perpendicular magnetization and precise control over the magnetic easy axis in magnetic thin film is necessary for a variety of applications, particularly in magnetic recording media. A strong (111) orientation is successfully achieved in the CoFe2O4 (CFO) thin film at relatively low substrate temperature of 100 °C, whereas the (311)-preferred randomly oriented CFO is prepared at room temperature by the DC magnetron sputtering technique. The oxygen-deficient porous CFO film after post-annealing gives rise to compressive strain perpendicular to the film surface, which induces large perpendicular coercivity. We observe the coercivity of 11.3 kOe in the 40-nm CFO thin film, which is the highest perpendicular coercivity ever achieved on an amorphous SiO2/Si substrate. The present approach can guide the systematic tuning of the magnetic easy axis and coercivity in the desired direction with respect to crystal orientation in the nanoscale regime. Importantly, this can be achieved on virtually any type of substrate. PMID:27435010

  15. Optical and magneto-optical behavior of Cerium Yttrium Iron Garnet thin films at wavelengths of 200–1770 nm

    NASA Astrophysics Data System (ADS)

    Onbasli, Mehmet C.; Beran, Lukáš; Zahradník, Martin; Kučera, Miroslav; Antoš, Roman; Mistrík, Jan; Dionne, Gerald F.; Veis, Martin; Ross, Caroline A.

    2016-03-01

    Magneto-optical cerium-substituted yttrium iron garnet (Ce:YIG) thin films display Faraday and Kerr rotation (rotation of light polarisation upon transmission and reflection, respectively) as well as a nonreciprocal phase shift due to their non-zero off-diagonal permittivity tensor elements, and also possess low optical absorption in the near-infrared. These properties make Ce:YIG useful in providing nonreciprocal light propagation in integrated photonic circuits, which is essential for accomplishing energy-efficient photonic computation and data transport architectures. In this study, 80 nm-thick Ce:YIG films were grown on Gadolinium Gallium Garnet substrates with (100), (110) and (111) orientations using pulsed laser deposition. The films had bulk-like structural and magnetic quality. Faraday and Kerr spectroscopies along with spectroscopic ellipsometry were used to deduce the complete permittivity tensor of the films in the ultraviolet, visible and near-infrared spectral region, and the magneto-optical figure of merit as a function of wavelength was determined. The samples showed the highest IR Faraday rotation reported for thin films of Ce:YIG, which indicates the importance of this material in development of nonreciprocal photonic devices.

  16. Optical and magneto-optical behavior of Cerium Yttrium Iron Garnet thin films at wavelengths of 200-1770 nm.

    PubMed

    Onbasli, Mehmet C; Beran, Lukáš; Zahradník, Martin; Kučera, Miroslav; Antoš, Roman; Mistrík, Jan; Dionne, Gerald F; Veis, Martin; Ross, Caroline A

    2016-01-01

    Magneto-optical cerium-substituted yttrium iron garnet (Ce:YIG) thin films display Faraday and Kerr rotation (rotation of light polarisation upon transmission and reflection, respectively) as well as a nonreciprocal phase shift due to their non-zero off-diagonal permittivity tensor elements, and also possess low optical absorption in the near-infrared. These properties make Ce:YIG useful in providing nonreciprocal light propagation in integrated photonic circuits, which is essential for accomplishing energy-efficient photonic computation and data transport architectures. In this study, 80 nm-thick Ce:YIG films were grown on Gadolinium Gallium Garnet substrates with (100), (110) and (111) orientations using pulsed laser deposition. The films had bulk-like structural and magnetic quality. Faraday and Kerr spectroscopies along with spectroscopic ellipsometry were used to deduce the complete permittivity tensor of the films in the ultraviolet, visible and near-infrared spectral region, and the magneto-optical figure of merit as a function of wavelength was determined. The samples showed the highest IR Faraday rotation reported for thin films of Ce:YIG, which indicates the importance of this material in development of nonreciprocal photonic devices. PMID:27025269

  17. Growth and physical properties of p-Zn x Cd1- x S thin films thermally evaporated on ITO-coated glass substrates

    NASA Astrophysics Data System (ADS)

    Yoon, Eun Jeong; Han, Dong Hun; Lee, Jeoung Ju; Lee, Jong Duk; Kang, Kwang Yong; Lee, Seung Hwan; Shewale, Prashant Shivaji

    2015-01-01

    Zn x Cd1- x S ( x = 0.15, 0.44, 0.62, 0.80, and 0.95) thin films of about 340 nm in thickness were deposited on indium-tin-oxide (ITO)-coated glass substrates by using thermal evaporation of high-purity ZnS and CdS mixed tablets in high vacuum. X-ray diffraction spectra showed that the Zn x Cd1- x S thin films were preferentially grown along the (111) orientation. The Zn x Cd1- x S crystal structure was a mixture structure of the ZnS and the CdS cubic zincblende structures with lattice constants a = 5.670 Å to a = 5.734 Å for CdS and a = 5.437 Å for ZnS. The ( αh ν)2 vs. h ν plots for the Zn x Cd1- x S thin films showed that all samples had direct transition band gaps. The energy band gaps of the Zn x Cd1- x S thin films increased monotonically from 2.45 eV for x = 0.15 to 3.37 eV for x = 0.95. The dynamical behavior of the charge carriers in the Zn x Cd1- x S thin films was investigated by using the photoinduced discharge characteristics (PIDC) technique.

  18. Atomic disorder of Li0.5Ni0.5O thin films caused by Li doping: estimation from X-ray Debye–Waller factors

    PubMed Central

    Yang, Anli; Sakata, Osami; Yamauchi, Ryosuke; Kumara, L. S. R.; Song, Chulho; Katsuya, Yoshio; Matsuda, Akifumi; Yoshimoto, Mamoru

    2015-01-01

    Cubic type room-temperature (RT) epitaxial Li0.5Ni0.5O and NiO thin films with [111] orientation grown on ultra-smooth sapphire (0001) substrates were examined using synchrotron-based thin-film X-ray diffraction. The 11 and 22 rocking curves including six respective equivalent reflections of the Li0.5Ni0.5O and NiO thin films were recorded. The RT B 1 factor, which appears in the Debye–Waller factor, of a cubic Li0.5Ni0.5O thin film was estimated to be 1.8 (4) Å2 from its 11 and 22 reflections, even though the Debye model was originally derived on the basis of one cubic element. The corresponding Debye temperature is 281 (39) K. Furthermore, the B 2 factor in the pseudo-Debye–Waller factor is proposed. This parameter, which is evaluated using one reflection, was also determined for the Li0.5Ni0.5O thin film by treating Li0.5Ni0.5O and NiO as ideal NaCl crystal structures. A structural parameter for the atomic disorder is introduced and evaluated. This parameter includes the combined effects of thermal vibration, interstitial atoms and defects caused by Li doping using the two Debye–Waller factors. PMID:26664345

  19. Structure and optical properties of polycrystalline NiO films and its resistive switching behavior in Au/NiO/Pt structures

    NASA Astrophysics Data System (ADS)

    Lai, J. C.; Wang, X. C.; Mi, W. B.; Ding, Y. H.; Yang, B. H.

    2015-12-01

    Structure and optical of polycrystalline NiO films fabricated by reactive sputtering and its resistive switching properties in Au/NiO/Pt structures are investigated. The size of surface uniform pyramid-like islands and average surface roughness increase with the increase of NiO film thickness (t). The NiO films grow with the preferred (111) orientation at 400 °C, but both (100) and (110)-oriented grains exist in the films fabricated at room temperature. Raman results reveal that the crystallinity of the films fabricated at 400 °C becomes good by comparing with that at room temperature. The optical band gap monotonically decreases from 4.44 eV at t=22 nm to 3.55 eV at t=800 nm. The resistance of the Au/NiO/Pt/Ti/glass structures could be switched between two stable states including low and high resistance states. The bipolar endurance performance of the resistive switching remains nondegradable after 200 cycles. The resistive switching can be ascribed to the carrier trapping and detrapping induced by the electric field, which can change the thickness of the depletion layer at Au/NiO interface.

  20. Microstructural and electrochemical properties of rf-sputtered LiMn2O4 thin film cathodes

    NASA Astrophysics Data System (ADS)

    Jayanth Babu, K.; Jeevan Kumar, P.; Hussain, O. M.

    2012-12-01

    Lithium transition metal oxides have received considerable attention in recent years as high voltage positive electrode materials in the fabrication of all solid state microbatteries. Among various lithium-based cathode materials, LiMn2O4 is one of the most promising cathode materials as it offers high energy density, high cell voltage, low cost, and low toxicity over the other electrode materials. Thin films of LiMn2O4 were prepared by radio frequency magnetron sputtering on gold-coated silicon substrates under various substrate temperatures ranging from 373 to 673 K in a partial pressure of 3 × 10-3 mbar with rf power 100 Watts. In the present investigation, the influence of substrate temperature on the growth and microstructural properties was studied. The films deposited at a substrate temperature less than 473 K was found to be X-ray amorphous. The initial crystallization has been observed at a substrate temperature of 523 K. The X-ray diffraction patterns of the films deposited in the substrate temperature range 523-673 K exhibited predominant (111) orientation representing cubic spinel structure with Fd3m symmetry. The grain size was found to be increased with the increase of substrate temperature as evidenced from SEM studies. However, additional impurity phases like Mn3O4 were observed for the films deposited at higher substrate temperatures (>673 K) because of re-evaporation of Li+ ions in the films. The electrochemical (EC) studies were carried for the films deposited at T s = 673 K in aqueous media in the potential window of 0.0-1.2 V exhibited better electrochemical performance suggesting that the films are well suited as binder free thin film cathode material for commercially viable Li-ion secondary batteries.

  1. Surfactant assisted growth of MgO films on GaN

    SciTech Connect

    Paisley, Elisibeth A.; Shelton, T C; Mita, S; Gaddy, Brian E.; Irving, D L; Christen, Hans M; Sitar, Z; Biegalski, Michael D; Maria, Jon Paul

    2012-01-01

    Thin epitaxial films of <111> oriented MgO on [0001]-oriented GaN were grown by molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) using the assistance of a vapor phase surfactant. In both cases, surfactant incorporation enabled layer-by-layer growth and a smooth terminal surface due to stabilizing the {111} rocksalt facet. MBE growth of MgO in water terminates after several monolayers, and is attributed to saturation of surface active sites needed to facilitate the Mg oxidation reaction. MgO films prepared by PLD grow continuously, this occurs due to the presence of excited oxidizing species in the laser plasma eliminate the need for catalytic surface sites. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly two order of magnitude reduction in leakage current density for the smoother surfactant-assisted samples. Collectively, these data verify numerous predictions and calculations regarding the role of H-termination in regulating the habit of MgO crystals.

  2. Role of defects in BiFeO₃ multiferroic films and their local electronic structure by x-ray absorption spectroscopy

    SciTech Connect

    Ravalia, Ashish; Vagadia, Megha; Solanki, P. S.; Shah, N. A.; Kuberkar, D. G.; Gautam, S.; Chae, K. H.; Asokan, K.

    2014-10-21

    Present study reports the role of defects in the electrical transport in BiFeO₃ (BFO) multiferroic films and its local electronic structure investigated by near-edge X-ray absorption fine structure. Defects created by high energy 200 MeV Ag⁺¹⁵ ion irradiation with a fluence of ∼5 × 10¹¹ ions/cm² results in the increase in structural strain and reduction in the mobility of charge carriers and enhancement in resistive (I-V) and polarization (P-E) switching behaviour. At higher fluence of ∼5 × 10¹² ions/cm², there is a release in the structural strain due to local annealing effect, resulting in an increase in the mobility of charge carriers, which are released from oxygen vacancies and hence suppression in resistive and polarization switching. Near-edge X-ray absorption fine structure studies at Fe L₃,₂- and O K-edges show a significant change in the spectral features suggesting the modifications in the local electronic structure responsible for changes in the intrinsic magnetic moment and electrical transport properties of BFO.

  3. Residual stress and magnetic behavior of multiferroic CoFe{sub 2}O{sub 4}/Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} thin films

    SciTech Connect

    Sim, Chow Hong; Pan, Z. Z.; Wang, John

    2009-04-15

    Multiferroic composite thin films consisting of CoFe{sub 2}O{sub 4} (CFO) and Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) layers were deposited through a combined route of rf magnetron sputtering and sol gel on Pt(111)/TiO{sub 2}/SiO{sub 2}/Si substrates. The coupling effects in the bilayered thin film were studied by looking at the relationships among the crystallite orientation, magnetic behavior, and the in-plane residual stress. Phase selective residual stress analysis conducted by using x-ray method demonstrated a close correlation between the stress imposed on the PZT layer and its texture. A change in the PZT layer orientation from (111) to (010) with the increasing layer thickness was observed in the multiferroic thin film as the system changes from an interface energy minimizing texture to a strain energy density minimizing texture. The CFO phase in the multiferroic thin films was preferably oriented in the (111) orientation. However, there is a change in magnetization as well as coercivity of the multiferroic thin films when the top PZT layer was varied in thickness. A close correlation between the magnetization and the in-plane stress in the CFO bottom layer imposed by the PZT film thickness was observed.

  4. Structure and morphology of c-SiC films obtained by acetylene reaction with Si(111) surface

    NASA Astrophysics Data System (ADS)

    De Crescenzi, M.; Bernardini, R.; Gunnella, R.; Castrucci, P.

    2002-07-01

    In this work we investigated the structure and morphology of silicon carbide films grown under ultra-high-vacuum (UHV) conditions by acetylene (C 2H 2) carbonization of Si(111) surfaces kept at 650 °C. We used several UHV electron techniques to probe the local structural properties of the film and scanning tunneling microscopy (STM) to study its morphology. Our results indicated that C atoms occupy tetrahedral substitutional sites in the Si with a C-Si bond of 1.90±0.03 Å as in a bulk cubic SiC (c-SiC) crystal. X-ray diffraction data confirmed the formation of highly (111) oriented epitaxial crystallites characterized by the c-SiC lattice. STM images showed the formation of ordered, interconnected structures, rather flat at the atomic scale, triangular in shape, characterized by the same orientation and with an average area of 5000 nm 2 and an average height of 10-15 Å. Only a few holes can be detected which may be interpreted as empty spaces left by the patchwork growth of the silicon carbide triangular islands. Therefore, our growth procedure resulted to produce crystalline c-SiC films by using one of the most lowest temperature reported in literature.

  5. Synthesis of highly ordered mesoporous alumina thin films and their framework crystallization to γ-alumina phase.

    PubMed

    Jiang, Xiangfen; Oveisi, Hamid; Nemoto, Yoshihiro; Suzuki, Norihiro; Wu, Kevin C-W; Yamauchi, Yusuke

    2011-11-01

    Here we report the preparation of highly ordered mesoporous alumina films existing both as P6(3)/mmc and Fm-3m mesostructures by using triblock copolymer Pluronic P123 as the structure-directing agent. 2D grazing-incidence small-angle X-ray scattering (GI-SAXS) completely proves the existence of two different mesopore structures (i.e., [001]-oriented P6(3)/mmc and [111]-oriented Fm-3m symmetries). After calcination at 1000 °C, the amorphous alumina framework is successfully converted to γ-alumina crystals. During the crystallization process, large uniaxial shrinkage occurs along the direction perpendicular to the substrate with the retention of horizontal mesoscale periodicity, thereby resulting in formation of partially vertical mesoporosity in the film. Through detailed electron microscopic study, we discuss the formation mechanism for the vertical mesoporosity upon calcination. The obtained mesoporous γ-alumina film shows high thermal stability up to 1000 °C, which is highly useful in wide research areas such as catalyst supports and separators. PMID:21603720

  6. Effect of Argon/Oxygen Flow Rate Ratios on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films

    NASA Astrophysics Data System (ADS)

    Rani, D. Jhansi; Kumar, A. GuruSampath; Sarmash, T. Sofi; Chandra Babu Naidu, K.; Maddaiah, M.; Rao, T. Subba

    2016-06-01

    High transmitting, non absorbent, nano crystalline zirconium titanate (ZT) thin films suitable for anti reflection coatings (ARC) were deposited on to glass substrates by direct current (DC) magnetron reactive sputtering technique, under distinct Argon to Oxygen (Ar/O2) gas flow rate ratios of 31/1, 30/2, 29/3 and 28/4, with a net gas flow (Ar + O2) of 32sccm, at an optimum substrate temperature of 250°C. The influence of the gas mixture ratio on the film properties has been investigated by employing x-ray diffraction (XRD), ultra violet visible (UV-vis) spectroscopy, atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX) and four point probe methods. The films showed a predominant peak at 30.85° with (111) orientation. The crystallite size reduced from 22.94 nm to 13.5 nm and the surface roughness increased from 11.53 nm to 50.58 nm with increase in oxygen content respectively. The films deposited at 31/1 and 30/2 showed almost similar chemical composition. Increased oxygen content results an increase in electrical resistivity from 3.59 × 103 to 2.1 × 106 Ωm. The film deposited at Ar/O2 of 28/4 exhibited higher average optical transmittance of 91%, but its refractive index is higher than that of what is required for ARC. The films deposited at 31/1 and 30/2 of Ar/O2 possess higher transmittance (low absorbance) apart from suitable refractive index. Thus, these films are preferable candidates for ARC.

  7. Effect of Argon/Oxygen Flow Rate Ratios on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films

    NASA Astrophysics Data System (ADS)

    Rani, D. Jhansi; Kumar, A. GuruSampath; Sarmash, T. Sofi; Chandra Babu Naidu, K.; Maddaiah, M.; Rao, T. Subba

    2016-04-01

    High transmitting, non absorbent, nano crystalline zirconium titanate (ZT) thin films suitable for anti reflection coatings (ARC) were deposited on to glass substrates by direct current (DC) magnetron reactive sputtering technique, under distinct Argon to Oxygen (Ar/O2) gas flow rate ratios of 31/1, 30/2, 29/3 and 28/4, with a net gas flow (Ar + O2) of 32sccm, at an optimum substrate temperature of 250°C. The influence of the gas mixture ratio on the film properties has been investigated by employing x-ray diffraction (XRD), ultra violet visible (UV-vis) spectroscopy, atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX) and four point probe methods. The films showed a predominant peak at 30.85° with (111) orientation. The crystallite size reduced from 22.94 nm to 13.5 nm and the surface roughness increased from 11.53 nm to 50.58 nm with increase in oxygen content respectively. The films deposited at 31/1 and 30/2 showed almost similar chemical composition. Increased oxygen content results an increase in electrical resistivity from 3.59 × 103 to 2.1 × 106 Ωm. The film deposited at Ar/O2 of 28/4 exhibited higher average optical transmittance of 91%, but its refractive index is higher than that of what is required for ARC. The films deposited at 31/1 and 30/2 of Ar/O2 possess higher transmittance (low absorbance) apart from suitable refractive index. Thus, these films are preferable candidates for ARC.

  8. Grain boundary character distribution and texture evolution during surface energy-driven grain growth in nanocrystalline gold thin films

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shigeaki; Takagi, Hiroki; Watanabe, Tadao

    2013-04-01

    The evolution of grain boundary microstructure during annealing in sputtered gold thin films was investigated on the basis of FEG-SEM/EBSD/OIM analyses of nanocrystalline microstructure, in order to find a clue to the precise control of grain boundary microstructure for development of high performance polycrystalline thin films. Remarkably high fractions of coincidence site lattice (CSL) boundaries with specific Σ values such as Σ1, Σ3, Σ7, Σ13, Σ19 and Σ21 occurred in the gold thin film specimens on Pyrex glass substrate by annealing in air. The occurrence of higher fraction of these specific low-Σ boundaries is probably attributed to the evolution of a very sharp {111}-textures of different degrees which results from the preferential growth of {111}-oriented grains due to surface energy-driven grain growth. The fraction of low-Σ CSL boundaries increased with increasing area fraction of {111}-texture. The grain boundary character distribution in the gold thin film specimens was strongly affected by the annealing atmosphere and substrate materials. The sharpness of {111}-texture in the specimen annealed in low-vacuum was weaker than that in the specimen annealed in air, and an extraordinarily high fraction of Σ3 CSL boundaries occurred. The grain growth of gold thin film specimens on SiO2 glass substrate was much slower than that of specimens on Pyrex glass substrate. The fraction of low-Σ CSL boundaries observed for the gold thin film specimens on SiO2 glass substrate was lower than that in the specimens on Pyrex glass substrate. The inverse cubic root Σ dependence of low-Σ CSL boundaries in the gold thin film specimens was discussed in connection with the process of the evolution of grain boundary microstructure.

  9. Techniques for Achieving Zero Stress in Thin Films of Iridium, Chromium, and Nickel

    NASA Technical Reports Server (NTRS)

    Broadway, David M.; O'Dell, Stephen L.; Ramsey, Brian D.; Weimer, Jeffrey

    2015-01-01

    We examine techniques for achieving zero intrinsic stress in thin films of iridium, chromium, and nickel deposited by magnetron sputter deposition. The intrinsic stress is further correlated to the microstructural features and physical properties such as surface roughness and optical density at a scale appropriate to soft X-ray wavelengths. The examination of the stress in these materials is motivated by efforts to advance the optical performance of light-weight X-ray space telescopes into the regime of sub-arcsecond resolution through various deposition techniques that rely on control of the film stress to values within 10-100 MPa. A characteristic feature of the intrinsic stress behavior in chromium and nickel is their sensitivity to the magnitude and sign of the intrinsic stress with argon gas pressure and deposition rate, including the existence of a critical argon process pressure that results in zero film stress which scales linearly with the atomic mass of the sputtered species. While the effect of stress reversal with argon pressure has been previously reported by Hoffman and others for nickel and chromium, we report this effect for iridium. In addition to stress reversal, we identify zero stress in the optical functioning iridium layer shortly after island coalescence for low process pressures at a film thickness of approximately 35nm. The measurement of the low values of stress during deposition was achieved with the aid of a sensitive in-situ instrument capable of a minimum detectable level of stress, assuming a 35nm thick film, in the range of 0.40-6.0 MPa for <111> oriented crystalline silicon substrate thicknesses of 70-280 microns, respectively.

  10. Growth temperature effect on the structural and magnetic properties of Fe{sub 3}O{sub 4} films grown by the self-template method

    SciTech Connect

    Takahashi, R. Misumi, H.; Lippmaa, M.

    2014-07-21

    We have investigated the effect of growth temperature on the structure, surface morphology, and magnetic properties of Fe{sub 3}O{sub 4} thin films grown on SrTiO{sub 3}(001) substrates by a self-template method. To eliminate the intermixing of (001) and (111) orientations that usually occurs in spinel films grown on perovskite substrates, a thin self-template layer of (001)-oriented Fe{sub 3}O{sub 4} was deposited on a SrTiO{sub 3}(001) substrate at 400 °C prior to the main film growth at temperatures of up to 1100 °C. Increasing the growth temperature from 400 °C to 1100 °C resulted in greatly improved crystallinity of the Fe{sub 3}O{sub 4} thin films, with the rocking curve width dropping from 1.41° to 0.28°. Surface analysis by atomic force microscopy showed that raising the growth temperature increased the grain size and the surface roughness, ultimately leading to the formation of regular nanopyramid arrays at 1100 °C. The surface roughening and pyramid formation are caused by the dominance of the lowest surface energy spinel (111) crystal facet. The nanopyramids were fully relaxed but still perfectly (001)-oriented in the out-of-plane direction. The largest pyramids had the lowest coercivity due to a reduction of the demagnetization effect.

  11. Electrodeposited ZnS Precursor Layer with Improved Electrooptical Properties for Efficient Cu2ZnSnS4 Thin-Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Mkawi, E. M.; Ibrahim, K.; Ali, M. K. M.; Farrukh, M. A.; Mohamed, A. S.

    2015-10-01

    Zinc sulfide (ZnS) thin films were prepared on indium tin oxide-coated glass by electrodeposition using aqueous zinc sulfate, thiourea, and ammonia solutions at 80°C. The effects of sulfurization at temperatures of 350°C, 400°C, 450°C, and 500°C on the morphological, structural, optical, and electrical properties of the ZnS thin films were investigated. X-ray diffraction analysis showed that the ZnS thin films exhibited cubic zincblende structure with preferred (111) orientation. The film crystallization improved with increasing annealing temperature. Field-emission scanning electron microscopy images showed that the film morphology became more compact and uniform with increasing annealing temperature. The percentage of sulfur in the ZnS thin films increased after sulfurization until a stoichiometric S/Zn ratio was achieved at 500°C. The annealed films showed good adhesion to the glass substrates, with moderate transmittance (85%) in the visible region. Based on absorption measurements, the direct bandgap increased from 3.71 eV to 3.79 eV with annealing temperature, which is attributed to the change of the buffer material composition and suitable crystal surface properties for effective p- n junction formation. The ZnS thin films were used as a buffer layer in thin-film solar cells with the structure of soda-lime glass/Mo/Cu2ZnSnS4/ZnS/ZnO/Al grid. The best solar cell efficiency was 1.86%.

  12. Growth, microstructure and electrical properties of sputter-deposited hafnium oxide (HfO2) thin films grown using HfO2 ceramic target

    SciTech Connect

    Aguirre, B.; Vemuri, R. S.; Zubia, David; Engelhard, Mark H.; Shutthanandan, V.; Kamala Bharathi, K.; Ramana, Chintalapalle V.

    2011-01-01

    Hafnium oxide (HfO₂) thin films have been made by radio-frequency (rf) magnetron-sputtering onto Si(100) substrates under varying growth temperature (Ts). HfO₂ ceramic target has been employed for sputtering while varying the Ts from room temperature to 500⁰C during deposition. The effect of Ts on the growth and microstructure of deposited HfO₂ films has been studied using grazing incidence x-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and high-resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive x-ray spectrometry (EDS). The results indicate that the effect of Ts is significant on the growth, surface and interface structure, morphology and chemical composition of the HfO₂ films. Structural characterization indicates that the HfO₂ films grown at Ts<200 ⁰C are amorphous while films grown at Ts>200 ⁰C are nanocrystalline. An amorphous-to-crystalline transition occurs at Ts=200 ⁰C. Nanocrystalline HfO₂ films crystallized in a monoclinic structure with a (-111) orientation. XPS measurements indicated the high surface-chemical quality and stoichiometric nature of the grown HfO₂ films. An interface layer (IL) formation occurs due to reaction at the HfO₂-Si interface for HfO₂ films deposited at Ts>200 ⁰C. The thickness of IL increases with increasing Ts. XPS and EDS at the HfO₂-Si cross-section indicate the IL is a (Hf, Si)-O compound. The electrical characterization using capacitance-voltage measurements indicate that the dielectric constant decreases from 25 to 16 with increasing Ts.

  13. Cation non-stoichiometry in pulsed laser deposited Sr{sub 2+y}Fe{sub 1+x}Mo{sub 1-x}O₆ epitaxial films

    SciTech Connect

    Meyer, T. L.; Woodward, P. M.; Dixit, M.; Williams, R. E. A.; Susner, M. A.; Fraser, H. L.; McComb, D. W.; Sumption, M. D.; Lemberger, T. R.

    2014-07-07

    Sr₂FeMoO₆ (SFMO) films were grown on SrTiO₃ (100)- and (111)-oriented substrates via pulsed laser deposition (PLD). In order to study the fundamental characteristics of deposition, films were grown in two different PLD chambers. In chamber I, the best films were grown with a relatively long substrate-to-target distance (89 mm), high substrate temperature (850 °C), and low pressure (50 mTorr) in a 95% Ar/5% H₂ atmosphere. Although X-ray diffraction (XRD) measurements indicate these films are single phase, Rutherford Backscattering (RBS) measurements reveal considerable non-stoichiometry, corresponding to a Sr₂Fe{sub 1–x}Mo{sub 1+x}O₆ composition with x≅0.2–0.3. This level of non-stoichiometry results in inferior magnetic properties. In chamber II, the best films were grown with a much shorter substrate-to-target distance (38 mm), lower temperature (680 °C), and higher pressure (225 mTorr). XRD measurements show that the films are single phase, and RBS measurements indicate that they are nearly stoichiometric. The degree of ordering between Fe and Mo was dependent on both the temperature and pressure used during deposition, reaching a maximum order parameter of 85%. The saturation magnetization increases as the Fe/Mo ordering increases, reaching a maximum of 2.4 μB/f.u. Based on prior studies of bulk samples, one would expect a higher saturation magnetization for this degree of Fe/Mo order. The presence of extra strontium oxide layers in the form of Ruddlesden-Popper intergrowths appears to be responsible for the lower than expected saturation magnetization of these films.

  14. Influence of RF power on microstructural and electrochemical properties of rf-sputtered LiMn2O4 thin films

    NASA Astrophysics Data System (ADS)

    Jayanth-Babu, K.; Jeevan-Kumar, P.; Hussain, O. M.

    2013-06-01

    Thin films of Lithium transition metal oxides (LTMOs) have wide applications as a cathode material in the fabrication of all solid state thin film microbatteries. Among various LTMOs, LiMn2O4 with spinel structure is one of the most promising cathode material as it offers high energy density, high cell voltage, low cost and low toxicity. Hence in the present investigation thin films of LiMn2O4 were prepared by RF magnetron sputtering on gold coated silicon substrates maintained at a constant substrate temperature of 573 K with different RF powers ranging from 40 to 150 watts. The influence of RF power on micro structural and electrochemical properties of LiMn2O4 films was studied. The lattice parameter, Mn-Mn-O interatomic distance and grain size was found to be increased with the increase of RF power as evidenced from XRD and SEM studies. The films deposited at a moderate substrate temperature of 573 K with RF power 100 W exhibited predominant (111) orientation with cubic spinel structure. The calculated lattice parameter, Mn-Mn, Mn-O inter atomic distances for the films deposited at RF power 100 W was 8.215Å, 2.905 and 1.922 Å. From the electrochemical (EC) studies an initial discharge capacity of 38.5 μAhcm-2μm-1 was observed for the films deposited at RF power 100 W in the potential window of 0.0 - 1.2 V.

  15. A Novel Instrument and Methodology for the In-Situ Measurement of the Stress in Thin Films

    NASA Technical Reports Server (NTRS)

    Broadway, David M.; Omokanwaye, Mayowa O.; Ramsey, Brian D.

    2014-01-01

    We introduce a novel methodology for the in-situ measurement of mechanical stress during thin film growth utilizing a highly sensitive non-contact variation of the classic spherometer. By exploiting the known spherical deformation of the substrate the value of the stress induced curvature is inferred by measurement of only one point on the substrate's surface-the sagittal. From the known curvature the stress can be calculated using the well-known Stoney equation. Based on this methodology, a stress sensor has been designed which is simple, highly sensitive, compact, and low cost. As a result of its compact nature, the sensor can be mounted in any orientation to accommodate a given deposition geometry without the need for extensive modification to an already existing deposition system. The technique employs the use of a double side polished substrate that offers good specular reflectivity and is isotropic in its mechanical properties, such as <111> oriented crystalline silicon or amorphous soda lime glass, for example. The measurement of the displacement of the uncoated side during deposition is performed with a high resolution (i.e. 5nm), commercially available, inexpensive, fiber optic sensor which can be used in both high vacuum and high temperature environments (i.e. 10(exp-7) Torr and 480oC, respectively). A key attribute of this instrument lies in its potential to achieve sensitivity that rivals other measurement techniques such as the micro cantilever method but, due to the comparatively larger substrate area, offers a more robust and practical alternative for subsequent measurement of additional characteristics of the film that can might be correlated to film stress. We present measurement results of nickel films deposited by magnetron sputtering which show good qualitative agreement to the know behavior of polycrystalline films previously reported by Hoffman.

  16. Two-dimensional X-ray diffraction and transmission electron microscopy study on the effect of magnetron sputtering atmosphere on GaN/SiC interface and gallium nitride thin film crystal structure

    SciTech Connect

    Shen, Huaxiang; Zhu, Guo-Zhen; Botton, Gianluigi A.; Kitai, Adrian

    2015-03-21

    The growth mechanisms of high quality GaN thin films on 6H-SiC by sputtering were investigated by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The XRD θ-2θ scans show that high quality (0002) oriented GaN was deposited on 6H-SiC by reactive magnetron sputtering. Pole figures obtained by 2D-XRD clarify that GaN thin films are dominated by (0002) oriented wurtzite GaN and (111) oriented zinc-blende GaN. A thin amorphous silicon oxide layer on SiC surfaces observed by STEM plays a critical role in terms of the orientation information transfer from the substrate to the GaN epilayer. The addition of H{sub 2} into Ar and/or N{sub 2} during sputtering can reduce the thickness of the amorphous layer. Moreover, adding 5% H{sub 2} into Ar can facilitate a phase transformation from amorphous to crystalline in the silicon oxide layer and eliminate the unwanted (33{sup ¯}02) orientation in the GaN thin film. Fiber texture GaN thin films can be grown by adding 10% H{sub 2} into N{sub 2} due to the complex reaction between H{sub 2} and N{sub 2}.

  17. The magnetic and chemical structural property of the epitaxially-grown multilayered thin film

    NASA Astrophysics Data System (ADS)

    Lee, Hwachol

    L10 FePt- and Fe-related alloys such as FePtRh, FeRh and FeRhPd have been studied for the high magnetocrystalline anisotropy and magnetic phase transition property for the future application. In this work, the thin film structural and magnetic property is investigated for the selected FePtRh and FeRhPd alloys. The compositionally-modulated L10 FePtRh multilayered structure is grown epitaxially on a-plane Al2O3 with Cr and Pt buffer layer at 600degC growth temperature by DC sputtering technique and examined for the structural, interfacial and magnetic property. For the epitaxially grown L10 [Fe50Pt45Rh5 (FM) (10nm) / Fe50Pt25Rh25 (AFM) (20nm)]x8 superlattice, the magnetically and chemically sharp interface formation between layers was observed in X-ray diffraction, transmission electron microscopy and polarized neutron reflectivity measurements with the negligible exchange bias at room and a slight coupling effect at lower temperature regime. For FeRhPd, the magnetic phase transition of epitaxially-grown 111-oriented Fe46Rh48Pd6 thin film is studied. The applied Rhodium buffer layer on a-plane Al2O3 (11 20) at 600degC shows the extraordinarily high quality of epitaxial film in (111) orientation, where two broad and coherent peak in rocking curve, and Laue oscillations are observed. The epitaxially-grown Pd-doped FeRh on Pt (111) grown at 600degC, 700degC exhibits the co-existing stable L10 (111) and B2 (110) structures and magnetic phase transition around 300degC. On the other hand, the partially-ordered FeRhPd structure grown at 400degC, 500degC shows background high ferromagnetic state over 5K˜350K temperature. For the reduced thickness of Fe46Rh48Pd 6, the ferromagnetic state becomes dominant with a reduced portion of the film undergoing a magnetic phase transition. For some epitaxial FeRhPd film, the spin-glass-like disordered state is also observed in field dependent SQUID measurement. For the tri-layered FeRhPd with thin Pt spacer, the background

  18. Effect of Ba substitution on the multiferroic properties of BiFeO3 films on glass substrates

    NASA Astrophysics Data System (ADS)

    Chang, H. W.; Yuan, F. T.; Tu, K. T.; Lo, Y. C.; Tu, S. Y.; Wang, C. R.; Yang, A. B.; Tu, C. S.; Jen, S. U.; Chang, W. C.

    2015-05-01

    Effect of Ba substitution on the multiferroic properties of non-epitaxially grown polycrystalline Bi1-xBaxFeO3 (BBFO) films on refined Pt(111) electrode buffered glass substrates is studied. The structural analysis shows that a pure perovskite phase is present for BBFO films (x = 0.05-0.15), and (110) preferred orientation is developed for films with high x = 0.15. The grain size and surface roughness are reduced with increasing x. All studied BBFO films show desired ferroelectric and ferromagnetic properties. The good ferroelectric properties with the remanent polarization (2Pr) of 36-70 μC/cm2 and electrical coercive field (Ec) of 318-570 kV/cm are attained. On the other hand, the substitution of Ba2+ for Bi3+ in the A site of the BFO crystal structure can effectively enhance the ferromagnetic properties with magnetization (Ms) of 9.4-13.9 emu/cm3 and coercivity (Hc) of 1216-1380 Oe. The ferromagnetic and ferroelectric properties and leakage behavior as functions of Ba content x are discussed.

  19. Magnetic and structural characterization of high anisotropy cobalt-rich alloys: Thin films and patterns

    NASA Astrophysics Data System (ADS)

    Zana, Iulica

    In this dissertation the structural and magnetic characterization of high anisotropy Co-rich alloys for magnetic recording and MEMS applications has been carried out. The potential of Co78Sm22 as an ultra-high density recording medium was explored through comprehensive static and dynamic magnetic measurements. It was found out that hard magnetic properties (Hc = 4.5 kOe) can be achieved when CoSm is sputter-deposited on Cr80V 20 underlayer, comparable with those reported for state-of-the-art media at the end of 2002. Furthermore, the chemical stability and reliability of CoSm thin films was studied through combined accelerated aging and electrochemical methods. It was found out that CoSm thin films are more reactive than current recording media (CoPt), and a layer of Si3N4 of at least 6 nm provides satisfactory protection. Electrodeposition of Co80Pt20 onto highly textured Cu seed layer with either {100} or {111} orientation was studied. The influence of Cu texture and plating current density (cd) on the growth, morphology, microstructure, and magnetic properties of the CoPt films was investigated. Epitaxial CoPt thin films with uniform composition across the film thickness were deposited. The microstructure consists in fcc matrix and hcp matrix when plated on Cu(100) and Cu(111), respectively. CoPt hcp single phase films with c-axis normal to the substrate were grown on Cu(111) when plated at cd = 50 mA/cm2. As opposed to the films plated on Cu(100) which show a mostly in-plane magnetic anisotropy, the films plated on Cu(111) develop a well defined perpendicular magnetic anisotropy (PMA) due to the hcp phase with the c-axis normal to the substrate, which yields coercivities as high as 6.1 kOe. The origin of the high PMA was found to lie in the magnetocrystalline anisotropy. CoPt micromagnets have been successfully fabricated by the electrodeposition-through-mask method, which despite the small aspect ratio show a definite PMA. The PMA, together with the hard

  20. Film Boxes.

    ERIC Educational Resources Information Center

    Osterer, Irv

    2002-01-01

    Presents an art lesson in which students created three-dimensional designs for 35mm film packages to improve graphic arts learning. Describes how the students examined and created film boxes using QuarkXPress software. (CMK)

  1. Film Reviews

    ERIC Educational Resources Information Center

    Dowling, John, Ed.

    1976-01-01

    Reviews five instructional films on: P-N junctions; crystal diodes; nuclear fusion research; Schlieren photography; and the energy crisis; including discussions of solar, nuclear, and fossil fuel energy. Also lists numerous other available films. (MLH)

  2. Nanocomposite films

    DOEpatents

    Mitlin, David; , Ophus, Colin; Evoy, Stephane; Radmilovic, Velimir; Mohammadi, Reza; Westra, Ken; Nelson-Fitzpatrick, Nathaniel; Lee, Zonghoon

    2010-07-20

    A thin-film composition of nanocrystal molybdenum in an amorphous metallic matrix may be formed by co-sputtering Mo with aluminum or nickel. NEMS cantilevers may be formed from the film. The films exhibit high nanoindentation hardness and a reduction in roughness and intrinsic stress, while maintaining resistivity in the metallic range.

  3. On Film

    ERIC Educational Resources Information Center

    Watts, Marty

    2006-01-01

    In this article, the author discusses the role of window films in enhancing indoor air quality in schools. Historically, window film has been used to reduce temperatures in buildings prone to overheating. Too much solar energy entering through windows makes occupants uncomfortable and air conditioning more costly. Film has been a simple solution…

  4. Humanistic Films.

    ERIC Educational Resources Information Center

    Gaffney, Maureen, Ed.

    1981-01-01

    Designed for media specialists and educators, this issue includes seven articles focusing on humanistic films for children. Following a brief editorial encouraging the ideals of humanism, the first article presents an analysis of seven films with positive sex-role models. Included is a model for evaluating children's films. The second article…

  5. Red Shift of Faraday Rotation in Thin Films of Completely Bismuth-Substituted Iron Garnet Bi3Fe5O12

    NASA Astrophysics Data System (ADS)

    Chern, Ming-Yau; Lo, Fang-Yuh; Liu, Da-Ren; Yang, Kuang; Liaw, Juin-Sen

    1999-12-01

    The magnetooptical Faraday rotations of epitaxial films of BixY3-xFe5O12 (Bi:YIG) grown on [111]-oriented gadolinium gallium garnet (GGG) substrates by pulsed laser deposition (PLD) were studied with bismuth content x = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0. The Faraday rotation angles, θF, of the films were measured by the method of rotating analyzer ellipsometry (RAE) with the photon energy varied from 1.5 to 3.5 eV. It was shown that in addition to the increase of the Faraday rotation with increasing x, the peaks of θF shifted toward the red region as x changed from 1.0 to 1.5. The peak positions of θF for the completely Bi-substituted iron garnet, Bi3Fe5O12 (BIG), were found at 2.4 and 2.8 eV with peak values as large as -23 deg/µm and 44 deg/µm, respectively

  6. Transport Properties Of Fe{sub 3-x}Ti{sub x}O{sub 4}(x = 0.0 and 0.0206) Epitaxial Thin Films

    SciTech Connect

    Varshney, Dinesh; Yogi, Arvind; Verma, K.; Phase, D. M.

    2011-07-15

    Fe{sub 3-x}Ti{sub x}O{sub 4}(x = 0 and 0.0206) epitaxial thin films with thickness of 150 nm were prepared by pulsed-laser deposition technique on SrTiO{sub 3}(100), {alpha}-Al{sub 2}O{sub 3}(0001), Si (111) and Float Glass substrates. X-ray diffraction (XRD) pattern infers that parent and Ti doped magnetites are grown in single phase with (111) orientation. The Verwey transition temperature for Fe{sub 3}O{sub 4} thin films are 121 K (Float Glass), 123 K (SrTiO{sub 3}), 123.5 K ({alpha}-Al{sub 2}O{sub 3}) and 128 K (Si). It is shown that the Ti doping at B site results in the disappearance of Verwey transition in {l_brace}Ti{sub x}{sup 4+}Fe{sub 1-x}{sup 3+}Fe{sup 2+}{r_brace}O{sub 4}{sup 2-}.

  7. Potential variation around grain boundaries in BaSi{sub 2} films grown on multicrystalline silicon evaluated using Kelvin probe force microscopy

    SciTech Connect

    Baba, Masakazu; Tsukahara, Daichi; Toko, Kaoru; Hara, Kosuke O.; Usami, Noritaka; Sekiguchi, Takashi; Suemasu, Takashi

    2014-12-21

    Potential variations across the grain boundaries (GBs) in a 100 nm thick undoped n-BaSi{sub 2} film on a cast-grown multicrystalline Si (mc-Si) substrate are evaluated using Kelvin probe force microscopy (KFM). The θ-2θ X-ray diffraction pattern reveals diffraction peaks, such as (201), (301), (410), and (411) of BaSi{sub 2}. Local-area electron backscatter diffraction reveals that the a-axis of BaSi{sub 2} is tilted slightly from the surface normal, depending on the local crystal plane of the mc-Si. KFM measurements show that the potentials are not significantly disordered in the grown BaSi{sub 2}, even around the GBs of mc-Si. The potentials are higher at GBs of BaSi{sub 2} around Si GBs that are formed by grains with a Si(111) face and those with faces that deviate slightly from Si(111). Thus, downward band bending occurs at these BaSi{sub 2} GBs. Minority carriers (holes) undergo a repelling force near the GBs, which may suppress recombination as in the case of undoped n-BaSi{sub 2} epitaxial films on a single crystal Si(111) substrate. The barrier height for hole transport across the GBs varies in the range from 10 to 55 meV. The potentials are also higher at the BaSi{sub 2} GBs grown around Si GBs composed of grains with Si(001) and Si(111) faces. The barrier height for hole transport ranges from 5 to 55 meV. These results indicate that BaSi{sub 2} GBs formed on (111)-dominant Si surfaces do not have a negative influence on the minority-carrier properties, and thus BaSi{sub 2} formed on underlayers, such as (111)-oriented Si or Ge and on (111)-oriented mc-Si, can be utilized as a solar cell active layer.

  8. Fiber textures of titanium nitride and hafnium nitride thin films deposited by off-normal incidence magnetron sputtering

    SciTech Connect

    Deniz, D.; Harper, J. M. E.

    2008-09-15

    We studied the development of crystallographic texture in titanium nitride (TiN) and hafnium nitride (HfN) films deposited by off-normal incidence reactive magnetron sputtering at room temperature. Texture measurements were performed by x-ray pole figure analysis of the (111) and (200) diffraction peaks. For a deposition angle of 40 deg. from substrate normal, we obtained TiN biaxial textures for a range of deposition conditions using radio frequency (rf) sputtering. Typically, we find that the <111> orientation is close to the substrate normal and the <100> orientation is close to the direction of the deposition source, showing substantial in-plane alignment. We also introduced a 150 eV ion beam at 55 deg. with respect to substrate normal during rf sputtering of TiN. Ion beam enhancement caused TiN to align its out-of-plane texture along <100> orientation. In this case, (200) planes are slightly tilted with respect to the substrate normal away from the ion beam source, and (111) planes are tilted 50 deg. toward the ion beam source. For comparison, we found that HfN deposited at 40 deg. without ion bombardment has a strong <100> orientation parallel to the substrate normal. These results are consistent with momentum transfer among adatoms and ions followed by an increase in surface diffusion of the adatoms on (200) surfaces. The type of fiber texture results from a competition among texture mechanisms related to surface mobilities of adatoms, geometrical, and directional effects.

  9. Dependence of BiFeO3 thickness on exchange bias in BiFeO3/ Co2FeAl multiferroic structures

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Zhang, D. L.; Wang, Y. H.; Miao, J.; Xu, X. G.; Jiang, Y.

    2011-01-01

    We have grown BiFeO3 (BFO) thin films with different thickness on Si/SiO2/Ti/Pt(111) substrates by pulsed laser deposition. Half-metallic Co2FeAl (CFA) films with a thickness of 5 nm were then grown on the BFO films by magnetron sputtering. Through the magnetic hysteresis loops of the BFO/CFA heterostructure, we observe a direct correlation between the thickness of the BFO film and exchange bias (EB) field. The EB field exhibits fluctuation behavior with a cyclical BFO thickness of 60 nm, which is close to the spiral modulation wavelength (62 nm) of BFO. It indicates the influence of spiral modulation on the EB in the BFO/CFA multiferroic structure.

  10. Highly orientated growth and characterization of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films with different orientations on SrTiO{sub 3} substrates by chemical solution deposition method

    SciTech Connect

    Wenhao, Yin; Zhang, Yuanyuan Cao, Danyan; Yang, Jing; Bai, Wei; Duan, Chungang; Tang, Xiaodong; Chen, Ying; Wang, Genshui; Dong, Xianlin

    2015-05-07

    La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) thin films were successfully prepared on (100), (110), and (111) oriented SrTiO{sub 3} substrates by chemical solution deposition method. The structural, magnetic, and magnetotransport properties were systematically studied. X-ray diffraction θ-2θ and ϕ-scan measurements results show that all the films have perfect crystalline orientation and in-plane alignment. Both the Curie temperature and metal-insulator transition temperature are almost the same for all the three orientations, about 339 K. The magnetoresistance value (MR value, defined as (R{sub M} − R{sub 0})/R{sub 0} × 100%, where R{sub M} and R{sub 0} are the resistivity with and without applied magnetic field) for the films reaches maximum near the Curie temperature. Both the magnetization and MR value for (100) direction LSMO are the largest, and meanwhile for (111) direction are the smallest. The saturation magnetization decreases approximately proportional to T{sup 2} at low temperature (T < T{sub c}/2) for all the oriented film. Inversely, the resistivity increases proportional to T{sup 2} in the same temperature range, which can be attributed to the electron-electron scattering.

  11. (110)-Textured Ca-doped BiFeO3 film on refined Pt(111) electrode layer on glass substrate at reduced temperature

    NASA Astrophysics Data System (ADS)

    Chang, H. W.; Shen, C. Y.; Yuan, F. T.; Tien, S. H.; Lin, S. Y.; Chen, W. A.; Wang, C. R.; Tu, C. S.; Jen, S. U.

    2016-03-01

    Multiferroic and photovoltaic properties of polycrystalline Bi0.85Ca0.15FeO3 (BCFO) film on refined Pt(111) electrode buffered glass substrate have been studied. Optimized Pt(111) electrode layer having large grain size and smooth morphology enables the development of highly (110)-textured BCFO film at a temperature as low as 450 °C. The prepared BCFO film has dense microstructure, fine grain size, and smooth surface morphology. Good ferroelectric properties with the remanent polarization (2Pr) of 108 μC/cm2 and electrical coercive field of 405 kV/cm are achieved. Improved ferromagnetic properties with magnetization of 9.2 emu/cm3 and coercivity of 1250 Oe are also attained. Significant PV properties with open-circuit photovoltage of 0.49 V and the short-circuit photocurrent of 67.4 μA/cm2 at illumination intensity of 228 mW/cm2 are observed, which are comparable to BCFO ceramics or BFO epitaxial films.

  12. Film ispalators

    SciTech Connect

    Startsev, Aleksandr V; Stoilov, Yurii Yu

    2002-05-31

    New physical objects, ispalators based on free soap films, exhibit persistent flows of the soap solution in open and closed volumes in air with additions of gases of the C{sub 8}F{sub 18} type (p = 20 Torr) at temperature drops on the films of the order of tenths and hundredths of kelvin. The flows move continuously at a velocity of 5 - 20 cm s{sup -1}. It is found that the parts of an inclined ispalator film show anomalous behaviour upon heating: their weight increases and they move downward over the film, whereas the unheated parts of the film move upward. Continuous radial vortex flows accompanied by the formation and washing of the regions of a thin black film are observed on circular films in closed volumes upon their uniform external cooling by evaporating water for 5 - 10 hours. The rapid flows make film ispalators the efficient heat carriers, which operate at small temperature drops (tenths and hundredths of kelvin) and surpass copper in the amount of thermal energy being transferred. The outlook for the further study and applications of film ispalators for detecting thermal fields and laser radiation is discussed. (laser applications and other topics in quantum electronics)

  13. On the local electronic and atomic structure of Ce1-xPrxO2-δ epitaxial films on Si

    NASA Astrophysics Data System (ADS)

    Niu, Gang; Schubert, Markus Andreas; d'Acapito, Francesco; Zoellner, Marvin Hartwig; Schroeder, Thomas; Boscherini, Federico

    2014-09-01

    The local electronic and atomic structure of (111)-oriented, single crystalline mixed Ce1-xPrxO2-δ (x = 0, 0.1 and 0.6) epitaxial thin films on silicon substrates have been investigated in view of engineering redox properties of complex oxide films. Non-destructive X-ray absorption near edge structure reveals that Pr shows only +3 valence and Ce shows only nominal +4 valence in mixed oxides. Extended x-ray absorption fine structure (EXAFS) studies were performed at K edges of Ce and Pr using a specially designed monochromator system for high energy measurements. They demonstrate that the fluorite lattice of ceria (CeO2) is almost not perturbed for x = 0.1 sample, while higher Pr concentration (x = 0.6) not only generates a higher disorder level (thus more disordered oxygen) but also causes a significant reduction of Ce-O interatomic distances. The valence states of the cations were also examined by techniques operating in highly reducing environments: scanning transmission electron microscopy-electron energy loss spectroscopy and X-ray photoemission spectroscopy; in these reducing environments, evidence for the presence of Ce3+ was clearly found for the higher Pr concentration. Thus, the introduction of Pr3+ into CeO2 strongly enhances the oxygen exchange properties of CeO2. This improved oxygen mobility properties of CeO2 are attributed to the lattice disorder induced by Pr mixing in the CeO2 fluorite lattice, as demonstrated by EXAFS measurements. Thus, a comprehensive picture of the modifications of the atomic and electronic structure of Ce1-xPrxO2-δ epitaxial films and their relation is obtained.

  14. The role of strain and structure on oxygen ion conduction in nanoscale zirconia and ceria thin films

    NASA Astrophysics Data System (ADS)

    Jiang, Jun

    were decreased 3 - 7 times. YSZ thin films deposited on Al2O3 obtained a stable epitaxial growth along [110] (111)YSZ//[1010] (0001)Al2O3. By tailoring the thickness of YSZ thin film on Al2O3 from 100 nm to 6 nm, the lattice strain can be increased from nearly 1% to 2%. The corresponding conductivity increased by about 1 order of magnitude and the activation energy decreased from 0.99 eV to 0.79 eV. Ion cleaning of the MgO substrate surface was found to change the YSZ thin films' texture without large change to the conductivity, while ion cleaning of the Al2O3 substrate surface decreased the crystallinity without changing the texture and reduced the ionic conductivity of YSZ thin films by a factor of 4. Thus, crystallinity not texture was found to determine the ionic conductivity. In addition, a post annealing with a temperature as high as 1000 °C was able to increase the crystallinity of YSZ thin films therefore increasing the conductivity by a factor of 2. Gadolinia doped ceria (GDC) thin films deposited on MgO were randomly oriented along multi axes, suggesting a polycrystalline structure. While, on Al2O3, GDC thin films' growth became stable only oriented in (111) orientation, just like YSZ thin films on Al2O 3. In the thickness range of 15 nm - 173 nm, the maximum conductivity of GDC thin films was obtained at the thickness of 81 nm. Interestingly, as GDC thin films' thickness increased above 100 nm, the electrical properties changed from a bulk-like conduction to a grain boundary-like conduction.

  15. About Films.

    ERIC Educational Resources Information Center

    Christman, Robert; Krockover, Gerald H.

    1984-01-01

    Lists and briefly describes 46 college-level films. Films are arranged in the following categories: volcanism and earthquakes; plate tectonics; energy, water, and environmental concerns; petroleum and coal; astronomy; space exploration, space shuttle; paleontology; geomorphology; and mineralogy, petrology, and economic geology. (BC)

  16. Thin Films

    NASA Astrophysics Data System (ADS)

    Khorshidi, Zahra; Bahari, Ali; Gholipur, Reza

    2014-11-01

    Effect of annealing temperature on the characteristics of sol-gel-driven Ta ax La(1- a) x O y thin film spin-coated on Si substrate as a high- k gate dielectric was studied. Ta ax La(1- a) x O y thin films with different amounts of a were prepared (as-prepared samples). X-ray diffraction measurements of the as-prepared samples indicated that Ta0.3 x La0.7 x Oy film had an amorphous structure. Therefore, Ta0.3 x La0.7 x O y film was chosen to continue the present studies. The morphology of Ta0.3 x La0.7 x O y films was studied using scanning electron microscopy and atomic force microscopy techniques. The obtained results showed that the size of grain boundaries on Ta0.3 x La0.7 x O y film surfaces was increased with increasing annealing temperature. Electrical and optical characterizations of the as-prepared and annealed films were investigated as a function of annealing temperature using capacitance-voltage ( C- V) and current density-voltage ( J- V) measurements and the Tauc method. The obtained results demonstrated that Ta0.3 x La0.7 x O y films had high dielectric constant (≈27), wide band gap (≈4.5 eV), and low leakage current density (≈10-6 A/cm2 at 1 V).

  17. Thin Film?

    NASA Astrophysics Data System (ADS)

    Kariper, İ. Afşin

    2014-09-01

    This study focuses on the critical surface tension of lead sulfite (PbSO3) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO3 thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO3 thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.

  18. Film Language.

    ERIC Educational Resources Information Center

    Hudlin, Edward W.

    1979-01-01

    The author briefly surveys some of the claims made about the presumed nature of film as language and some of the problems that arise. He considers the views of two influential schools of film criticism: the Russian formalists (Pudovkin and Eisenstein) and the British semiologist (Peter Wollen). (Author/SJL)

  19. Film Makers On Film Making.

    ERIC Educational Resources Information Center

    Geduld, Harry M., Ed.

    This collection includes essays by and interviews with more than 30 film-makers, both classic and contemporary, on the subjects of their major interests and procedures in making films. The directors are: Louis Lumiere, Cecil Hepworth, Edwin S. Porter, Mack Sennett, David W. Griffith, Robert Flaherty, Charles Chaplin, Eric von Stroheim, Dziga…

  20. A comparative investigation on structure and multiferroic properties of bismuth ferrite thin films by multielement co-doping

    SciTech Connect

    Dong, Guohua; Tan, Guoqiang Luo, Yangyang; Liu, Wenlong; Xia, Ao; Ren, Huijun

    2014-12-15

    Highlights: • Multielement (Tb, Cr and Mn) co-doped BiFeO{sub 3} films were fabricated by CSD method. • Multielement co-doping induces a structural transition. • It is found effective to stabilize the valence of Fe ions at +3 by the strategy. • The co-doping at A/B-sites gives rise to the superior multiferroic properties. - Abstract: (Tb, Cr and Mn) multielement co-doped BiFeO{sub 3} (BTFCMO) thin films were prepared by the chemical solution deposition method on fluorine doped tin oxide (FTO) substrates. X-ray diffraction, Rietveld refinement and Raman analyses revealed that a phase transition from rhombohedral to triclinic structure occurs in the multielement co-doped BiFeO{sub 3} films. It is found that the doping is conducive to stabilizing the valence of Fe ions and reducing leakage current. In addition, the highly enhanced ferroelectric properties with a huge remanent polarization (2P{sub r}) of 239.6 μC/cm{sup 2} and a low coercive field (2E{sub c}) of 615.6 kV/cm are ascribed to the well film texture, the structure transition and the reduced leakage current by the co-doping. Moreover, the structure transition is the dominant factor resulting in the significant enhancement observed in magnetization (M{sub s} ∼ 10.5 emu/cm{sup 3}), owing to the collapse of the space-modulated spin structure. In this contribution, these results demonstrate that the multielement co-doping is in favor of the enhanced multiferroic properties of the BFO films for possible multifunctional applications.

  1. Thickness-dependent optical properties in compressively strained BiFeO{sub 3}/LaAlO{sub 3} films grown by pulsed laser deposition

    SciTech Connect

    Duan, Zhihua; Jiang, Kai; Wu, Jiada; Sun, Jian; Hu, Zhigao; Chu, Junhao

    2014-03-01

    Graphical abstract: - Highlights: • BFO with various thicknesses was grown on LAO substrates by pulsed laser deposition. • The structure and compressive strains were clarified via Raman scattering. • The charge transfer excitation was blue shifted with increasing compressive strain. • The compressive strain affects the distortion of Fe{sup 3+} local environment and O 2p states. - Abstract: Bismuth ferrite (BiFeO{sub 3}) films with various thicknesses were epitaxially grown on LaAlO{sub 3} substrates by pulsed laser deposition. The X-ray diffraction and Raman scattering spectra reveal that the films were highly (11{sup ¯}1) oriented with the single phase. With increasing the thickness, the compressive strain decreases and the strain ratios between the film and bulk crystal are evaluated to be 1.75, 1.57, and 1. Moreover, the compressive strain induces band gap shrinkage from 2.7 to 2.65 eV, while the charge transfer transition energy increases from 3.5 to 4.1 eV. It could be due to the shift of O 2p states and the variation of local Fe{sup 3+} crystal field.

  2. Piezoelectric Film.

    ERIC Educational Resources Information Center

    Garrison, Steve

    1992-01-01

    Presents activities that utilize piezoelectric film to familiarize students with fundamental principles of electricity. Describes classroom projects involving chemical sensors, microbalances, microphones, switches, infrared sensors, and power generation. (MDH)

  3. Film Reviews

    ERIC Educational Resources Information Center

    Ladd, George T.

    1974-01-01

    Briefly describes films about the following topics: water cycles, the energy crisis, the eruption of Mt. Aetna, the hot springs of Yellowstone National Park, and methods of using pine cones to determine the ages of ancient civilizations. (MLH)

  4. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  5. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  6. Mapping strain modulated electronic structure perturbations in mixed phase bismuth ferrite thin films

    SciTech Connect

    Krishnan, P.S. Sanakara R.; Aguiar, Jeffery A.; Ramasse, Q. M.; Kepaptsoglou, D. M.; Liang, W. I.; Chu, Y. H.; Browning, Nigel D.; Munroe, Paul R.; Nagarajan, Valanoor

    2015-01-01

    Strain engineering of epitaxial ferroelectrics has emerged as a powerful method to tailor the electromechanical response of these materials, although the effect of strain at the atomic scale and the interplay between lattice displacements and electronic structure changes are not yet fully understood. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we systematically probe the role of epitaxial strain in mixed phase bismuth ferrite thin films. Electron energy loss O K and Fe L2,3 edge spectra acquired across the rhombohedral (R)-tetragonal (T) phase boundary reveal progressive, and systematic changes, in electronic structure going from one phase to the other. The comparison of the acquired spectra, with theoretical simulations using DFT, suggests a breakage in the structural symmetry across the boundary due to the simultaneous presence of increasing epitaxial strain and off- axial symmetry in the T phase. This implies that the imposed epitaxial strain plays a significant role in not only changing the crystal-field geometry, but also the bonding environment surrounding the central iron cation at the interface thus providing new insights and a possible link to understand how the imposed strain could perturb magnetic ordering in the T phase BFO.

  7. Electric-field-controlled interface strain coupling and non-volatile resistance switching of La{sub 1-x}Ba{sub x}MnO₃ thin films epitaxially grown on relaxor-based ferroelectric single crystals

    SciTech Connect

    Zheng, Ming; Zhu, Qiu-Xiang; Li, Xue-Yan; Yang, Ming-Min; Li, Xiao-Min; Shi, Xun; Luo, Hao-Su; Zheng, Ren-Kui; Wang, Yu

    2014-09-21

    We have fabricated magnetoelectric heterostructures by growing ferromagnetic La{sub 1-x}Ba{sub x}MnO₃ (x=0.2, 0.4) thin films on (001)-, (110)-, and (111)-oriented 0.31Pb(In{sub 1/2}Nb{sub 1/2})O₃-0.35Pb(Mg{sub 1/3}Nb{sub 1/2})O₃-0.34PbTiO₃ (PINT) ferroelectric single-crystal substrates. Upon poling along the [001], [110], or [111] crystal direction, the electric-field-induced non-180° domain switching gives rise to a decrease in the resistance and an enhancement of the metal-to-insulator transition temperature TC of the films. By taking advantage of the 180° ferroelectric domain switching, we identify that such changes in the resistance and TC are caused by domain switching-induced strain but not domain switching-induced accumulation or depletion of charge carriers at the interface. Further, we found that the domain switching-induced strain effects can be efficiently controlled by a magnetic field, mediated by the electronic phase separation. Moreover, we determined the evolution of the strength of the electronic phase separation against temperature and magnetic field by recording the strain-tunability of the resistance [(ΔR/R){sub strain}] under magnetic fields. Additionally, opposing effects of domain switching-induced strain on ferromagnetism above and below 197 K for the La₀.₈Ba₀.₂MnO₃ film and 150 K for the La₀.₆Ba₀.₄MnO₃ film, respectively, were observed and explained by the magnetoelastic effect through adjusting the magnetic anisotropy. Finally, using the reversible ferroelastic domain switching of the PINT, we realized non-volatile resistance switching of the films at room temperature, implying potential applications of the magnetoelectric heterostructure in non-volatile memory devices.

  8. Electric-field-controlled interface strain coupling and non-volatile resistance switching of La1-xBaxMnO3 thin films epitaxially grown on relaxor-based ferroelectric single crystals

    NASA Astrophysics Data System (ADS)

    Zheng, Ming; Zhu, Qiu-Xiang; Li, Xue-Yan; Yang, Ming-Min; Wang, Yu; Li, Xiao-Min; Shi, Xun; Luo, Hao-Su; Zheng, Ren-Kui

    2014-09-01

    We have fabricated magnetoelectric heterostructures by growing ferromagnetic La1-xBaxMnO3 (x = 0.2, 0.4) thin films on (001)-, (110)-, and (111)-oriented 0.31Pb(In1/2Nb1/2)O3-0.35Pb(Mg1/3Nb1/2)O3-0.34PbTiO3 (PINT) ferroelectric single-crystal substrates. Upon poling along the [001], [110], or [111] crystal direction, the electric-field-induced non-180° domain switching gives rise to a decrease in the resistance and an enhancement of the metal-to-insulator transition temperature TC of the films. By taking advantage of the 180° ferroelectric domain switching, we identify that such changes in the resistance and TC are caused by domain switching-induced strain but not domain switching-induced accumulation or depletion of charge carriers at the interface. Further, we found that the domain switching-induced strain effects can be efficiently controlled by a magnetic field, mediated by the electronic phase separation. Moreover, we determined the evolution of the strength of the electronic phase separation against temperature and magnetic field by recording the strain-tunability of the resistance [(ΔR/R)strain] under magnetic fields. Additionally, opposing effects of domain switching-induced strain on ferromagnetism above and below 197 K for the La0.8Ba0.2MnO3 film and 150 K for the La0.6Ba0.4MnO3 film, respectively, were observed and explained by the magnetoelastic effect through adjusting the magnetic anisotropy. Finally, using the reversible ferroelastic domain switching of the PINT, we realized non-volatile resistance switching of the films at room temperature, implying potential applications of the magnetoelectric heterostructure in non-volatile memory devices.

  9. Film Credits

    ERIC Educational Resources Information Center

    Borja, Rhea R.

    2006-01-01

    With the advent of easy-to-use digital technology, schools are responding to the interests of their media-savvy students by offering more courses in filmmaking. In this article, the author features different films produced by students. Among other things, she discusses the students' growing interest in filmmaking.

  10. Thin Films

    NASA Astrophysics Data System (ADS)

    Naffouti, Wafa; Nasr, Tarek Ben; Mehdi, Ahmed; Kamoun-Turki, Najoua

    2014-11-01

    Titanium dioxide (TiO2) thin films were synthesized on glass substrates by spray pyrolysis. The effect of solution flow rate on the physical properties of the films was investigated by use of x-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy (AFM), and spectrophotometry techniques. XRD analysis revealed the tetragonal anatase phase of TiO2 with highly preferred (101) orientation. AFM images showed that grain size on top of TiO2 thin films depended on solution flow rate. An indirect band gap energy of 3.46 eV was determined by means of transmission and reflection measurements. The envelope method, based on the optical transmission spectrum, was used to determine film thickness and optical constants, for example real and imaginary parts of the dielectric constant, refractive index, and extinction coefficient. Ultraviolet and visible photoluminescence emission peaks were observed at room temperature. These peaks were attributed to the intrinsic emission and to the surface defect states, respectively.

  11. Black Films and Film-Makers.

    ERIC Educational Resources Information Center

    Patterson, Lindsay, Ed.

    The development of black films and the attitudes of the film industry toward black films and black actors are some of the topics examined in this anthology of essays. Section 1, "Nigger to Supernigger," contains such articles as "The Death of Rastus: Negroes in American Films" by Thomas R. Cripps and "Folk Values in a New Medium" by Alain Locke…

  12. Film and History.

    ERIC Educational Resources Information Center

    Schaber, Robin L.

    2002-01-01

    Provides an annotated bibliography of Web sites that focus on using film to teach history. Includes Web sites in five areas: (1) film and education; (2) history of cinema; (3) film and history resources; (4) film and women; and (5) film organizations. (CMK)

  13. Film: An Introduction.

    ERIC Educational Resources Information Center

    Fell, John L.

    "Understanding Film," the opening section of this book, discusses perceptions of and responses to film and the way in which experiences with and knowledge of other media affect film viewing. The second section, "Film Elements," analyzes the basic elements of film: the use of space and time, the impact of editing, sound and color, and the effects…

  14. On the local electronic and atomic structure of Ce1-xPrxO2-δ epitaxial films on Si

    SciTech Connect

    Niu, Gang Schubert, Markus Andreas; Zoellner, Marvin Hartwig; D'Acapito, Francesco; Boscherini, Federico

    2014-09-28

    The local electronic and atomic structure of (111)-oriented, single crystalline mixed Ce1-xPrxO2-δ (x = 0, 0.1 and 0.6) epitaxial thin films on silicon substrates have been investigated in view of engineering redox properties of complex oxide films. Non-destructive X-ray absorption near edge structure reveals that Pr shows only +3 valence and Ce shows only nominal +4 valence in mixed oxides. Extended x-ray absorption fine structure (EXAFS) studies were performed at K edges of Ce and Pr using a specially designed monochromator system for high energy measurements. They demonstrate that the fluorite lattice of ceria (CeO₂) is almost not perturbed for x = 0.1 sample, while higher Pr concentration (x = 0.6) not only generates a higher disorder level (thus more disordered oxygen) but also causes a significant reduction of Ce–O interatomic distances. The valence states of the cations were also examined by techniques operating in highly reducing environments: scanning transmission electron microscopy-electron energy loss spectroscopy and X-ray photoemission spectroscopy; in these reducing environments, evidence for the presence of Ce³⁺ was clearly found for the higher Pr concentration. Thus, the introduction of Pr³⁺ into CeO₂ strongly enhances the oxygen exchange properties of CeO₂. This improved oxygen mobility properties of CeO₂ are attributed to the lattice disorder induced by Pr mixing in the CeO₂ fluorite lattice, as demonstrated by EXAFS measurements. Thus, a comprehensive picture of the modifications of the atomic and electronic structure of Ce1-xPrxO2-δ epitaxial films and their relation is obtained.

  15. Ferroelectric ultrathin perovskite films

    DOEpatents

    Rappe, Andrew M; Kolpak, Alexie Michelle

    2013-12-10

    Disclosed herein are perovskite ferroelectric thin-film. Also disclosed are methods of controlling the properties of ferroelectric thin films. These films can be used in a variety materials and devices, such as catalysts and storage media, respectively.

  16. Investigation of NbNx thin films and nanoparticles grown by pulsed laser deposition and thermal diffusion

    NASA Astrophysics Data System (ADS)

    Hassan Farha, Ashraf

    Niobium nitride films (NbNx) were grown on Nb and Si (100) substrates using pulsed laser deposition (PLD), laser heating, and thermal diffusion methods. Niobium nitride films were deposited on Nb substrates using PLD with a Q-switched Nd: YAG laser (lambda = 1064 nm, 40 ns pulse width, and 10 Hz repetition rate) at different laser fluences, different nitrogen background pressures and deposition temperatures. The effect of changing PLD parameters for films done by PLD was studied. The seen observations establish guidelines for adjusting the laser parameters to achieve the desired morphology and phase of the grown NbNx films. When the fabrication parameters are fixed, except for laser fluence, surface roughness, deposition rate, nitrogen content, and grain size increases with increasing laser fluence. Increasing nitrogen background pressure leads to change in the phase structure of the NbNx films from mixed -Nb 2N and cubic delta-NbN phases to single hexagonal beta- Nb 2N. A change in substrate temperature led to a pronounced change in the preferred orientation of the crystal structure, the phase transformation, surface roughness, and composition of the films. The structural, electronic, and nanomechanical properties of niobium nitride PLD deposited at different nitrogen pressures (26.7-66.7 Pa) on Si(100) were investigated. The NbNx, films exhibited a cubic delta-NbN with a strong (111) orientation. A correlation between surface morphology, electronic, and superconducting properties was found. The highly-textured delta-NbN films have a Tc up to 15.07 K. The film was deposited at a nitrogen background pressure of 66.7 Pa exhibited improved superconducting properties and showed higher hardness values as compared to films deposited at lower nitrogen pressures. NbN nanoclusters that were deposited on carbon coated Cu-grids using PLD at laser fluence of 8 J/cm2 were observed. Niobium nitride is prepared by heating of Nb sample in a reactive nitrogen atmosphere (133 Pa

  17. Contemporary Films' Mini Course on Film Study.

    ERIC Educational Resources Information Center

    Schillaci, Peter

    This minicourse on film study can be a unit in English, in arts, or in the humanities. It can help to launch a film study course or complement an introduction to theater. Whatever form it takes, it helps to build a bridge to the student's media environment. Part one, the language of images, utilizes four films which demonstrate the basic elements…

  18. Magnetic and magnetotransport properties of Zn{sub x}Fe{sub 3−x}O{sub 4−y} thin films

    SciTech Connect

    Jedrecy, N. Hebert, C.; Perriere, J.; Nistor, M.; Millon, E.

    2014-12-07

    We present a detailed magnetic and magnetotransport investigation of spinel zinc ferrite Zn{sub x}Fe{sub 3−x}O{sub 4−y} (0.1 ≤ x ≤ 0.6) thin films grown by pulsed laser deposition on various substrates. The films are ranging from polycrystalline to (001)- or (111)-oriented. It is shown associating magnetic and resistivity measurements to x-ray and ion beam scattering analyses that the magnetic and electrical properties are tightly linked to the chemical composition and crystallinity/microstructure of the films, as they result from the choice of substrate and growth conditions. The use of oxidizing conditions (O{sub 2} pressure ≈ 10{sup −4}–10{sup −2} mbar) is highly detrimental to the crystalline quality and thus to the ferromagnetism. On the contrary, a partial O{sub 2} pressure of 3 × 10{sup −7} mbar combined to a growth temperature of 500 °C allows obtaining Zn{sub x}Fe{sub 3−x}O{sub 4−y} films displaying very good ferromagnetic features. The SiO{sub 2}/Si substrates, promoting (111) growth without interfacial effects, lead to better film properties than Al{sub 2}O{sub 3}(0001), MgO(001), or SrTiO{sub 3}(001) substrates: higher Curie temperatures and higher magnetization values (≈490 kAm{sup −1}) at room temperature. Above a Verwey-type critical temperature, a thermally activated spin polarized charge transport is observed, while in the low temperature range, the resistivity is well described by the variable range hopping model. However, the negative magnetoresistance response at low field remains modest and a monotonous decrease with increasing magnetic field is observed. We show that a steeper low field magnetoresistance decrease may be obtained in polycrystalline stoichiometric layers formed by a specific two-step growth process, which significantly reduces the density of grain/antiphase boundaries.

  19. Hierarchical templating of a BiFeO3-CoFe2O4 multiferroic nanocomposite by a triblock terpolymer film.

    PubMed

    Choi, Hong Kyoon; Aimon, Nicolas M; Kim, Dong Hun; Sun, Xue Yin; Gwyther, Jessica; Manners, Ian; Ross, Caroline A

    2014-09-23

    A process route to fabricate templated BiFeO3/CoFe2O4 (BFO/CFO) vertical nanocomposites is presented in which the self-assembly of the BFO/CFO is guided using a self-assembled triblock terpolymer. A linear triblock terpolymer was selected instead of a diblock copolymer in order to produce a square-symmetry template, which had a period of 44 nm. The triblock terpolymer pattern was transferred to a (001) Nb:SrTiO3 substrate to produce pits that formed preferential sites for the nucleation of CFO crystals, in contrast to the BFO, which wetted the flat regions of the substrate. The crystallographic orientation and magnetic properties of the templated BFO/CFO were characterized. PMID:25184546

  20. [Films: China and Japan].

    ERIC Educational Resources Information Center

    Gumport, Roberta H.

    The history of filmmaking in China and Japan and film usage in teaching are considered in this document. Pointing out how films describe historical context and culture, the document also describes various techniques of film making. Films in China were heavily influenced by western models and have tended to be tools of the power structure, as…

  1. Carbon thin film thermometry

    NASA Technical Reports Server (NTRS)

    Collier, R. S.; Sparks, L. L.; Strobridge, T. R.

    1973-01-01

    The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film.

  2. Hydrogen film cooling investigation

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Ewen, R. L.

    1973-01-01

    Effects of flow turning, flow acceleration, and supersonic flow on film cooling were determined experimentally and correlated in terms of an entrainment film cooling model. Experiments were conducted using thin walled metal test sections, hot nitrogen mainstream gas, and ambient hydrogen or nitrogen as film coolants. The entrainment film cooling model relates film cooling effectiveness to the amount of mainstream gases entrained with the film coolant in a mixing layer. The experimental apparatus and the analytical model used are described in detail and correlations for the entrainment fraction and film coolant-to-wall heat transfer coefficient are presented.

  3. Local origin of macroscopic properties and patterning in Lead zirconate titanate films

    NASA Astrophysics Data System (ADS)

    Bintachitt, Patamas

    This thesis describes the preparation of high quality lead zirconate titanate (PZT) films, the nonlinearity in their dielectric and piezoelectric responses, as well as their patterning by reactive ion etching. One goal of the research was to obtain {001} oriented PZT films on Pt-coated Si substrates. In this work, PbTiO3 buffer layers were chosen due to good lattice matching with PZT films, and the strong propensity for development of {001} orientation. The pyrolysis, crystallization steps, and lead excess addition of PbTiO3 buffer layers deposition were investigated. Using a thin PbTiO3 buffer layer and controlled pyrolysis conditions allowed {100} oriented PZT films to be prepared. The PbTiO3 buffer layer can be used over a full wafer to provide orientation. Higher piezoelectric coefficients, e31,f of -14 and -10 C/m2 were achieved for {001} PZT thin films of 1.0 mum and 0.24 mum thickness, respectively using appropriate poling conditions. The local and global domain wall contributions were studied by piezoelectric nonlinearity and dielectric nonlinearity in both {001}-textured PZT films and PZT films with mixed {001} and {111} orientation. It was found that films over the thickness range probed showed Rayleigh-like behavior. 4 mum thick films were nearly uniform in their Rayleigh coefficient, suggesting that any heterogeneities in the response developed at lateral length scales below the resolution of the PFM measurement. In contrast, thinner films showed significantly more patchiness in their response, so that fluctuations in behavior developed at a lateral length scale on the order of 0.6 to 2.5 micron. These variations did not appear to be correlated directly with the surface topology. Finally, it is hypothesized that the same population of domain wall contributes to the local and global nonlinearity. Nanoindentation measurements were conducted in an attempt to distinguish 180° and non-180° domain wall motion in these films. Non-180° domain walls can be

  4. Hydrothermal-assisted exfoliation of Y/Tb/Eu ternary layered rare-earth hydroxides into tens of micron-sized unilamellar nanosheets for highly oriented and color-tunable nano-phosphor films.

    PubMed

    Zhu, Qi; Xu, Zhixin; Li, Ji-Guang; Li, Xiaodong; Qi, Yang; Sun, Xudong

    2015-01-01

    Efficient exfoliation of well-crystallized (Y0.96Tb x Eu0.04-x )2(OH)5NO3 · nH2O (0 ≤ x ≤ 0.04) layered rare-earth hydroxide (LRH) crystals into tens of micron-sized unilamellar nanosheets has been successfully achieved by inserting water insoluble oleate anions (C17H33COO(-)) into the interlayer of the LRH via hydrothermal anion exchange at 120°C, followed by delaminating in toluene. The intercalation of oleate anions led to extremely expanded interlayer distances (up to approximately 5.2 nm) of the LRH crystals and accordingly disordered stacking of the ab planes along the c-axis and also weakened interlayer interactions, without significantly damaging the ab plane. As a consequence, the thickness of the LRH crystals increased from approximately 1 to 10 μm, exhibiting a behavior similar to that observed from the smectite clay in water. Highly [111]-oriented and approximately 100-nm thick oxide films of (Y0.96Tb x Eu0.04-x ) 2O3 (0 ≤ x ≤ 0.04) have been obtained through spin-coating of the exfoliated colloidal nanosheets on quartz substrate, followed by annealing at 800°C. Upon UV excitation at 266 nm, the oxide transparent films exhibit bright luminescence, with the color-tunable emission from red to orange, yellow, and then green by increasing the Tb(3+) content from x = 0 to 0.04. PMID:25852423

  5. Tens of micron-sized unilamellar nanosheets of Y/Eu layered rare-earth hydroxide: efficient exfoliation via fast anion exchange and their self-assembly into oriented oxide film with enhanced photoluminescence

    NASA Astrophysics Data System (ADS)

    Zhu, Qi; Li, Ji-Guang; Li, Xiaodong; Sun, Xudong; Qi, Yang; Zhu, Miaoyong; Sakka, Yoshio

    2014-02-01

    Layered rare-earth hydroxide (LRH) crystals of (Y0.95Eu0.05)2(OH)5NO3·nH2O with a lateral size of ˜ 300 μm and a thickness of ˜ 9 μm have been synthesized via a hydrothermal reaction of mixed nitrate solutions in the presence of mineralizer NH4NO3 at 200 °C for 24 h. LRH exhibits the ability to undergo intercalation and anion exchange with DS- (C12H25OSO3-) via hydrothermal treatment. Compared with traditional anion exchange at room temperature, hydrothermal processing not only shortens the anion exchange time from 720 to 24 h but also increases the basal spacing. The arrangements of DS- in the interlayer of LRH are significantly affected by the DS- concentration and reaction temperature, and the basal spacing of the LRH-DS sample in the crystal edge is assumed to be larger than that in the crystal center. A higher DS- concentration and reaction temperature both induce more intercalation of DS- anions into the interlayer gallery, thus yielding a larger basal spacing. Unilamellar nanosheets with a lateral size of ⩾60 μm and a thickness of ˜ 1.6 nm can be obtained by delaminating LRH-DS in formamide. The resultant unilamellar nanosheets are single crystalline. Transparent (Y0.95Eu0.05)2O3 phosphor films with a uniform [111] orientation and a layer thickness of ˜ 90 nm were constructed with the nanosheets as building blocks via spin-coating, followed by proper annealing. The oriented oxide film exhibits a strong red emission at 614 nm (the 5D0-7F2 transition of Eu3+), whose intensity is ˜ 2 times that of the powder form owing to the significant exposure of the (222) facets.

  6. Educational Films and the Historian

    ERIC Educational Resources Information Center

    Youngs, J. William T., Jr.

    1975-01-01

    Suggestions on how historians might use educational films more efficiently in the classroom are given. The range and diversity of educational films, educational film bibliography and criticism, and the classroom uses of films are discussed. (JR)

  7. Thin film metrology.

    PubMed

    Nitsch, Gerald; Flinn, Gregory

    2007-10-01

    Thin film metrology is suitable for characterising and performing quality control of a variety of coatings and films used in medical applications. The capabilities of today's systems are described. PMID:18078184

  8. Film as Film; Understanding and Judging Movies.

    ERIC Educational Resources Information Center

    Perkins, V. F.

    The criteria for judging movies which are presented here are based on the belief that film criticism becomes rational, if not "objective", when it displays and inspects the nature of its evidence and the bases of its arguments. The author dissents from the view of early film theorists that montage is the essence of cinema, and that cinema is to be…

  9. Exploring the Film.

    ERIC Educational Resources Information Center

    Kuhns, William; Stanley, Robert

    The purpose of film study is defined here in the words of D. W. Griffiths: "My goal is above all to make you see." This book is intended to be used as a text in a film study course. It traces the development of films from a scientific curiosity through silent films to modern wide screen productions. A comic strip is used to demonstrate the effect…

  10. Focus on Shakespearean Films.

    ERIC Educational Resources Information Center

    Eckert, Charles W., Ed.

    This is an anthology of reviews and critical pieces of the significant and available Shakespearean films made between 1935 and 1966. Included are three general essays on Shakespearean film by Ian Johnson, Henri Lemaitre, and Geoffrey Reeves. The specific films and their reviewers are: A Midsummer's Night Dream (1935) Allardyce Nicoll and Richard…

  11. Marine Science Film Catalogue.

    ERIC Educational Resources Information Center

    Chapman, Frank L.

    Forty-eight motion picture films and filmstrips in the field of marine science are catalogued in this booklet. Following the alphabetical index, one page is devoted to each film indicating its type, producer, recommended grade level, running time, and presence of color and/or sound. A summary of film content, possible uses, and outstanding…

  12. Thick Film Interference.

    ERIC Educational Resources Information Center

    Trefil, James

    1983-01-01

    Discusses why interference effects cannot be seen with a thick film, starting with a review of the origin of interference patterns in thin films. Considers properties of materials in films, properties of the light source, and the nature of light. (JN)

  13. TEACHING COMPOSITION WITH FILM.

    ERIC Educational Resources Information Center

    COURSEN, HERBERT R., JR.

    A COMPOSITION PROGRAM DESIGNED TO GIVE UPWARD BOUND STUDENTS A FEELING OF SUCCESS WAS BASED ON FILMS WHICH THE STUDENTS VIEWED, DISCUSSED, AND WROTE ABOUT. THE FILMS FELL ROUGHLY INTO THE CATEGORIES OF SOCIAL PROBLEMS, POLITICS AND PROPAGANDA, AND ART AND MUSIC. FOLLOWING CLASS DISCUSSIONS, STUDENTS WERE REQUIRED MERELY TO "WRITE ABOUT THE FILM."…

  14. Films for Special Education.

    ERIC Educational Resources Information Center

    Tringo, John L.

    Listed are approximately 500 films in the various areas of special education. The listing has been compiled from film company catalogs, social agency listings, and National Audiovisual Center listings. Information stated is that which was in the source materials (usually name, length, source, and brief description). Films are listed under the…

  15. 99 Films on Drugs.

    ERIC Educational Resources Information Center

    Weber, David O., Ed.

    This catalog describes and evaluates 16-millimeter films about various aspects of drug use. Among the subjects covered by the 99 films are the composition and effects of different drugs, reasons why people use drugs, life in the drug culture, the problem of law enforcement, and various means of dealing with drug users. Each film is synopsized. Two…

  16. The Sponsored Film.

    ERIC Educational Resources Information Center

    Klein, Walter J.

    For public relations professionals and would-be sponsors of films, this book provides guidelines for understanding the film medium and its potential as a persuasive force in industry, government, organizations, and religious orders. For filmmakers, it brings together practical information needed to survive in the sponsored-film industry and to…

  17. Health Careers Film Guide.

    ERIC Educational Resources Information Center

    National Institutes of Health (DHEW), Bethesda, MD. Bureau of Health Manpower Education.

    This document, which represents a survey of the entire health career film field, was designed to provide information for people interested in a health career. The guide indicates that a major criteria for film selection was recency; however, some older films that give a fairly accurate image of a profession were included, with some emphasis given…

  18. Particle film technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Particle Film Technology involves establishing a mineral particle film on the surface of a plant or plant product that: (1) is chemically inert, (2) has a mean particle diameter < 2 um, (3) is formulated to spread and create a uniform film, (4) does not physically disrupt gas exchange from the le...

  19. Getting into Film.

    ERIC Educational Resources Information Center

    London, Mel

    This book describes the various aspects of the film industry and the many jobs related to filmmaking, stressing that no "formula" exists for finding a successful career in the film industry. Chapters provide information on production, writing for film, cinematography, editing, music, sound, animation and graphics, acting and modeling, the "unsung…

  20. Metal versus rare-gas ion irradiation during Ti{sub 1-x}Al{sub x}N film growth by hybrid high power pulsed magnetron/dc magnetron co-sputtering using synchronized pulsed substrate bias

    SciTech Connect

    Greczynski, Grzegorz; Lu Jun; Jensen, Jens; Petrov, Ivan; Greene, Joseph E.; Bolz, Stephan; Koelker, Werner; Schiffers, Christoph; Lemmer, Oliver; Hultman, Lars

    2012-11-15

    Metastable NaCl-structure Ti{sub 1-x}Al{sub x}N is employed as a model system to probe the effects of metal versus rare-gas ion irradiation during film growth using reactive high-power pulsed magnetron sputtering (HIPIMS) of Al and dc magnetron sputtering of Ti. The alloy film composition is chosen to be x = 0.61, near the kinetic solubility limit at the growth temperature of 500 Degree-Sign C. Three sets of experiments are carried out: a -60 V substrate bias is applied either continuously, in synchronous with the full HIPIMS pulse, or in synchronous only with the metal-rich-plasma portion of the HIPIMS pulse. Alloy films grown under continuous dc bias exhibit a thickness-invariant small-grain, two-phase nanostructure (wurtzite AlN and cubic Ti{sub 1-x}Al{sub x}N) with random orientation, due primarily to intense Ar{sup +} irradiation leading to Ar incorporation (0.2 at. %), high compressive stress (-4.6 GPa), and material loss by resputtering. Synchronizing the bias with the full HIPIMS pulse results in films that exhibit much lower stress levels (-1.8 GPa) with no measureable Ar incorporation, larger grains elongated in the growth direction, a very small volume fraction of wurtzite AlN, and random orientation. By synchronizing the bias with the metal-plasma phase of the HIPIMS pulses, energetic Ar{sup +} ion bombardment is greatly reduced in favor of irradiation predominantly by Al{sup +} ions. The resulting films are single phase with a dense competitive columnar structure, strong 111 orientation, no measureable trapped Ar concentration, and even lower stress (-0.9 GPa). Thus, switching from Ar{sup +} to Al{sup +} bombardment, while maintaining the same integrated incident ion/metal ratio, eliminates phase separation, minimizes renucleation during growth, and reduces the high concentration of residual point defects, which give rise to compressive stress.

  1. Pyrolyzed thin film carbon

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  2. UV actinometer film

    NASA Technical Reports Server (NTRS)

    Coulbert, C. D.; Gupta, A.; Pitts, J.

    1980-01-01

    Cumulative UV radiation can be measured by low-cost polymer film that is unaffacted by visible light. Useful for virtually any surface, film can help paint and plastics manufacturers determine how well their products stand up against UV radiation. Actinometer film uses photochemically sensitive compound that changes its chemical composition in response to solar radiation. Extent of chemical conversion depends on length exposure and can be measured by examining film sample with spectrophotometer. Film can be exposed from several seconds up to month.

  3. Chronicles of foam films.

    PubMed

    Gochev, G; Platikanov, D; Miller, R

    2016-07-01

    The history of the scientific research on foam films, traditionally known as soap films, dates back to as early as the late 17th century when Boyle and Hooke paid special attention to the colours of soap bubbles. Their inspiration was transferred to Newton, who began systematic study of the science of foam films. Over the next centuries, a number of scientists dealt with the open questions of the drainage, stability and thickness of foam films. The significant contributions of Plateau and Gibbs in the middle/late 19th century are particularly recognized. After the "colours" method of Newton, Reinold and Rücker as well as Johhonnot developed optical methods for measuring the thickness of the thinner "non-colour" films (first order black) that are still in use today. At the beginning of the 20th century, various aspects of the foam film science were elucidated by the works of Dewar and Perrin and later by Mysels. Undoubtedly, the introduction of the disjoining pressure by Derjaguin and the manifestation of the DLVO theory in describing the film stability are considered as milestones in the theoretical development of foam films. The study of foam films gained momentum with the introduction of the microscopic foam film methodology by Scheludko and Exerowa, which is widely used today. This historical perspective serves as a guide through the chronological development of knowledge on foam films achieved over several centuries. PMID:26361708

  4. Depositing Diamondlike Carbon Films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Sovey, J. S.; Banks, B. A.

    1986-01-01

    New process demonstrated to make thin films (usually thousands of angstroms to few microns thick) that have properties of diamonds. Various plasma and ion-beam techniques employed to generate films. Films made by radio-frequency plasma decomposition of hydrocarbon gas or other alkanes, by low-energy carbon-ion-beam deposition, or by ion plating and dual ion technique using carbon target. Advantages of new process over others are films produced, though amorphous, are clear, extremely hard, chemically inert, of high resistivity, and have index of refraction of 3.2 properties similar to those of single-crystal diamonds. Films have possible uses in microelectronic applications, high-energy-laser and plastic windows, corrosion protection for metals, and other applications where desired properties of film shaped during the film-formation process.

  5. Ceramic Composite Thin Films

    NASA Technical Reports Server (NTRS)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  6. Documentary Elements in Early Films.

    ERIC Educational Resources Information Center

    Sanderson, Richard A.

    Focusing on documentary elements, this study examines the film content and film techniques of 681 motion pictures produced in the United States prior to 1904. Analysis of films by type, subject matter, and trends in subject matter shows that one-third of the early films are documentary in type and three-fourths of the films use subject matter of a…

  7. Coating of plasma polymerized film

    NASA Technical Reports Server (NTRS)

    Morita, S.; Ishibashi, S.

    1980-01-01

    Plasma polymerized thin film coating and the use of other coatings is suggested for passivation film, thin film used for conducting light, and solid body lubrication film of dielectrics of ultra insulators for electrical conduction, electron accessories, etc. The special features of flow discharge development and the polymerized film growth mechanism are discussed.

  8. Film Music. Factfile No. 8.

    ERIC Educational Resources Information Center

    Elsas, Diana, Ed.; And Others

    Organizations listed here with descriptive information include film music clubs and music guilds and associations. These are followed by a representative list of schools offering film music and/or film sound courses. Sources are listed for soundtrack recordings, sound effects/production music, films on film music, and oral history programs. The…

  9. Books on Film and Filmmaking.

    ERIC Educational Resources Information Center

    Ruth, Deborah D.

    This annotated bibliography of books on film and filmmaking contains references on materials related to animation production, general reference materials, student film production, film study, experimental film, critics and directors, sources of funds for filmmaking, local resources, periodicals for filmmaking classes, sources of free films, and…

  10. Evaporated VOx Thin Films

    NASA Astrophysics Data System (ADS)

    Stapinski, Tomasz; Leja, E.

    1989-03-01

    VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.

  11. Clinical careers film.

    PubMed

    2015-09-01

    Those interested in developing clinical academic careers might be interested in a short animated film by Health Education England (HEE) and the National Institute for Health Research. The three-minute film, a frame from which is shown below, describes the sort of opportunities that are on offer to all professionals as part of the HEE's clinical academic careers framework. You can view the film on YouTube at tinyurl.com/pelb95c. PMID:26309005

  12. Renaissance of the Film.

    ERIC Educational Resources Information Center

    Bellone, Julius, Ed.

    The post-World War II period was one of the liveliest in the history of the cinema. This is a collection of 33 critical articles on some of the best films of the perd. Most of the essays explicate the themes and symbols of the films. The essays deal with these films: "The Apu Trilogy,""L'Avventura,""Balthazar,""Blow-Up,""Bonnie and Clyde," Citizen…

  13. Protective overcoating of films

    NASA Technical Reports Server (NTRS)

    Maas, K. A.

    1972-01-01

    Kodak Film Type SO-212 was emulsion overcoated with gelatin and lacquer to evaluate the feasibility of application of the coatings, any image degradation, and the relative protection offered against abrasion. Evaluated were: Eastman motion picture film lacquer Type 485, water solutions of Eastman purified Calfskin gelatin, and experimental Eastman gelatin stripping film of 4 and 6 microns. Conclusions reached were: (1) All coatings can be applied with relative ease with the only limitation being that of equipment. (2) None of the coatings degrade the processed image. (3) All of the coatings provide protection to the emulsion. These conclusions apply to any film which may be considered for overcoating.

  14. Nanocarbonic transparent conductive films.

    PubMed

    Roth, Siegmar; Park, Hye Jin

    2010-07-01

    This tutorial review discusses the contradictory material properties of electrical conductivity and optical transparency for the examples of graphene films and carbon nanotube networks. It is argued that for homogeneous films both properties are linked by basic laws of physics and that for perfect monoatomic layers conductivity and transparency can be calculated from the fine structure constant. To beat these limitations, inhomogeneous films are required, such as graphene with an array of holes or nanotube networks. An overview is given on literature values of transparency and conductivity, both for graphene films and for nanotube networks. PMID:20502813

  15. Historical film processing

    NASA Astrophysics Data System (ADS)

    Wu, Yi; Suter, David

    1995-08-01

    This paper describes work using historical film material, including what is believed to be the world's first feature length film. The digital processing of historical film material permits many new facilities: digital restoration, electronic storage, automated indexing, and electronic delivery to name a few. Although the work aims ultimately to support all of the previously mentioned facilities, this paper concentrated upon automatic scene change detection, brightness correction, and frame registration. These processes are fundamental to a more complete and complex processing system, but, by themselves, could be immediately used in computer-assisted film cataloging.

  16. Engineering Nanoscale Multiferroic Composites for Memory Applications with Atomic Layer Deposition of Pb(ZrxTi1-x)O3 Thin Films

    NASA Astrophysics Data System (ADS)

    Chien, Diana

    This work focuses on the development of atomic layer deposition (ALD) for lead zirconate titanate, Pb(ZrxTi1-x)O 3 (PZT). Leveraging the surface-reaction controlled process based on alternating self-limiting surface reactions, PZT can be synthesized not only with elemental precision to realize the desired composition (Zr/Ti = 52/48) but also with outstanding conformality. The latter enables the integration of PZT with a ferromagnetic phase to realize multiferroism (MF) and magnetoelectric (ME) effect. Since PZT is one of the best known ferroelectric and piezoelectric materials due the large displacements of the Pb ions at the morphotropic phase boundary, PZT based MF composites could lead to stronger ME coupling through strain coupling at the interface. Specifically, ALD PZT thin films were synthesized by using beta-diketonate metalorganic precursors Pb(TMHD)2, Zr(TMHD)4, and Ti(O.i-Pr) 2(TMHD)2 and H2O. The number of local cycles and global cycles were regulated to achieve the desired stoichiometry and thickness, respectively. ALD of PZT was studied to obtain (100) textured PZT on Pt (111) oriented platinized silicon substrates. In order to attain a highly oriented PZT thin film, a (100) textured PbTiO3 seed layer was required because PZT orientation is governed by nucleation. MF nanocomposites were engineered using ALD PZT thin films to achieve controlled complex nanoscale structures, enabling porosity to be studied as a new additional parameter for nanocomposite architectures to enhance ME effect. Specifically, 3--6 nm-thick ALD PZT thin films were deposited to uniformly coat the walls of mesoporous cobalt ferrite (CFO) template. The PZT/CFO nanocomposites were electrically poled ex-situ and the change in magnetic moment was measured. The inverse magnetoelectric coupling coefficient, a, was determined to be 85.6 Oe-cm/mV. The in-plane results show no significant change in magnetization (1--4%) as a function of electric field, which was expected due to the effect

  17. The Possibility of Film Criticism.

    ERIC Educational Resources Information Center

    Poague, Leland; Cadbury, William

    1989-01-01

    Examines the role of critical language in film criticism. Compares and contrasts Monroe Beardsley's philosophy on film aesthetics with the New Criticism. Outlines some of the contributions Beardsley has made to the study of film criticism. (KM)

  18. Film-Makers' Cooperative Catalogue Number Six.

    ERIC Educational Resources Information Center

    Film-Makers' Cooperative, New York, NY.

    The Film-Makers' Cooperative services as a film depository and rental agency for any film-makers who may choose to make their work available to the general public. Approximately 1,600 films are listed in film-maker sequence. Excerpts of film reviews are provided for each entry. An index by film title and policies and procedures for film rental are…

  19. Microfilm--Which Film Type, Which Application?

    ERIC Educational Resources Information Center

    Dodson, Suzanne Cates

    1985-01-01

    Report on characteristics of different kinds of microfilm available indicates proper film for specific needs. Silver halide and nonsilver films, diazo film, vesicular film, reaction of films to light, effect of heat and humidity on films, film susceptibility to scratching, and potential longevity of film types are covered. (35 references) (EJS)

  20. Photocathode tunability: The photoemissive properties of ultra-thin multilayered MgO/Ag/MgO films synthesized by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Velazquez, Daniel Gomez

    Much of the early development of photocathode materials was aimed at the growth of photoemissive thin films with low work function, and high quantum efficiency (QE). It has been shown, both theoretically and experimentally, that metal-insulator junctions can lead to the modification of the work function and QE for coverages of a few monolayers of metal oxides on metallic substrates. However, the production of electron beams suitable for new photoinjector technologies often requires low emittance beams from the cathode itself. A theoretical model [Phys. Rev. Lett. 104, 046801 (2010)] based on a multilayered structure of MgO/Ag(001)/MgO with 4 monolayers of Ag(001) flanked by n monolayers (ML) of MgO indicates the possibility to reduce the surface work function and photoelectron beam emittance when the thickness n of the MgO layers is 2 or 3 monolayers. These predictions were tested experimentally. Synthesis of multilayered MgO/Ag/MgO films was performed using a custom-built pulsed laser deposition (PLD) system. In-situ growth monitoring was carried out by Reflection High-Energy Electron Diffraction (RHEED). Ex-situ techniques such as Scanning Tunneling Microscopy (STM), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (EDS) and Photoelectron Spectroscopy (PES) were used to show the formation of the crystalline and chemical structure. A custom-built Kelvin Probe/photocurrent-detector system was used to measure the work function and QE of the samples. Angle Resolved Photoelectron Spectroscopy was used to measure the angular photoelectron yield. Simultaneous reduction of work function and increase of QE was observed for (001) oriented multilayers of various thicknesses with respect to that of a bare Ag/MgO(001) surface. Work function measurements of multilayers of various thicknesses in the (111) orientation also showed a monotonic reduction with respect to that of a bare Ag/Si(111) surface. Angular emission was compared for a MgO/Ag/MgO multilayer

  1. Water depth penetration film test

    NASA Technical Reports Server (NTRS)

    Lockwood, H. E.; Perry, L.; Sauer, G. E.; Lamar, N. T.

    1974-01-01

    As part of the National Aeronautics and Space Administration Earth Resources Program, a comparative and controlled evaluation of nine film-filter combinations was completed to establish the relative effectiveness in recording water subsurface detail if exposed from an aerial platform over a typical water body. The films tested, with one exception, were those which prior was suggested had potential. These included an experimental 2-layer positive color film, a 2-layer (minus blue layer) film, a normal 3-layer color film, a panchromatic black-and-white film, and a black-and-white infrared film. Selective filtration was used with all films.

  2. Thin-film forces in pseudoemulsion films

    SciTech Connect

    Bergeron, V.; Radke, C.J. |

    1991-06-01

    Use of foam for enhanced oil recovery (EOR) has shown recent success in steam-flooding field applications. Foam can also provide an effective barrier against gas coning in thin oil zones. Both of these applications stem from the unique mobility-control properties a stable foam possesses when it exists in porous media. Unfortunately, oil has a major destabilizing effect on foam. Therefore, it is important for EOR applications to understand how oil destroys foam. Studies all indicate that stabilization of the pseudoemulsion film is critical to maintain foam stability in the presence of oil. Hence, to aid in design of surfactant formulations for foam insensitivity to oil the authors pursue direct measurement of the thin-film or disjoining forces that stabilize pseudoemulsion films. Experimental procedures and preliminary results are described.

  3. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  4. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, B.S.; Lauf, R.J.

    1995-09-19

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors. 8 figs.

  5. Authors on Film.

    ERIC Educational Resources Information Center

    Geduld, Harry M., Ed.

    Different authors' attitudes toward film are revealed through five different sections of this book: (1) articles, essays, and reviews pertaining to the silent cinema and the transition to sound; (2) general statements on the film medium or filmmakers and their messages; (3) essays dealing with the problems, involvements, and reflections of the…

  6. Construction of Meaning: Film.

    ERIC Educational Resources Information Center

    Pryluck, Calvin

    1995-01-01

    Notes that film has no clear set of rules, unlike all languages, which are deductive systems interpreted according to clear sets of rules. Suggests that film is an inductive system whose interpretation is based on a general understanding of events depicted as modified by production variables such as lighting, camera angles, and the context of…

  7. Stabilized chromium oxide film

    DOEpatents

    Nyaiesh, A.R.; Garwin, E.L.

    1986-08-04

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150A are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  8. Film Study Hang Ups.

    ERIC Educational Resources Information Center

    Grenier, Charles F.

    1969-01-01

    The interest and delight which students find in film should be preserved from a teacher's excessive zeal to analyze and explain. As the beauty of poetry is frequently diminished through exhaustive analyses of similes, rhyme schemes, and other technical devices, the value of film to high school students can be weakened through too great an emphasis…

  9. GPN Film Catalog 1972.

    ERIC Educational Resources Information Center

    Nebraska Univ., Lincoln. Great Plains National Instructional Television Library.

    The films described in this catalog were produced by schools or school-related organizations and were designed to meet the "relevant needs expressed by a broad spectrum of media personnel, students, and educators across the country." The catalog describes seventeen series and eight single films. For each of the series a description is presented…

  10. Elements of Film.

    ERIC Educational Resources Information Center

    Bobker, Lee R.

    A film is the successful combination of two distinct groups of elements: (1) the technical elements by which the film is made (camera, lighting, sound and editing) and (2) the esthetic elements that transform the craft into an art. This book attempts to combine the study of these elements by providing technical information about the process of…

  11. Creative Film-Making.

    ERIC Educational Resources Information Center

    Smallman, Kirk

    The fundamentals of motion picture photography are introduced with a physiological explanation for the illusion of motion in a film. Film stock formats and emulsions, camera features, and lights are listed and described. Various techniques of exposure control are illustrated in terms of their effects. Photographing action with a stationary or a…

  12. Film and the Humanities.

    ERIC Educational Resources Information Center

    O'Connor, John E., Ed.

    This report on a conference, which brought together representatives of various humanistic disciplines to explore the cross-disciplinary appeal of film study as well as the use of film in stimulating scholarship and teaching, includes a narrative summary of the day's conversations and issues raised, as well as of reprints of articles that suggest…

  13. Filming for Television.

    ERIC Educational Resources Information Center

    Englander, A. Arthur; Petzold, Paul

    Film makers, professional or amateur, will find in this volume an extensive discussion of the adaptation of film technique to television work, of the art of the camera operator, and of the productive relationships between people, organization, and hardware. Chapters include "The Beginnings," an overview of the interrelationship between roles in…

  14. Stabilized chromium oxide film

    DOEpatents

    Garwin, Edward L.; Nyaiesh, Ali R.

    1988-01-01

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  15. On Teaching Ethnographic Film

    ERIC Educational Resources Information Center

    Clarfield, Geoffrey

    2013-01-01

    The author of this article, a developmental anthropologist, illustrates how the instructor can use ethnographic films to enhance the study of anthropology and override notions about the scope and efficacy of Western intervention in the Third World, provided the instructor places such films in their proper historical and cultural context. He…

  16. Film Canister Science

    ERIC Educational Resources Information Center

    Ferstl, Andrew; Schneider, Jamie L.

    2007-01-01

    Opaque film canisters are readily available, cheap, and useful for scientific inquiry in the classroom. They can also be surprisingly versatile and useful as a tool for stimulating scientific inquiry. In this article, the authors describe inquiry activities using film canisters for preservice teachers, including a "black box" activity and several…

  17. Protolytic carbon film technology

    SciTech Connect

    Renschler, C.L.; White, C.A.

    1996-04-01

    This paper presents a technique for the deposition of polyacrylonitrile (PAN) on virtually any surface allowing carbon film formation with only the caveat that the substrate must withstand carbonization temperatures of at least 600 degrees centigrade. The influence of processing conditions upon the structure and properties of the carbonized film is discussed. Electrical conductivity, microstructure, and morphology control are also described.

  18. Critical Approaches to Film.

    ERIC Educational Resources Information Center

    Bywater, Timothy Robert

    This study deals primarily with recent academically oriented critical material, but it also embraces the range of film criticism that has been written for the mass audience in newspapers and periodicals. The study considers eight types of critical approaches to analyzing film: the journalistic approach, which contains both a reportorial-review and…

  19. Determining Film Art.

    ERIC Educational Resources Information Center

    Bullis, Roger

    1974-01-01

    The criteria by which films can and should be analyzed as art are discussed in this paper. A triangular model of theme-form-content is presented with form given greater significance than is usually the case in film criticism. The form-content-theme synthesis is the process in which theme is made clear by means of form and content within an…

  20. Films and Feelings.

    ERIC Educational Resources Information Center

    Gaffney, Maureen, Ed.

    1981-01-01

    Children's emotional responses to films are the focus of the four articles in this issue designed for media specialists and educators. Following an editorial discussing the responsibilities of media as put forth by Bruno Bettleheim, the first article presents a methodology and rationale for using story films to encourage children's exploration of…

  1. Discovery in Film.

    ERIC Educational Resources Information Center

    Heyer, Robert; Meyer, Anthony

    Seventy-eight "classic" short, non-feature films, cataloged according to six themes--communication, freedom, love, peace, happiness, and the underground--are discussed in this guide. The standard critique for each film has a fourfold purpose: (1) to indicate content and style; (2) to pose questions which provoke discussion; (3) to suggest resource…

  2. FAA Film Catalog.

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC.

    Some 75 films from the U.S. Department of Transportation's Federal Aviation Administration are listed in this catalog. Topics dealt with include aerodynamics, airports, aviation history and careers, flying clubs, navigation and weather. Most of the films are 16mm sound and color productions. Filmstrips requiring a 35mm projector and phonograph or…

  3. Dental Training Films.

    ERIC Educational Resources Information Center

    Veterans Administration Medical Center, Washington, DC.

    This dental training films catalog is organized into two sections. Section I is a category listing of the films by number and title, indexed according to generalized headings; categories are as follow: anatomy, articulator systems, complete dentures, dental assisting, dental laboratory technology, dental materials, dental office emergencies,…

  4. Film Making in Schools.

    ERIC Educational Resources Information Center

    Lowndes, Douglas

    A program which used practical film study to extend powers of observation and comment and to help young people (ages 12 through 16) develop an understanding of contemporary society is described in this manual. The role of film in school curricula and its integration with other studies is discussed in an opening section. The next section contains a…

  5. Abstract Film and Beyond.

    ERIC Educational Resources Information Center

    Le Grice, Malcolm

    A theoretical and historical account of the main preoccupations of makers of abstract films is presented in this book. The book's scope includes discussion of nonrepresentational forms as well as examination of experiments in the manipulation of time in films. The ten chapters discuss the following topics: art and cinematography, the first…

  6. Bursting of soap films

    NASA Astrophysics Data System (ADS)

    Chowdhury, Debashish; Stauffer, Dietrich

    1992-07-01

    Soap films consist of thin films of water in between two monolayers of amphiphilic molecules. Newton black films (NBFs) are the thinnest possible soap films. We have developed a microscopic model of NBFs; this model is a variant of the Widom model for microemulsions. By carrying out Monte Carlo simulations of this model, we have investigated the dependence of the lifetime of the NBFs on (a) the initial concentration of the amphiphilic molecules, (b) the temperature and (c) the bending rigidity of the constituent amphiphilic monolayers. We compare our results with the corresponding experimental observations and suggest further specific experiments. We establish that the “edge energy” of the model bilayer tends to stabilize the NBF; a similar mechanism leads to the well known phenomenon of “self-healing” of small enough holes in pierced vesicles. We also review the laws of growth of holes in soap films during rupture. Finally, we speculate on some other possible applications of our ideas.

  7. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T.

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  8. The National Film Registry: Acquiring Our Film Heritage.

    ERIC Educational Resources Information Center

    Ziegler, Roy A.

    The National Film Registry, which is primarily a designated list of films to be preserved by the Library of Congress, is also a valuable tool for selecting "films that are culturally, historically, and aesthetically significant." Following a brief discussion of the history and selection process of the National Film Registry, Southeast Missouri…

  9. Chiral atomically thin films

    NASA Astrophysics Data System (ADS)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm–1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  10. Chiral atomically thin films.

    PubMed

    Kim, Cheol-Joo; Sánchez-Castillo, A; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm(-1)) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra. PMID:26900756

  11. Film Scriptwriting: A Practical Manual.

    ERIC Educational Resources Information Center

    Swain, Dwight V.

    Dealing with both documentary and feature films, this book is a guide to using particular tools and procedures in developing ideas and concepts for writing film scripts. Part one deals with the factual, or documentary, film and discusses the proposal outline, film treatment, sequence outline, shooting script, and narration writing. Part two…

  12. Using Films in Literature Courses.

    ERIC Educational Resources Information Center

    Littell, Katherine M.

    1976-01-01

    Films are becoming recognized as an important medium of foreign language instruction. Although there is a lack of instructional films in German, an abundance of excellent feature films is available through the German Embassy and various consulates. Well-edited scenarios are needed, however, in order to make using these films an effective teaching…

  13. Diagnosing Disputes in Film Criticism.

    ERIC Educational Resources Information Center

    Schultz, Robert A.

    1979-01-01

    By classifying and analyzing actual disputes in film criticism, the author considers the following questions: Are there connections between film theory and film criticism? If so, which are healthy and which are diseased? If not, what alternative healthy function might film theory have? (Author/SJL)

  14. The Art of the Film.

    ERIC Educational Resources Information Center

    Lindgren, Ernest

    The author prefaces his consideration of films as an art form with a discussion of the mechanics of filmmaking. He describes the division of talent on a movie set, details the history of the tools of filmmakers, and explains the production and reproduction of a film. The influence of film techniques on plot development in a fiction film is…

  15. Discovery in Film, Book Two.

    ERIC Educational Resources Information Center

    Gordon, Malcolm W.

    Approximately 80 16 millimeter (16mm) short films are reviewed in this introduction and guide which attempts to be comprehensive in touching the major areas and styles of 16mm films now being produced. An attempt is made to describe as carefully as possible the style and content of each film and suggest ways in which the films might be used. Films…

  16. Negative birefringent polyimide films

    NASA Technical Reports Server (NTRS)

    Harris, Frank W. (Inventor); Cheng, Stephen Z. D. (Inventor)

    1994-01-01

    A negative birefringent film, useful in liquid crystal displays, and a method for controlling the negative birefringence of a polyimide film is disclosed which allows the matching of an application to a targeted amount of birefringence by controlling the degree of in-plane orientation of the polyimide by the selection of functional groups within both the diamine and dianhydride segments of the polyimide which affect the polyimide backbone chain rigidity, linearity, and symmetry. The higher the rigidity, linearity and symmetry of the polyimide backbone, the larger the value of the negative birefringence of the polyimide film.

  17. Thin film hydrogen sensor

    DOEpatents

    Cheng, Y.T.; Poli, A.A.; Meltser, M.A.

    1999-03-23

    A thin film hydrogen sensor includes a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end. 5 figs.

  18. Ultrahard carbon nanocomposite films

    SciTech Connect

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; PROVENCIO,PAULA P.; OVERMYER,DONALD L.; SIMPSON,REGINA L.; MARTINEZ-MIRANDA,L.J.

    2000-01-27

    Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.

  19. Biomimetic thin film synthesis

    SciTech Connect

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  20. Thin film hydrogen sensor

    DOEpatents

    Cheng, Yang-Tse; Poli, Andrea A.; Meltser, Mark Alexander

    1999-01-01

    A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.

  1. Amorphous diamond films

    DOEpatents

    Falabella, S.

    1998-06-09

    Amorphous diamond films having a significant reduction in intrinsic stress are prepared by biasing a substrate to be coated and depositing carbon ions thereon under controlled temperature conditions. 1 fig.

  2. Magnetron sputtered boron films

    DOEpatents

    Makowiecki, Daniel M.; Jankowski, Alan F.

    1998-01-01

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

  3. Magnetron sputtered boron films

    DOEpatents

    Makowiecki, D.M.; Jankowski, A.F.

    1998-06-16

    A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence. 8 figs.

  4. Nanostructured thermoplastic polyimide films

    SciTech Connect

    Aglan, Heshmat

    2015-05-19

    Structured films containing multi-walled carbon nanotubes ("MWCNTs") have enhanced mechanical performance in terms of strength, fracture resistance, and creep recovery of polyimide ("PI") films. Preferably, the loadings of MWCNTs can be in the range of 0.1 wt % to 0.5 wt %. The strength of the new PI films dried at 60.degree. C. increased by 55% and 72% for 0.1 wt % MWCNT and 0.5 wt % MWCNT loadings, respectively, while the fracture resistance increased by 23% for the 0.1 wt % MWCNTs and then decreases at a loading of 0.5 wt % MWCNTs. The films can be advantageously be created by managing a corresponding shift in the annealing temperature at which the maximum strength occurs as the MWCNT loadings increase.

  5. Quantitative film radiography

    SciTech Connect

    Devine, G.; Dobie, D.; Fugina, J.; Hernandez, J.; Logan, C.; Mohr, P.; Moss, R.; Schumacher, B.; Updike, E.; Weirup, D.

    1991-02-26

    We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernible by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudo-color images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. This report discusses: the method; film processor monitoring and control; verifying film and processor performance; and correction of scatter effects.

  6. TAMPERPROOF FILM BADGE

    DOEpatents

    Kocher, L.F.

    1958-10-01

    A persornel dosimeter film badge made of plastic, with provision for a picture of the wearer and an internal slide containing photographic film that is sensitive to various radiations, is described. Four windows made of differing material selectively attenuate alpha, beta, gamma rays, and neutrons so as to distinguish the particular type of radiation the wearer was subjected to. In addition, a lead shield has the identification number of the wearer perforated thereon so as to identify the film after processing. An internal magnetically actuated latch securely locks the slide within the body, and may be withdrawn only upon the external application of two strong magnetic forces in order to insure that the wearer or other curious persons will not accidentally expose the film to visual light.

  7. Sprites on Film

    NASA Video Gallery

    Filmed at 10,000 frames per second by Japan's NHK television, movies like this of electromagnetic bursts called "sprites" will help scientists better understand how weather high in the atmosphere r...

  8. Magnetoresistance of Au films

    SciTech Connect

    Zhang, D. L.; Song, X. H.; Zhang, X; Zhang, Xiaoguang

    2014-01-01

    Measurement of the magnetoresistance (MR) of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler s rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms.

  9. Polymer film composite transducer

    DOEpatents

    Owen, Thomas E.

    2005-09-20

    A composite piezoelectric transducer, whose piezoeletric element is a "ribbon wound" film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.

  10. Multifunctional thin film surface

    SciTech Connect

    Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

    2015-10-13

    A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

  11. Magnetoresistance of Au films

    DOE PAGESBeta

    Zhang, D. L.; Song, X. H.; Zhang, X.; Zhang, Xiaoguang

    2014-12-10

    Measurement of the magnetoresistance (MR) of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler s rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms.

  12. Thin film tritium dosimetry

    DOEpatents

    Moran, Paul R.

    1976-01-01

    The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

  13. Tunable photoelectrochemical performance of Au/BiFeO3 heterostructure.

    PubMed

    Huang, Yen-Lin; Chang, Wei Sea; Van, Chien Nguyen; Liu, Heng-Jui; Tsai, Kai-An; Chen, Jhih-Wei; Kuo, Ho-Hung; Tzeng, Wen-Yen; Chen, Yi-Chun; Wu, Chung-Lin; Luo, Chih-Wei; Hsu, Yung-Jung; Chu, Ying-Hao

    2016-08-25

    Ferroelectric photoelectrodes, other than conventional semiconductors, are alternative photo-absorbers in the process of water splitting. However, the capture of photons and efficient transfer of photo-excited carriers remain as two critical issues in ferroelectric photoelectrodes. In this work, we overcome the aforementioned issues by decorating the ferroelectric BiFeO3 (BFO) surface with Au nanocrystals, and thus improving the photoelectrochemical (PEC) performance of BFO film. We demonstrate that the internal field induced by the spontaneous polarization of BFO can (1) tune the efficiency of the photo-excited carriers' separation and charge transfer characteristics in bare BFO photoelectrodes, and (2) modulate an extra optical absorption within the visible light region, created by the surface plasmon resonance excitation of Au nanocrystals to capture more photons in the Au/BFO heterostructure. This study provides key insights for understanding the tunable features of PEC performance, composed of the heterostructure of noble metals and ferroelectric materials. PMID:27533610

  14. Preparation of a heteroepitaxial LaxSryMnzO3/BiFeO3 bilayer by r.f. magnetron sputtering with various oxygen gas flow ratios

    NASA Astrophysics Data System (ADS)

    Naganuma, H.; Ichinose, T.; Begum, H. A.; Sato, S.; Han, X. F.; Miyazaki, T.; Bae, In-T.; Oogane, M.; Ando, Y.

    2014-08-01

    BiFeO3 (BFO) and LaxSryMnzO3 (LSMO) films were epitaxially grown on SrTiO3 (100) substrates by r.f. magnetron sputtering with various oxygen gas flow ratios (FO2). Compositional ratios of each atom in both of BFO and LSMO could be controlled kept to around 10 at.% by changing FO2. Adjusting the compositional ratio to La0.35Sr0.15Mn0.5O3 not only increase Tc of LSMO but also produces sufficient oxygen to form a perovskite lattice. For an LSMO/BFO heterostructure, detailed observation by cross sectional transmission electron microscopy (TEM) revealed that the lattice of rhombohedral (SG: R-3c) LSMO was shrank by a clamping effect from the SrTiO3 substrates, and then the BFO was grown in two layers: (i) an interfacial BFO layer (7 nm thick) with evenly shrunk a-axis and c-axis, and (ii) an upper BFO layer (25 nm thick) expanded along the c-axis. Neither misfit strain nor dislocations appeared at the interface between the shrunken BFO and LSMO layers, and these heterostructures did not show exchange bias. These results suggest that BFO is suitable for a tunneling barrier combine with LSMO electrode.

  15. Tunable electronic and magnetism of SrTiO3/BiFeO3 (001) superlattice: For electrochemical applications

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Sopiha, Kostiantyn; Sobhan, Mushtaq; Anariba, Franklin; Ong, Khuong Phuong; Zheng, Jian Wei; Wu, Ping

    2016-01-01

    Practical strategy in tuning the conductivity and magnetism of SrTiO3/BiFeO3 (STO/BFO) (001) superlattice is investigated using the first-principles method based on density functional theory. Our calculated results show that both the conductivity and magnetism of this superlattice can be tuned via a control of its interface terminations. The STO layers maintain semiconducting, while the BFO layers demonstrate metallic character. Therefore, the conductivity of STO/BFO is controlled by the BFO layers. Furthermore, a magnetic STO/BFO (001) superlattice can be found in n-type TiO2/BiO interface but with heavy electron carriers. The thickness of BFO does not change the electronic structure and character of STO/BFO (001) superlattice. This study provides a fundamental understanding of the chemically turned conductivity and magnetism of BFO thin films, which may further advance electrochemical applications like magnetic-field aided chemical gas sensing, solar cells, and photo-catalytic chemical reactions.

  16. Films and Film Sources for Materials Science and Engineering Courses

    ERIC Educational Resources Information Center

    Evans, Edward B.

    1972-01-01

    A selected list of films that are suitable for secondary schools through universities. They cover all phases of materials science and engineering. The films may be obtained, usually free of charge, for listed sources. (DF)

  17. Epitaxial thin films

    DOEpatents

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  18. Thin film scintillators

    NASA Astrophysics Data System (ADS)

    McDonald, Warren; McKinney, George; Tzolov, Marian

    2015-03-01

    Scintillating materials convert energy flux (particles or electromagnetic waves) into light with spectral characteristic matching a subsequent light detector. Commercial scintillators such as yttrium aluminum garnet (YAG) and yttrium aluminum perovskite (YAP) are commonly used. These are inefficient at lower energies due to the conductive coating present on their top surface, which is needed to avoid charging. We hypothesize that nano-structured thin film scintillators will outperform the commercial scintillators at low electron energies. We have developed alternative thin film scintillators, zinc tungstate and zinc oxide, which show promise for higher sensitivity to lower energy electrons since they are inherently conductive. Zinc tungstate films exhibit photoluminescence quantum efficiency of 74%. Cathodoluminescence spectroscopy was applied in transmission and reflection geometries. The comparison between the thin films and the YAG and YAP commercial scintillators shows much higher light output from the zinc tungstate and zinc oxide at electron energies less than 5 keV. Our films were integrated in a backscattered electron detector. This detector delivers better images than an identical detector with commercial YAG scintillator at low electron energies. Dr. Nicholas Barbi from PulseTor LLC, Dr. Anura Goonewardene, NSF Grants: #0806660, #1058829, #0923047.

  19. Sensitometric properties of radiographic films and film classification

    NASA Astrophysics Data System (ADS)

    Siidorow, A.

    An attempt was made to elucidate those film characteristics which affect the radiographic image quality and which could be used as the basis of film classification. A literary survey showed that it is apparently impossible to measure the most important film characteristics, i.e., graininess and granularity, in a reliable and simple way. An existing classification method based on a visual comparison of film graininess is recommended.

  20. From Written Film History to Visual Film History.

    ERIC Educational Resources Information Center

    Petric, Vladimir

    The poor quality of most university courses in film history is due to several factors, among them the fact that there is insufficient analytical documentation and direct cinematic illustration in existent written film histories. These histories examine films on a thematic level, offering noncinematic interpretation such as literary meaning, social…

  1. Depositing Adherent Ag Films On Ti Films On Alumina

    NASA Technical Reports Server (NTRS)

    Honecy, Frank S.

    1995-01-01

    Report discusses cleaning of ceramic (principally, alumina) substrates in preparation for sputter deposition of titanium intermediate films on substrates followed by sputter deposition of outer silver films. Principal intended application, substrates sliding parts in advanced high-temperature heat engines, and outer silver films serve as solid lubricants: lubricating properties described in "Solid Lubricant for Alumina" (LEW-15495).

  2. The New Film Technologies: Computerized Video-Assisted Film Production.

    ERIC Educational Resources Information Center

    Mott, Donald R.

    Over the past few years, video technology has been used to assist film directors after they have shot a scene, to control costs, and to create special effects, especially computer assisted graphics. At present, a computer based editing system called "Film 5" combines computer technology and video tape with film to save as much as 50% of the cost…

  3. A multilayer sonic film

    NASA Astrophysics Data System (ADS)

    Munteanu, L.; Chiroiu, V.; Sireteanu, T.; Dumitriu, D.

    2015-10-01

    A non-periodic multilayer film was analyzed to show that, despite its non-periodicity, the film exhibits full band-gaps and localized modes at its interfaces, as well as in the sonic composites. The film consists of alternating layers of two different materials that follow a triadic Cantor sequence. The Cantor structure shows extremely low thresholds for subharmonic generation of ultrasonic waves, compared with homogeneous and periodic structures. The coupling between the extended-mode (phonon) and the localized-mode (fracton) vibration regimes explains the generation of full band-gaps, for which there are no propagating Lamb waves. The large enhancement of the nonlinear interaction results from a more favorable frequency and spatial matching of coupled modes. A full band-gap that excludes Love waves is also analyzed.

  4. Thin film temperature sensor

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Przybyszewski, J. S.

    1980-01-01

    Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

  5. Photographic film image enhancement

    NASA Technical Reports Server (NTRS)

    Horner, J. L.

    1975-01-01

    A series of experiments were undertaken to assess the feasibility of defogging color film by the techniques of optical spatial filtering. A coherent optical processor was built using red, blue, and green laser light input and specially designed Fourier transformation lenses. An array of spatial filters was fabricated on black and white emulsion slides using the coherent optical processor. The technique was first applied to laboratory white light fogged film, and the results were successful. However, when the same technique was applied to some original Apollo X radiation fogged color negatives, the results showed no similar restoration. Examples of each experiment are presented and possible reasons for the lack of restoration in the Apollo films are discussed.

  6. Thin film photovoltaics

    SciTech Connect

    Zweibel, K; Ullal, H S

    1989-05-01

    Thin films are considered a potentially attractive technological approach to making cost-effective electricity by photovoltaics. Over the last twenty years, many have been investigated and some (cadmium telluride, copper indium diselenide, amorphous silicon) have become leading candidates for future large-scale commercialization. This paper surveys the past development of these key thin films and gives their status and future prospects. In all cases, significant progress toward cost-effective PV electricity has been made. If this progress continues, it appears that thin film PV could provide electricity that is competitive for summer daytime peaking power requirements by the middle of the 1990s; and electricity in a range that is competitive with fossil fuel costs (i.e., 6 cents/kilowatt-hour) should be available from PV around the turn of the century. 22 refs., 9 figs.

  7. Thin films and uses

    DOEpatents

    Baskaran, Suresh; Graff, Gordon L.; Song, Lin

    1998-01-01

    The invention provides a method for synthesizing a titanium oxide-containing film comprising the following steps: (a) preparing an aqueous solution of a titanium chelate with a titanium molarity in the range of 0.01M to 0.6M. (b) immersing a substrate in the prepared solution, (c) decomposing the titanium chelate to deposit a film on the substrate. The titanium chelate maybe decomposed acid, base, temperature or other means. A preferred method provides for the deposit of adherent titanium oxide films from C2 to C5 hydroxy carboxylic acids. In another aspect the invention is a novel article of manufacture having a titanium coating which protects the substrate against ultraviolet damage. In another aspect the invention provides novel semipermeable gas separation membranes, and a method for producing them.

  8. Foundation for Film and Science

    ERIC Educational Resources Information Center

    van der Veen, G.

    1976-01-01

    Provides a comprehensive discussion on the Stichting Film en Wetenschap, SFW (Foundation for Film and Science), in Utrecht. Various aspects of the use of audio-visual aids in university teaching are looked at in detail. (Editor/RK)

  9. Thin films for material engineering

    NASA Astrophysics Data System (ADS)

    Wasa, Kiyotaka

    2016-07-01

    Thin films are defined as two-dimensional materials formed by condensing one by one atomic/molecular/ionic species of matter in contrast to bulk three-dimensional sintered ceramics. They are grown through atomic collisional chemical reaction on a substrate surface. Thin film growth processes are fascinating for developing innovative exotic materials. On the basis of my long research on sputtering deposition, this paper firstly describes the kinetic energy effect of sputtered adatoms on thin film growth and discusses on a possibility of room-temperature growth of cubic diamond crystallites and the perovskite thin films of binary compound PbTiO3. Secondly, high-performance sputtered ferroelectric thin films with extraordinary excellent crystallinity compatible with MBE deposited thin films are described in relation to a possible application for thin-film MEMS. Finally, the present thin-film technologies are discussed in terms of a future material science and engineering.

  10. The Nuclear Debate in Film

    ERIC Educational Resources Information Center

    Dowling, John

    1977-01-01

    Provides a nuclear film bibliography grouped into the areas of: building and using the bomb; living with the bomb; and living with nuclear power. These films are for mature high school students and older. (MLH)

  11. Thin film solar cell workshop

    NASA Technical Reports Server (NTRS)

    Armstrong, Joe; Jeffrey, Frank

    1993-01-01

    A summation of responses to questions posed to the thin-film solar cell workshop and the ensuing discussion is provided. Participants in the workshop included photovoltaic manufacturers (both thin film and crystalline), cell performance investigators, and consumers.

  12. Thin film ceramic thermocouples

    NASA Technical Reports Server (NTRS)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  13. Thin film photovoltaic device

    DOEpatents

    Catalano, Anthony W.; Bhushan, Manjul

    1982-01-01

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

  14. Sepis education on film.

    PubMed

    2016-09-01

    Early identification and management is vital in treating sepsis, and a new film, which aims to help clinicians spot and respond to warning signs of sepsis in children, has been launched by NHS Health Education England. The film, which features parents who lost their young daughter to undiagnosed sepsis, highlights the important signs clinicians should look for, and asks them to think 'could this be sepsis' when assessing children. It also highlights the wide range of learning resources available, including the new National Institute of Health and Care Excellence guidelines ( nice.org.uk/guidance/NG51 ). PMID:27581900

  15. Thin film photovoltaic device

    DOEpatents

    Catalano, A.W.; Bhushan, M.

    1982-08-03

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

  16. Current Film Periodicals in English. Revised Edition.

    ERIC Educational Resources Information Center

    Reilly, Adam, Comp.

    This bibliography of about 200 periodicals dealing with film covers several types of magazine: scholarly journals on film aesthetics, like "The Film Journal"; news notes for movie fans, like "Film Nut News"; magazines which cover films as well as the other arts, like "Cue" and "After Dark"; film education periodicals, like "Media and Methods";…

  17. Filming in decontamination by mopping

    SciTech Connect

    Rankin, W.N.; Toole, P.A.

    1993-09-28

    Technical assistance was provided High Level Waste Engineering in the investigation and prevention of filming during decontamination by mopping. After mopping operations in a Tank Farm application, a film of the cleaning agent sometimes remained on the surface being cleaned which interfered with monitoring to detect the presence of radioactive material. Scoping tests were conducted to investigate filming characteristics of two cleaning materials. In addition, rinsing test were conducted to demonstrate how filming can be prevented.

  18. Dual clearance squeeze film damper

    NASA Technical Reports Server (NTRS)

    Fleming, D. P. (Inventor)

    1985-01-01

    A dual clearance hydrodynamic liquid squeeze film damper for a gas turbine engine is described. Under normal operating conditions, the device functions as a conventional squeeze film damper, using only one of its oil films. When an unbalance reaches abusive levels, as may occur with a blade loss or foreign object damage, a second, larger clearance film becomes active, controlling vibration amplitudes in a near optimum manner until the engine can be safely shut down and repaired.

  19. NMR characterization of thin films

    DOEpatents

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  20. NMR characterization of thin films

    DOEpatents

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  1. Instructional Films: Asset or Liability?

    ERIC Educational Resources Information Center

    Braselman, Herbert P.

    1978-01-01

    The unique capabilities of film and research findings in educational psychology, learning psychology, and cost effectiveness indicate that film is an asset to the educational process. Sufficient resources and continued training should be provided to enable teachers to use the most effective film at the optimal time. (CMV)

  2. Film Images of the Negro.

    ERIC Educational Resources Information Center

    Manchel, Frank

    1967-01-01

    Educators can help students recognize the value of the motion picture as a social influence by exposing them to film stereotyping and the effect of this distortion on society. A historical study of the film image of the Negro will show him emerging from a humorous, fearful, "perverted" character in early films to "an unfortunate member of society"…

  3. Film Study in Higher Education.

    ERIC Educational Resources Information Center

    Stewart, David C., Ed.

    This resource book on the place of film study today is designed to assist in the planning of college courses in the history, criticism, and appreciation of motion pictures. Representative course descriptions and appraisals are given by (1) Jack C. Ellis, who describes a two-part course in film aesthetics and types of films, (2) Edward Fischer, who…

  4. Radical Pedagogy, Prison, and Film

    ERIC Educational Resources Information Center

    O'Neill, Dierdre

    2015-01-01

    This article explores the work of The Inside Film project. Inside Film works with a specific group of people (prisoners and ex-prisoners) in a particular set of circumstances (in prison or on parole) exploring how film making can be used within prison education or with people who have been to prison as a means of fostering a critical engagement…

  5. Nonfiction Film Theory and Criticism.

    ERIC Educational Resources Information Center

    Barsam, Richard Meran, Ed.

    This anthology offers significant writings on the subject of nonfiction film, with emphasis primarily on British and American films and film makers (although the work of Alberto Cavalcanti, Leni Riefenstahl, and Joris Ivens is also represented). The first section of the book offers essays that examine and define the essential nature and idea of…

  6. Archaeology on Film. Second Edition.

    ERIC Educational Resources Information Center

    Downs, Mary, Ed.; And Others

    This document provides a comprehensive guide to archaeological films and video tapes of archaeological interest. Individual films and film series are listed alphabetically by title. Each entry includes the following information: title, series, date, length, color/black & white, format, purchase and rental prices, distributor/rental source,…

  7. Longevity Of Dry Film Lubricants

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Stockwell, R. D.

    1993-01-01

    Report describes evaluation of dry film lubricants candidate for use in rotary joints of proposed Space Station. Study included experiments and theoretical analyses focused on longevity of sputtered molybdenum disulfide films and ion-plated lead films under conditions partially simulating rolling contact.

  8. Teaching Argumentative Writing through Film.

    ERIC Educational Resources Information Center

    Fluitt-Dupuy, Jan

    2001-01-01

    Discusses how watching and discussing feature films and writing reviews of these films in the English-as-a-Second/Foreign-Language classroom can be instrumental in teaching the principles of good argumentative writing within the confines of the simple movie review. Six steps for teaching a film review unit are provided. (Author/VWL)

  9. Methods for producing complex films, and films produced thereby

    DOEpatents

    Duty, Chad E.; Bennett, Charlee J. C.; Moon, Ji -Won; Phelps, Tommy J.; Blue, Craig A.; Dai, Quanqin; Hu, Michael Z.; Ivanov, Ilia N.; Jellison, Jr., Gerald E.; Love, Lonnie J.; Ott, Ronald D.; Parish, Chad M.; Walker, Steven

    2015-11-24

    A method for producing a film, the method comprising melting a layer of precursor particles on a substrate until at least a portion of the melted particles are planarized and merged to produce the film. The invention is also directed to a method for producing a photovoltaic film, the method comprising depositing particles having a photovoltaic or other property onto a substrate, and affixing the particles to the substrate, wherein the particles may or may not be subsequently melted. Also described herein are films produced by these methods, methods for producing a patterned film on a substrate, and methods for producing a multilayer structure.

  10. Growth and surface characterization of tin-doped indium oxide thin films

    NASA Astrophysics Data System (ADS)

    Morales, Erie

    The geometrical and electronic surface properties of In2O 3 and Sn-doped In2O3 (ITO) have been investigated. Sn-doped In2O3 is widely used as a transparent conducting oxide in flat panel displays, organic-light-emitting-diodes, solar cells, and electrochromic windows. Despite the fact that surface and interfaces are important in all these applications, a fundamental understanding of the surface properties of this material is lacking. Meaningful surface investigations are best conducted on single-crystalline samples, thus epitaxial thin films of In2O3 and ITO were grown and used as samples for the surface investigations. This work focuses on two low-index surfaces of ITO, the non-polar (111) orientation and the (100) orientation, which, in its bulk-terminated form, is polar. The epitaxial films were grown with oxygen-plasma assisted molecular beam epitaxy (MBE) on yttria-stabilized zirconia, which exhibits a cube-on-cube epitaxy as well as a small lattice mismatch with respect to In2O 3. The YSZ(111) substrate was characterized with Re ection-high-electron-energy-diffraction (RHEED) and Low-energy-electron-diffraction (LEED) and its surface was found to be (1x1) terminated. RHEED and LEED measurements on the substrate were possible if the substrate was kept at 300°C in order to avoid charging effects of this insulating material. RHEED exhibited 2-dimensional growth mode for the Sn-doped In2O3 thin films. Using LEED it was found that the surface of In2O3 and Sn-doped In 2O3 poses a (1x1) terminated surface. A de-convolution of X-ray core level photoemission (XPS) of In 3d peaks; into one component that is due to regular photoemission and one that is due to interaction of core holes with electronic plasmons, provided the plasmon energy, E p; From Ep the electron density n of the doped films was obtained. For an ITO film with 6.2 at% of Sn, it was found that 1/3 of the Sn atoms contribute one electron to the conduction band. Scanning-tunneling-microscopy (STM) was

  11. Museums With Film Programs.

    ERIC Educational Resources Information Center

    Melton, Hollis, Comp.

    Selectively listed by state are the names and addresses of museums in the U.S., Canada, and Puerto Rico which feature film programs as part of their regular activities. The list, acknowledged to be less than complete, includes some natural history and science museums, some anthropology museums, and state and county historical societies. The…

  12. Mobile Library Filming Device.

    ERIC Educational Resources Information Center

    Martin, Claud E.

    This report contains details of the study and performance test of the Mobile Filming Library Device which consists of a camera and self contained power source. Because of the cost savings and service improvement characteristics, this technique involving the use of a microfilm intermediate in the preparation of copies of material filed in full size…

  13. Film, Radio, and Television.

    ERIC Educational Resources Information Center

    Hardesty, Carolyn, Ed.

    1990-01-01

    This journal issue covers the history of film, radio, and television in Iowa. The first article, "When Pictures and Sound Came to Iowa," summarizes the origin of movies and radio and their early beginnings in Iowa. Using old photographs and measurement charts, the viewing, reading, and listening habits of young people in 1950 and 1958 are…

  14. Intercultural Training with Films

    ERIC Educational Resources Information Center

    Roell, Christine

    2010-01-01

    Films are a great medium to use not only to practice English, but also to facilitate intercultural learning. Today English is a global language spoken by people from many countries and cultural backgrounds. Since culture greatly impacts communication, it is helpful for teachers to introduce lessons and activities that reveal how different…

  15. Film: The Creative Eye.

    ERIC Educational Resources Information Center

    Sohn, David A.

    Short films are often experimental in nature. They can place aspects of the environment which are usually unnoticed in such a way as to sharpen our observations of the world, and "create a new awareness, a fuller sense of life and being." Based on the premise that visual literacy is becoming increasingly important, this book describes several…

  16. Paradoxes in Film Ratings

    ERIC Educational Resources Information Center

    Moore, Thomas L.

    2006-01-01

    The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

  17. Introduction to Film.

    ERIC Educational Resources Information Center

    Burns, Gary

    There are numerous ways to structure the introduction to film course so as to meet the needs of the different types of students who typically enroll. Assuming there is no production component in the course, the teacher is left with two major approaches to choose from--historical and aesthetic. The units in the course will typically be built around…

  18. Thin film photovoltaic cell

    DOEpatents

    Meakin, John D.; Bragagnolo, Julio

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  19. Diamond films: Historical perspective

    SciTech Connect

    Messier, R.

    1993-01-01

    This section is a compilation of notes and published international articles about the development of methods of depositing diamond films. Vapor deposition articles are included from American, Russian, and Japanese publications. The international competition to develop new deposition methodologies is stressed. The current status of chemical vapor deposition of diamond is assessed.

  20. Films on Deafness.

    ERIC Educational Resources Information Center

    Parlato, Salvatore J., Jr., Comp.

    This filmography on deafness, which contains summaries of 192 16mm films arranged in alphabetical order by title, covers a wide variety of topics as evidenced by the categorical title index: communication, the nature of deafness, detection and measurement of deafness, education and training, multi-handicaps, and noise pollution. Running time, date…

  1. Films in Depth.

    ERIC Educational Resources Information Center

    Schrievogel, Paul A.; Prete, Anthony T.

    Bound in a slipcover rather than in signatures, this "book" is made up of thirteen separately bound booklets. The first booklet is an introduction to the use of film in the classroom both in teaching the filmic art and in increasing the visual literacy of students on the high school and early college levels. The twelve other booklets each treat a…

  2. A Film Canister Colorimeter.

    ERIC Educational Resources Information Center

    Gordon, James; James, Alan; Harman, Stephanie; Weiss, Kristen

    2002-01-01

    A low-cost, low-tech colorimeter was constructed from a film canister. The student-constructed colorimeter was used to show the Beer-Lambert relationship between absorbance and concentration and to calculate the value of the molar absorptivity for permanganate at the wavelength emission maximum for an LED. Makes comparisons between this instrument…

  3. Rating Films on TV.

    ERIC Educational Resources Information Center

    Herman, Ginette; Leyens, Jacques-Philippe

    1977-01-01

    An analysis of the film viewing habits of Belgian television viewers reveals that movies with advisories regarding sex and violence are watched more than the movies without them. However, movies with qualifications tend to be judged less interesting than movies without qualifications. (JMF)

  4. Films: 1971/72 Catalog of Films, Film Loops and Filmstrips for Schools, Colleges and Libraries.

    ERIC Educational Resources Information Center

    Learning Corp. of America, New York, NY.

    The films in this catalog are available for sale or rent from Learning Corporation of America. For elementary grades, films are available for use in the language arts and social studies classes. For junior and senior high, college, and adult courses, films are listed for instruction in art, music, and dance; environmental studies; United States…

  5. Orientation filtering for crystalline films

    DOEpatents

    Smith, H.I.; Atwater, H.A.; Thompson, C.V.; Geis, M.W.

    1986-12-30

    A substrate is coated with a film to be recrystallized. A pattern of crystallization barriers is created in the film, for example, by etching voids in the film. An encapsulation layer is generally applied to protect the film, fill the voids and otherwise enhance a recrystallization process. Recrystallization is carried out such that certain orientations pass preferentially through the barrier, generally as a result of growth-velocity anisotropy. The result is a film of a specific predetermined crystallographic orientation, a range of orientations or a set of discrete orientations. 7 figs.

  6. Orientation filtering for crystalline films

    DOEpatents

    Smith, Henry I.; Atwater, Harry A.; Thompson, Carl V.; Geis, Michael W.

    1986-12-30

    A substrate is coated with a film to be recrystallized. A pattern of crystallization barriers is created in the film, for example, by etching voids in the film. An encapsulation layer is generally applied to protect the film, fill the voids and otherwise enhance a recrystallization process. Recrystallization is carried out such that certain orientations pass preferentially through the barrier, generally as a result of growth-velocity anisotropy. The result is a film of a specific predetermined crystallographic orientation, a range of orientations or a set of discrete orientations.

  7. Process to form mesostructured films

    DOEpatents

    Brinker, C. Jeffrey; Anderson, Mark T.; Ganguli, Rahul; Lu, Yunfeng

    1999-01-01

    This invention comprises a method to form a family of supported films film with pore size in the approximate range 0.8-20 nm exhibiting highly ordered microstructures and porosity derived from an ordered micellar or liquid-crystalline organic-inorganic precursor structure that forms during film deposition. Optically transparent, 100-500-nm thick films exhibiting a unique range of microstructures and uni-modal pore sizes are formed in seconds in a continuous coating operation. Applications of these films include sensors, membranes, low dielectric constant interlayers, anti-reflective coatings, and optical hosts.

  8. Why do drying films crack?

    PubMed

    Lee, Wai Peng; Routh, Alexander F

    2004-11-01

    Understanding the mechanism by which films fail during drying is the first step in controlling this natural process. Previous studies have examined the spacing between cracks with predictions made by assuming a balance between elastic energy released with a surface energy consumed. We introduce a new scaling for the spacing between cracks in drying dispersions. The scaling relates to the distance that solvent can flow, to relieve capillary stresses, as a film fails. The scaling collapses data for a range of evaporation rates, film thicknesses, particle sizes, and materials. This work identifies capillary pressures, induced by packed particle fronts travelling horizontally across films, as responsible for the failure in dried films. PMID:15518466

  9. Thin-film optical initiator

    DOEpatents

    Erickson, Kenneth L.

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  10. Combustion effects on film cooling

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Ewen, R. L.

    1977-01-01

    The effects of: (1) a reactive environment on film cooling effectiveness, and (2) film cooling on rocket engine performance were determined experimentally in a rocket thrust chamber assembly operating with hydrogen and oxygen propellants at 300 psi chamber pressure. Tests were conducted using hydrogen, helium, and nitrogen film coolants in an instrumented, thin walled, steel thrust chamber. The film cooling, performance loss, and heat transfer coefficient data were correlated with the ALRC entrainment film cooling model which relates film coolant effectiveness and mixture ratio at the wall to the amount of mainstream gases entrained with the film coolant in a mixing layer. In addition, a comprehensive thermal analysis computer program, HOCOOL, was prepared from previously existing ALRC computer programs and analytical techniques.

  11. Professor Camillo Negro's Neuropathological Films.

    PubMed

    Chiò, Adriano; Gianetto, Claudia; Dagna, Stella

    2016-01-01

    Camillo Negro, Professor in Neurology at the University of Torino, was a pioneer of scientific film. From 1906 to 1908, with the help of his assistant Giuseppe Roasenda and in collaboration with Roberto Omegna, one of the most experienced cinematographers in Italy, he filmed some of his patients for scientific and educational purposes. During the war years, he continued his scientific film project at the Military Hospital in Torino, filming shell-shocked soldiers. In autumn 2011, the Museo Nazionale del Cinema, in partnership with the Faculty of Neurosciences of the University of Torino, presented a new critical edition of the neuropathological films directed by Negro. The Museum's collection also includes 16 mm footage probably filmed in 1930 by Doctor Fedele Negro, Camillo's son. One of these films is devoted to celebrating the effects of the so-called "Bulgarian cure" on Parkinson's disease. PMID:26684422

  12. Thin film superconductor magnetic bearings

    DOEpatents

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  13. Method for making carbon films

    DOEpatents

    Tan, M.X.

    1999-07-29

    A method for treating an organic polymer material, preferably a vinylidene chloride/vinyl chloride copolymer (Saran) to produce a flat sheet of carbon film material having a high surface area ([approx equal]1000 m[sup 2] /g) suitable as an electrode material for super capacitor applications. The method comprises heating a vinylidene chloride/vinyl chloride copolymer film disposed between two spaced apart graphite or ceramic plates to a first temperature of about 160 C for about 14 hours to form a stabilized vinylidene chloride/vinyl chloride polymer film, thereafter heating the stabilized film to a second temperature of about 750 C in an inert atmosphere for about one hour to form a carbon film; and finally activating the carbon film to increase the surface area by heating the carbon film in an oxidizing atmosphere to a temperature of at least 750--850 C for between 1--6 hours. 2 figs.

  14. Method for making carbon films

    DOEpatents

    Tan, Ming X.

    1999-01-01

    A method for treating an organic polymer material, preferably a vinylidene chloride/vinyl chloride copolymer (Saran) to produce a flat sheet of carbon film material having a high surface area (.apprxeq.1000 m.sup.2 /g) suitable as an electrode material for super capacitor applications. The method comprises heating a vinylidene chloride/vinyl chloride copolymer film disposed between two spaced apart graphite or ceramic plates to a first temperature of about 160.degree. C. for about 14 hours to form a stabilized vinylidene chloride/vinyl chloride polymer film, thereafter heating the stabilized film to a second temperature of about 750.degree. C. in an inert atmosphere for about one hour to form a carbon film; and finally activating the carbon film to increase the surface area by heating the carbon film in an oxidizing atmosphere to a temperature of at least 750-850.degree. C. for between 1-6 hours.

  15. Thin film superconductor magnetic bearings

    SciTech Connect

    Weinberger, B.R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft that is subject to a load (L) and rotatable around an axis of rotation, a magnet mounted to the shaft, and a stator in proximity to the shaft. The stator has a superconductor thin film assembly positioned to interact with the magnet to produce a levitation force on the shaft that supports the load (L). The thin film assembly includes at least two superconductor thin films and at least one substrate. Each thin film is positioned on a substrate and all the thin films are positioned such that an applied magnetic field from the magnet passes through all the thin films. A similar bearing in which the thin film assembly is mounted on the shaft and the magnet is part of the stator also can be constructed. 8 figs.

  16. Host thin films incorporating nanoparticles

    NASA Astrophysics Data System (ADS)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  17. Thin film mechanics

    NASA Astrophysics Data System (ADS)

    Cooper, Ryan C.

    This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate

  18. thin films as absorber

    NASA Astrophysics Data System (ADS)

    González, J. O.; Shaji, S.; Avellaneda, D.; Castillo, G. A.; Das Roy, T. K.; Krishnan, B.

    2014-09-01

    Photovoltaic structures were prepared using AgSb(S x Se1- x )2 as absorber and CdS as window layer at various conditions via a hybrid technique of chemical bath deposition and thermal evaporation followed by heat treatments. Silver antimony sulfo selenide thin films [AgSb(S x Se1- x )2] were prepared by heating multilayers of sequentially deposited Sb2S3/Ag dipped in Na2SeSO3 solution, glass/Sb2S3/Ag/Se. For this, Sb2S3 thin films were deposited from a chemical bath containing SbCl3 and Na2S2O3. Then, Ag thin films were thermally evaporated on glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of dipping was varied as 3, 4 and 5 h. Two different heat treatments, one at 350 °C for 20 min in vacuum followed by a post-heat treatment at 325 °C for 2 h in Ar, and the other at 350 °C for 1 h in Ar, were applied to the multilayers of different configurations. X-ray diffraction results showed the formation of AgSb(S x Se1- x )2 thin films as the primary phase and AgSb(S,Se)2 and Sb2S3 as secondary phases. Morphology and elemental detection were done by scanning electron microscopy and energy dispersive X-ray analysis. X-ray photoelectron spectroscopic studies showed the depthwise composition of the films. Optical properties were determined by UV-vis-IR transmittance and reflection spectral analysis. AgSb(S x Se1- x )2 formed at different conditions was incorporated in PV structures glass/FTO/CdS/AgSb(S x Se1- x )2/C/Ag. Chemically deposited post-annealed CdS thin films of various thicknesses were used as window layer. J- V characteristics of the cells were measured under dark and AM1.5 illumination. Analysis of the J- V characteristics resulted in the best solar cell parameters of V oc = 520 mV, J sc = 9.70 mA cm-2, FF = 0.50 and η = 2.7 %.

  19. Rupture of vertical soap films

    NASA Astrophysics Data System (ADS)

    Rio, Emmanuelle

    2014-11-01

    Soap films are ephemeral and fragile objects. They tend to thin under gravity, which gives rise to the fascinating variations of colors at their interfaces but leads systematically to rupture. Even a child can create, manipulate and admire soap films and bubbles. Nevertheless, the reason why it suddenly bursts remains a mystery although the soap chosen to stabilize the film as well as the humidity of the air seem very important. One difficulty to study the rupture of vertical soap films is to control the initial solution. To avoid this problem we choose to study the rupture during the generation of the film at a controlled velocity. We have built an experiment, in which we measure the maximum length of the film together with its lifetime. The generation of the film is due to the presence of a gradient of surface concentration of surfactants at the liquid/air interface. This leads to a Marangoni force directed toward the top of the film. The film is expected to burst only when its weight is not balanced anymore by this force. We will show that this leads to the surprising result that the thicker films have shorter lifetimes than the thinner ones. It is thus the ability of the interface to sustain a surface concentration gradient of surfactants which controls its stability.

  20. Advanced thin film thermocouples

    NASA Astrophysics Data System (ADS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-10-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  1. Freely floating smectic films.

    PubMed

    May, Kathrin; Harth, Kirsten; Trittel, Torsten; Stannarius, Ralf

    2014-05-19

    We have investigated the dynamics of freely floating smectic bubbles using high-speed optical imaging. Bubbles in the size range from a few hundred micrometers to several centimeters were prepared from collapsing catenoids. They represent ideal model systems for the study of thin-film fluid dynamics under well-controlled conditions. Owing to the internal smectic layer structure, the bubbles combine features of both soap films and vesicles in their unique shape dynamics. From a strongly elongated initial shape after pinch-off, they relax towards the spherical equilibrium, first by a slow redistribution of the smectic layers, and finally by weak, damped shape oscillations. In addition, we describe the rupture of freely floating smectic bubbles, and the formation and stability of smectic filaments. PMID:24692347

  2. Biomimetic thin film deposition

    SciTech Connect

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  3. Advanced thin film thermocouples

    NASA Technical Reports Server (NTRS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-01-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  4. Molecular films associated with LDEF

    NASA Technical Reports Server (NTRS)

    Crutcher, E. R.; Warner, K. J.

    1992-01-01

    The molecular films deposited on the surface of the Long Duration Exposure Facility (LDEF) originated from the paints and room-temperature-vulcanized (RTV) silicone materials intentionally used on the satellite and not from residual contaminants. The high silicone content of most of the films and the uniformity of the films indicates a homogenization process in the molecular deposition and suggests a chemically most favored composition for the final film. The deposition on interior surfaces and vents indicated multiple bounce trajectories or repeated deposition-reemission cycles. Exterior surface deposits indicated a significant return flux. Ultraviolet light exposure was required to fix the deposited film as is indicated by the distribution of the films on interior surfaces and the thickness of films at the vent locations. Thermal conditions at the time of exposure to ultraviolet light seems to be an important factor in the thickness of the deposit. Sunrise facing (ram direction) surfaces always had the thicker film. These were the coldest surfaces at the time of their exposure to ultraviolet light. The films have a layered structure suggesting cyclic deposition. As many as 34 distinct layers were seen in the films. The cyclic nature of the deposition and the chemical uniformity of the film one layer to the next suggest an early deposition of the films though there is evidence for the deposition of molecular films throughout the nearly six year exposure of the satellite. A final 'spray' of an organic material associated with water soluble salts occurred very late in the mission. This may have been the result of one of the shuttle dump activities.

  5. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  6. Falling film evaporator

    DOEpatents

    Bruns, Lester E.

    1976-01-01

    A falling film evaporator including a vertically oriented pipe heated exteriorly by a steam jacket and interiorly by a finned steam tube, all heating surfaces of the pipe and steam tube being formed of a material wet by water such as stainless steel, and packing within the pipe consisting of Raschig rings formed of a material that is not wet by water such as polyvinylidene fluoride.

  7. Thick film ink chemistry

    NASA Astrophysics Data System (ADS)

    Gehman, R. W.

    1982-03-01

    Twenty-six thick film inks from two vendors were proved for hybrid microcircuit production use. A data base of chemical information was established for all the inks to aid in future diagnostic and failure analysis activities. Efforts included both organic chemical analysis of printing vehicles and binders and inorganic chemical analysis of glass frits and electrically active phases. Analytical methods included infrared spectroscopy, mass spectroscopy, gas chromatography, X-ray fluorescence, emission spectroscopy, atomic absorption spectroscopy, and wet chemical techniques.

  8. Polycrystalline thin film photovoltaics

    NASA Astrophysics Data System (ADS)

    Zweibel, K.; Ullal, H. S.; Mitchell, R. L.

    Significant progress has recently been made towards improving the efficiencies of polycrystalline thin-film solar cells and modules using CuInSe2 and CdTe. The history of using CuInSe2 and CdTe for solar cells is reviewed. Initial outdoor stability tests of modules are encouraging. Progress in semiconductor deposition techniques has also been substantial. Both CuInSe2 and CdTe are positioned for commercialization during the 1990s. The major participants in developing these materials are described. The US DOE/SERI (Solar Energy Research Institute) program recognizes the rapid progress and important potential of polycrystalline thin films to meet ambitious cost and performance goals. US DOE/SERI is in the process of funding an initiative in this area with the goal of ensuring US leadership in the development of these technologies. The polycrystalline thin-film module development initiative, the modeling and stability of the devices, and health and safety issues are discussed.

  9. Spring magnet films.

    SciTech Connect

    Bader, S. D.; Fullerton, E. E.; Gornakov, V. S.; Inomata, A.; Jiang, J. S.; Nikitenko, V. I.; Shapiro, A. J.; Shull, R. D.; Sowers, C. H.

    1999-03-29

    The properties of exchange-spring-coupled bilayer and superlattice films are highlighted for Sm-Co hard magnet and Fe or Co soft magnet layers. The hexagonal Sm-Co is grown via magnetron sputtering in a- and b-axis epitaxial orientations. In both cases the c-axis, in the film plane, is the easy axis of magnetization. Trends in coercivity with film thickness are established and related to the respective microstructure of the two orientations. The magnetization reversal process for the bilayers is examined by magnetometry and magneto-optical imaging, as well as by simulations that utilize a one-dimensional model to provide the spin configuration for each atomic layer. The Fe magnetization is pinned to that of the Sm-Co at the interface, and reversal proceeds via a progressive twisting of the Fe magnetization. The Fe demagnetization curves are reversible as expected for a spring magnet. Comparison of experiment and simulations indicates that the spring magnet behavior can be understood from the intrinsic properties of the hard and soft layers. Estimated are made of the ultimate gain in performance that can potentially be realized in this system.

  10. Short Films for Physics Teaching, A Catalog.

    ERIC Educational Resources Information Center

    Bluestone, Barbara Z.; Roth, Richard F.

    This annotated film catalog is a product of the Conference on Single Concept Films in College Physics Teaching sponsored by the Commission on College Physics. Both 8mm and 16mm single concept films are listed for physics and related disciplines. The catalog includes commercial, noncommercial, and foreign films. However, the film coverage was…

  11. Cathodoluminescence and depth profiling studies of unintentionally doped GaN films grown by MOVPE

    NASA Astrophysics Data System (ADS)

    Tounsi, Nabil; Guermazi, Hajer; Guermazi, Samir; El Jani, Belgacem

    2015-10-01

    GaN layers are grown by metalorganic vapor phase epitaxy at 1050 °C on porous silicon and (111) oriented silicon substrates. AlN buffer layers of about 100 nm thickness were previously deposited on Si substrates. The effect of substrates on optical properties is revealed by Cathodoluminescence measurements (CL), recorded at room temperature and liquid nitrogen temperature. Various excitonic transitions are depicted. Spectral features associated with F°X energy around 3.4 eV and bound excitons (D°X and A°X in the range 3.29-3.35 eV) related to wurtzite GaN excitons are observed. Yellow band is located around 2.15 eV. CL depth profiling is also investigated at various e-beam energies (3-25 keV). The low-energy electron beam irradiation reveals an inhomogeneous distribution of point defects in depth, and high non-radiative recombination beyond a threshold energy. Good agreement between our experimental data and literature is obtained. Moreover, CL investigations prove that growth of GaN on (111) oriented Si substrate improve the crystalline quality of the layer.

  12. Films on the arms race

    SciTech Connect

    Dowling, J.

    1983-01-01

    Films convey the historical perspectives, the biographical stories, the insights of the participants, and the horror of nuclear war - far better than can any physicist. While films are not very efficient for covering details, derivation, or numbers, they can not be beaten in showing what really happens in a nuclear explosion, in getting across general concepts, in illustrating the parameters of a problem, and the problem itself. Most importantly, films and TV can reach the people who must be informed about these issues if we are to resolve the problems. The author points out how films can contribute to an understanding of the issues of the arms race and nuclear war, with references to specific films. An annotated bibliography of 37 films is then presented.

  13. Fracture characteristics of balloon films

    NASA Technical Reports Server (NTRS)

    Portanova, Marc A.

    1989-01-01

    An attempt was made to determine the failure modes of high altitude scientific balloons through an investigation of the fracture characteristics of the thin polyethylene films. Two films were the subject of the evaluation, Winzen Int.'s Stratafilm SF-85 and Raven Industries' Astro-E. Research began with an investigation of the film's cold brittleness point and it's effect on the ultimate strength and elasticity of the polyethylene film. A series of preliminary investigations were conducted to develop an understanding of the material characteristics. The primary focus of this investigation was on the notch sensitivity of the films. Simple stress strain tests were also conducted to enable analysis employing fracture toughness parameters. Studies were conducted on both film types at 23 C (room temperature), -60 C, -90 C, and -120 C.

  14. How to Read a Film: The Art, Technology, Language, History and Theory of Film and Media.

    ERIC Educational Resources Information Center

    Monaco, James

    This book discusses film as a narrative technique directly comparable to expression in prose narrative, in painting, and in music; it presents an overview of film as technology, the language of film and television, the history of film in America, Europe, and Asia, and the growth of film criticism. Chapters include "Film As an Art,""Technology:…

  15. Frequency mixer having ferromagnetic film

    DOEpatents

    Khitun, Alexander; Roshchin, Igor V.; Galatsis, Kosmas; Bao, Mingqiang; Wang, Kang L.

    2016-03-29

    A frequency conversion device, which may include a radiofrequency (RF) mixer device, includes a substrate and a ferromagnetic film disposed over a surface of the substrate. An insulator is disposed over the ferromagnetic film and at least one microstrip antenna is disposed over the insulator. The ferromagnetic film provides a non-linear response to the frequency conversion device. The frequency conversion device may be used for signal mixing and amplification. The frequency conversion device may also be used in data encryption applications.

  16. Diamond films for laser hardening

    NASA Technical Reports Server (NTRS)

    Albin, S.; Watkins, L.; Ravi, K.; Yokota, S.

    1989-01-01

    Laser-damage experiments were performed on free-standing polycrystalline diamond films prepared by plasma-enhanced CVD. The high laser-induced stress resistance found for this material makes it useful for thin-film coatings for laser optics. Results for diamond-coated silicon substrates demonstrate the enhanced damage threshold imparted by diamond thin-film coatings to materials susceptible to laser damage.

  17. Polycrystalline thin film photovoltaic technology

    SciTech Connect

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L.; Noufi, R.

    1991-03-01

    Low-cost, high-efficiency thin-film modules are an exciting photovoltaic technology option for generating cost-effective electricity in 1995 and beyond. In this paper we review the significant technical progress made in the following thin films: copper indium diselenide, cadmium telluride, and polycrystalline thin silicon films. Also, the recent US DOE/SERI initiative to commercialize these emerging technologies is discussed. 6 refs., 9 figs.

  18. Chitosan composite films. Biomedical applications.

    PubMed

    Cárdenas, Galo; Anaya, Paola; von Plessing, Carlos; Rojas, Carlos; Sepúlveda, Jackeline

    2008-06-01

    Chitosan acetate films have been prepared using chitosans from shrimps (Pleuroncodes monodon) of low and high molecular weight (LMv = 68,000 g/mol and HMv = 232,000 g/mol) and deacetylation degree of 80 and 100%, respectively. The chitosan films were obtained by addition of several additives to acetic acid chitosan solutions, such as: glycerol, oleic acid and linoleic acid in different proportions. The pH of the solutions before casting ranged from 5.0 to 6.0. The composite film thickness are reported. The films have been analyzed by FTIR showing characteristic bands corresponding to the additives. The scanning electron microscopy (SEM) studies reveals the different morphology of the composite films. The films exhibit different physical properties depending upon the additives and/or mixture of them. The addition of glycerol to composite improves the elasticity of the films. The swelling in glucose and saline solutions for several films was evaluated, being higher in the glucose solution. The bactericide test against Staphylococcus aureus, Pseudomona aeruginosa and Acinetobacter baumanii in plates with either blood and or agar tripticase showed that the molecular weight influences on the bactericidal properties of the chitosan composite films and over its effect against gram positive and gram negative bacteria. Medical applications of the composite films were done in patients with burns, ulcers and injuries, the films containing glycerol showed good adhesion in comparison with those without it. The composite films tested were mainly three (1) chitosan acetate with glycerol, (2) chitosan acetate with oleic acid and (3) chitosan acetate with glycerol and oleic acid. Excellent results in the skin recovery were obtained after 7-10 days. Since the chitosan is biodegradable by the body enzymes it does not need to be removed and increases the gradual grows of the damage tissues. PMID:18165888

  19. Communicating Science: Lessons from Film.

    PubMed

    Berlin, Heather A

    2016-04-01

    Films engage us visually, aurally, viscerally, and emotionally. Incorporating science themes into films has the potential to open up new audiences to scientific ideas, pique their interests, and inspire them to engage in a broader discussion of the science itself. Here, I discuss several narrative techniques and strategies employed in film to effectively engage the audience around science themes, which may be useful tools for scientists looking to become better communicators. PMID:26988314

  20. Center for thin film studies

    NASA Astrophysics Data System (ADS)

    Shannon, Robert P.; Gibson, Ursula J.

    1987-11-01

    This report covers the first year of operation of the URI Thin Film Center (TFC), and describes a diverse array of studies on thin-film materials, substrates, and their processing and analysis. Individual efforts are highlighted in sections on nucleation studies, ion-assisted deposition, Rutherford backscattering spectrometry, Brillouin scattering, a continuum theory of the evolution of structure in thin films, a study of polishing parameters relevant to the preparation of substrates, and the setup of a characterization facility for the Center.

  1. Process to form mesostructured films

    DOEpatents

    Brinker, C.J.; Anderson, M.T.; Ganguli, R.; Lu, Y.F.

    1999-01-12

    This invention comprises a method to form a family of supported films with pore size in the approximate range 0.8-20 nm exhibiting highly ordered microstructures and porosity derived from an ordered micellar or liquid-crystalline organic-inorganic precursor structure that forms during film deposition. Optically transparent, 100-500-nm thick films exhibiting a unique range of microstructures and uni-modal pore sizes are formed in seconds in a continuous coating operation. Applications of these films include sensors, membranes, low dielectric constant interlayers, anti-reflective coatings, and optical hosts. 12 figs.

  2. Ratings for emotion film clips.

    PubMed

    Gabert-Quillen, Crystal A; Bartolini, Ellen E; Abravanel, Benjamin T; Sanislow, Charles A

    2015-09-01

    Film clips are widely utilized to elicit emotion in a variety of research studies. Normative ratings for scenes selected for these purposes support the idea that selected clips correspond to the intended target emotion, but studies reporting normative ratings are limited. Using an ethnically diverse sample of college undergraduates, selected clips were rated for intensity, discreteness, valence, and arousal. Variables hypothesized to affect the perception of stimuli (i.e., gender, race-ethnicity, and familiarity) were also examined. Our analyses generally indicated that males reacted strongly to positively valenced film clips, whereas females reacted more strongly to negatively valenced film clips. Caucasian participants tended to react more strongly to the film clips, and we found some variation by race-ethnicity across target emotions. Finally, familiarity with the films tended to produce higher ratings for positively valenced film clips, and lower ratings for negatively valenced film clips. These findings provide normative ratings for a useful set of film clips for the study of emotion, and they underscore factors to be considered in research that utilizes scenes from film for emotion elicitation. PMID:24984981

  3. Thin film of biocompatible polysaccharides

    NASA Astrophysics Data System (ADS)

    Richert, Ludovic; Lavalle, Philippe; Schaaf, Pierre; Voegel, Jean-Claude; Picart, Catherine

    2003-03-01

    The layer-by-layer deposition method proposed by Decher et al. (1991) is a very simple and versatile method used to build thin films. These films are of interest for bioengineering because of their unique properties and of the possible insertion of bioactive molecules. We present here the peculiar properties of a new kind of film formed with natural biopolymers, namely hyaluronan (HA)and chitosan (CHI). The films may be used as biomimetic substrates to control bacterial and cell adhesion. These polysaccharides are of particular interest because they are biodegradable, non toxic, and can be found in various tissues. Hyaluronan is also a natural ligand for a numerous type of cells through the CD44 receptor. Chitosan has already largely been used for its biological and anti-microbial properties. (CHI/HA) films were built in acidic pH at different ionic strength. The buildup was followed in situ by optical waveguide lightmode spectroscopy (OWLS), quartz crystal microbalance, streaming potential measurements and atomic force microscopy. The kinetics of adsorption and desorption of the polyelectrolytes depended on the ionic strength. Small islands were initially present on the surface which grew by mutual coalescence until becoming a flat film. The films were around 200 nm in thickness. These results suggest that different types of thin films constituted of polysaccharides can be built on any type of surface. These films are currently investigated toward their cell adhesion and bacterial adhesion properties.

  4. Optical limiting by chemically enhanced bacteriorhodopsin films

    NASA Astrophysics Data System (ADS)

    Song, Q. Wang; Zhang, Chungping; Gross, Richard; Birge, Robert

    1993-05-01

    Measurements of effective nonlinearity of a chemically enhanced bacteriorhodopsin film are presented, using 2-scan method. Optical limiting properties and the film's nonlinear transmission properties of the film are also studied.

  5. Film Review. Films for Use in Professional Courses.

    ERIC Educational Resources Information Center

    Graham, Mike, Ed.

    This book contains a detailed review of over ninety films in the professional preparation of teachers. It is one of eight publications which have been produced by the Science Teacher Education Project. Some of the films have become integral parts of the learning experiences which college and university people have prepared and others are…

  6. The Environment Film Review. A Critical Guide to Ecology Films.

    ERIC Educational Resources Information Center

    Environment Information Center, New York, NY.

    Critical reviews of more than 600 environmental films selected from a field of several thousand are contained in this reference guide. Designed to provide a comprehensive selection of films covering all aspects of environmental affairs, from air pollution to wildlife, the guide is primarily user-oriented. It consists of two parts: a Review…

  7. "Kuleshov on Film": A Spectator-Centered Film Theory.

    ERIC Educational Resources Information Center

    Curran, Trisha

    This paper describes some of the theories of cinematography of Soviet film theorist and filmmaker Lev Kuleshov. It points out that for him, film was communication portraying people's activities emanating from the environment. It explains that he was especially interested in audience response, particularly that of the proletariat, and that he felt…

  8. Study of transparent conductive oxides and back reflectors for amorphous and nano-crystalline silicon based thin film solar cells

    NASA Astrophysics Data System (ADS)

    Yang, Xiesen

    2007-12-01

    In this dissertation, back reflectors (BR) for hydrogenated amorphous silicon (a-Si:H) and hydrogenated nanocrystalline silicon (nc-Si:H) based solar cells have been systematically studied. The main results achieved in the dissertation are as follows: (1) By using the optical scattering theory and PVOPTICS simulation program, it is found that to characterize the texture of the BR, not only the texture height, but also the texture angle (which is usually not mentioned in the literature) is needed. Moreover, the optical scattering of a rough surface is mainly determined by the texture angle. Experimentally the texture angle has been calculated from the raw AFM data for our BR samples using a FORTRAN program. (2) It has been deduced in this dissertation that the light trapping scheme with ideal rough BR should have an effective light path enhancement factor of n(n+1)2 in the absorption media (with refractive index n), rather than 4n2, the generally quoted value in references. In the case of Si as the absorption media this factor could be 25% larger than 4n2. (3) The optical and textural properties of Al and Ag have been studied. The results obtained show that Ag film has an improved reflectance in the long wavelength range and 5 times higher deposition rate than Al films deposited at the same conditions. It is found that Ag films have random orientation and are difficult to get a large texture angle and height profile; so in order to get enough texture for application in solar cells Ag needs a high deposition temperature (Ts) of 300 ˜ 400°C. In contrast, Al films have preferred (111) orientation and are easy to get large texture angle and height profiles. The impacts of deposition rate on the morphology of Ag and Al films have also been compared. (4) On the basis of understanding of the optical and textural properties of Al and Ag, a stacked configuration of ZnO/Ag/Al BR has been studied. It shows a high total reflectance comparable to ZnO/Ag structure and a high

  9. Protective Film Moves Aside

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Relatively warmer daytime temperatures on Mars have allowed the biobarrier -- a shiny, protective film -- to peel away a little more from the robotic arm of NASA's Phoenix Mars Lander.

    This image shows the spacecraft's robotic arm in its stowed configuration, with the biobarrier unpeeled on landing day, or Sol (Martian day) 0, and the lander's first full day on Mars, Sol 1.

    The 'elbow' of the arm can be seen at the top center of the picture, and the biobarrier is the shiny film seen to the left of the arm.

    The biobarrier is an extra precaution to protect Mars from contamination with any bacteria from Earth. While the whole spacecraft was decontaminated through cleaning, filters and heat, the robotic arm was given additional protection because it is the only spacecraft part that will directly touch the ice below the surface of Mars.

    Before the arm was heated, it was sealed in the biobarrier, which is made of a trademarked film called Tedlar that holds up to baking like a turkey-basting bag. This ensures that any new bacterial spores that might have appeared during the final steps before launch and during the journey to Mars will not contact the robotic arm.

    After Phoenix landed, springs were used to pop back the barrier, giving it room to deploy.

    These images were taken on May 25, 2008 and May 26, 2008 by the spacecraft's Surface Stereo Imager.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. Antibacterial Biomimetic Hybrid Films

    PubMed Central

    Ferrer, M. Carme Coll; Hickok, Noreen J.; Eckmann, David M.; Composto, Russell J.

    2012-01-01

    In this work, we present a novel method to prepare a hybrid coating based on dextran grafted to a substrate and embedded with silver nanoparticles (Ag NPs). First, the Ag NPs are synthesized in situ in the presence of oxidized dextran in solution. Second, the oxidized dextran is exposed to an amine functionalized surface resulting in the simultaneous grafting of dextran and the trapping of Ag NPs within the layer. The NP loading is controlled by the concentration of silver nitrate, which is 2 mM (DEX-Ag2) and 5 mM (DEX-Ag5). The dried film thickness increases with silver nitrate concentration from 2 nm for dextran to 7 nm and 12 nm for DEX-Ag2 and DEX-Ag5, respectively. The grafted dextran film displays features with a diameter and height of ~ 50 nm and 2 nm, respectively. For the DEX-Ag2 and DEX-Ag5, the dextran features as well as individual Ag NPs (~ 5 nm) and aggregates of Ag NPs are observed. Larger and more irregular aggregates are observed for DEX-Ag5. Overall, the Ag NPs are embedded in the dextran film as suggested by AFM and UVO studies. In terms of its antimicrobial activity, DEX-Ag2 resists bacterial adhesion to a greater extent than DEX-Ag5, which in turn is better than dextran and silicon. Because these antibacterial hybrid coatings can be grafted to a variety of surfaces, many biomedical applications can be envisioned, ranging from coating implants to catheters. PMID:23807896

  11. Radiation grafting on natural films

    NASA Astrophysics Data System (ADS)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

  12. Electrically conductive palladium-containing polyimide films

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; Furtsch, T. A.; Taylor, L. T.

    1981-01-01

    Palladium addition makes light, flexible film with low resistivity to relieve space charging. Polyimide film is prepared in four steps: preparation of polyamic acid in polar solvent; addition of soluable palladium complex salt; fabrication of film of "palladium polyamic acid" solution; and thermal imidization of film to palladium-containing polyimide by 300 C heating. Lowered resistivities were achieved without loss in film flexibility or increase in film weight.

  13. Turbine airfoil film cooling

    NASA Astrophysics Data System (ADS)

    Hylton, Larry D.

    1986-10-01

    Emphasis is placed on developing more accurate analytical models for predicting turbine airfoil external heat transfer rates. Performance goals of new engines require highly refined, accurate design tools to meet durability requirements. In order to obtain improvements in analytical capabilities, programs are required which focus on enhancing analytical techniques through verification of new models by comparison with relevant experimental data. The objectives of the current program are to develop an analytical approach, based on boundary layer theory, for predicting the effects of airfoil film cooling on downstream heat transfer rates and to verify the resulting analytical method by comparison of predictions with hot cascade data obtained under this program.

  14. Polycrystalline thin-films

    NASA Astrophysics Data System (ADS)

    Zweibel, K.; Mitchell, R.

    1986-02-01

    This annual report summarizes the status, accomplishments, and projected future research directions of the Polycrystalline Thin Film Task in the Photovoltaic Program Branch of the Solar Energy Research Institute's Solar Electric Research Division. Major subcontracted work in this area has concentrated on development of CuInSe2 and CdTe technologies. During FY 1985, major progress was achieved by subcontractors in: (1) developing a new, low-cost method of fabricating CuInSe2, and (2) improving the efficiency of CuInSe2 devices by about 10% (relative). The report also lists research planned to meet the Department of Energy's goals in these technologies.

  15. Thin film hydrogen sensor

    DOEpatents

    Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  16. Carbonaceous film coating

    DOEpatents

    Maya, Leon

    1989-01-01

    A method of making a carbonaceous film comprising heating tris(1,3,2-benzodiazaborolo)borazine or dodecahydro tris[1,3,2]diazaborine[1,2-a:1'2'-c:1"2"-e]borazine in an inert atmosphere in the presence of a substrate to a temperature at which the borazine compound decomposes, and the decomposition products deposit onto the substrate to form a thin, tenacious, highly reflective conductive coating having a narrow band gap which is susceptible of modification and a relatively low coefficient of friction.

  17. Liquid film demonstration experiment Skylab SL-4

    NASA Technical Reports Server (NTRS)

    Darbro, W.

    1975-01-01

    The liquid film demonstration experiment performed on Skylab 4 by Astronaut Gerald Carr, which involved the construction of water and soap films by boundary expansion and inertia, is discussed. Results include a 1-ml globule of water expanded into a 7-cm-diameter film as well as complex film structures produced by inertia whose lifetimes are longer in the low-g environment. Also discussed are 1-g acceleration experiments in which the unprovoked rupture of films was photographed and film lifetimes of stationary and rotated soap films were compared. Finally, there is a mathematical discussion regarding minimal surfaces, an isoperimetric problem, and liquid films.

  18. Predicting film genres with implicit ideals.

    PubMed

    Olney, Andrew McGregor

    2012-01-01

    We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories. PMID:23423823

  19. Fire resistant films for aircraft applications

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.

    1983-01-01

    Alternative sandwich panel decorative films were investigated as replacements for the polyvinyl fluoride currently used in aircraft interiors. Candidate films were studied for flammability, smoke emission, toxic gas emission, flame spread, and suitability as a printing surface for the decorative acrylic ink system. Several of the candidate films tested were flame modified polyvinyl fluoride, polyvinylidene fluoride, polyimide, polyamide, polysulfone, polyphenylsulfone, polyethersulfone, polybenzimidazole, polycarbonate, polyparabanic acid, polyphosphazene, polyetheretherketon, and polyester. The films were evaluated as pure films only, films silk-screened with an acrylic ink, and films adhered to a phenolic fiberglass substrate. Films which exhibited the highest fire resistant properties included PEEK polyetheretherketon, Aramid polyamide, and ISO-BPE polyester.

  20. Beryllium thin films for resistor applications

    NASA Technical Reports Server (NTRS)

    Fiet, O.

    1972-01-01

    Beryllium thin films have a protective oxidation resistant property at high temperature and high recrystallization temperature. However, the experimental film has very low temperature coefficient of resistance.

  1. Electrical initiation of an energetic nanolaminate film

    DOEpatents

    Tringe, Joseph W.; Gash, Alexander E.; Barbee, Jr., Troy W.

    2010-03-30

    A heating apparatus comprising an energetic nanolaminate film that produces heat when initiated, a power source that provides an electric current, and a control that initiates the energetic nanolaminate film by directing the electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature. Also a method of heating comprising providing an energetic nanolaminate film that produces heat when initiated, and initiating the energetic nanolaminate film by directing an electric current to the energetic nanolaminate film and joule heating the energetic nanolaminate film to an initiation temperature.

  2. Predicting Film Genres with Implicit Ideals

    PubMed Central

    Olney, Andrew McGregor

    2013-01-01

    We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories. PMID:23423823

  3. Metal oxide films on metal

    DOEpatents

    Wu, Xin D.; Tiwari, Prabhat

    1995-01-01

    A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

  4. Film Study: A Resource Guide.

    ERIC Educational Resources Information Center

    Manchel, Frank

    This resource guide describes six popular approaches to the study of the cinema and provides a practical analysis of selected books, materials, and information about motion picture rentals. Highlighting this extensive survey of film studies are the annotated, critical bibliographies and filmographies of significant books, articles and films by and…

  5. Film Library Information Management System.

    ERIC Educational Resources Information Center

    Minnella, C. Vincent; And Others

    The computer program described not only allows the user to determine rental sources for a particular film title quickly, but also to select the least expensive of the sources. This program developed at SUNY Cortland's Sperry Learning Resources Center and Computer Center is designed to maintain accurate data on rental and purchase films in both…

  6. Symbolism in the Feature Film.

    ERIC Educational Resources Information Center

    Bakony, Edward

    A study of symbolism in feature films reveals how the symbolism employed by film makers can serve as a bridge between feeling and thought, and between aesthetics and cognition. What individuals read from and learn through a symbol varies with what they bring to it. The filmmaker's symbolims must be universal and not private. However, symbolism in…

  7. Thin film atomic hydrogen detectors

    NASA Technical Reports Server (NTRS)

    Gruber, C. L.

    1977-01-01

    Thin film and bead thermistor atomic surface recombination hydrogen detectors were investigated both experimentally and theoretically. Devices were constructed on a thin Mylar film substrate. Using suitable Wheatstone bridge techniques sensitivities of 80 microvolts/2x10 to the 13th power atoms/sec are attainable with response time constants on the order of 5 seconds.

  8. Film coatings for contoured surfaces

    NASA Technical Reports Server (NTRS)

    Flanery, H. E.; Frost, R. K.; Olson, A. J.

    1981-01-01

    Thickness of fluorocarbon elastomer films applied in contoured shapes by vacuum forming is difficult to control at sharply curved areas. Process for spraying contoured fluorocarbon elastomer films of uniform strength and thickness has been used instead of vacuum forming to fabricate curtain covering external tank of Space Shuttle. Conventional spray equipment may be used.

  9. Uses for Free Film Cans

    ERIC Educational Resources Information Center

    Batoff, Mitchell E.; Harmen, Jerry

    1973-01-01

    Describes multiple uses of empty film cans for equipping an elementary school science classroom. Instructional units in which film cans may be useful include buoyancy, mobiles, growing seeds, peas and particles, rocks and minerals, structures, field studies, sound, balancing, electricity, pedulums, chemical change, and optics, light, color. (PS)

  10. The Thin Oil Film Equation

    NASA Technical Reports Server (NTRS)

    Brown, James L.; Naughton, Jonathan W.

    1999-01-01

    A thin film of oil on a surface responds primarily to the wall shear stress generated on that surface by a three-dimensional flow. The oil film is also subject to wall pressure gradients, surface tension effects and gravity. The partial differential equation governing the oil film flow is shown to be related to Burgers' equation. Analytical and numerical methods for solving the thin oil film equation are presented. A direct numerical solver is developed where the wall shear stress variation on the surface is known and which solves for the oil film thickness spatial and time variation on the surface. An inverse numerical solver is also developed where the oil film thickness spatial variation over the surface at two discrete times is known and which solves for the wall shear stress variation over the test surface. A One-Time-Level inverse solver is also demonstrated. The inverse numerical solver provides a mathematically rigorous basis for an improved form of a wall shear stress instrument suitable for application to complex three-dimensional flows. To demonstrate the complexity of flows for which these oil film methods are now suitable, extensive examination is accomplished for these analytical and numerical methods as applied to a thin oil film in the vicinity of a three-dimensional saddle of separation.

  11. Polysilicon thin films and interfaces

    SciTech Connect

    Kamins, T. ); Raicu, B. ); Thompson, C.V. )

    1990-01-01

    This volume contains the proceedings of a symposium on polysilicon thin films and interfaces, held as part of the 1990 Materials Research Society Spring Meeting. Topics covered include: crystal grown fo silicon and germanium wafers for photovoltaic devices, microanalysis of tungsten silicide interface, thermal processing of polysilicon thin films, and electrical and optical properties of polysilicon sheets for photovoltaic devices.

  12. Black Male Images in Films

    ERIC Educational Resources Information Center

    Ward, Francis

    1974-01-01

    Argues that the "super" image of the black male in films served three essential purposes: it gave blacks whatever therapy they needed from films; it had hot box office appeal; and it kept white in control of the images blacks have had of themselves. (Author/JM)

  13. Nonfiction Film; A Critical History.

    ERIC Educational Resources Information Center

    Barsam, Richard Meran

    In this survey history of the documentary or nonfiction cinema, major emphasis is placed upon John Grierson and the British documentary movement as exemplary of the factual films with goals of social improvement and on Robert Flaherty, whose movement stressed poetic or humanistic nonfiction film treatment. Newsreels and current trends in…

  14. The Public Library Film Redefined.

    ERIC Educational Resources Information Center

    Peltier, Euclid

    1978-01-01

    An historical discussion of three types of film--teaching, information, and entertainment--is presented. The numbers of films in each category, especially the last, which includes the animated, unnarrated, iconographic, underground, and avant-garde, has grown substantially. Libraries have quickly accepted all except the revolutionary philosophies…

  15. Drug Abuse Films, Second Edition.

    ERIC Educational Resources Information Center

    National Coordinating Council on Drug Education, Washington, DC.

    This second edition updates and expands a 1971 evaluation of films and audiovisuals related to drug education performed by the National Coordinating Council on Drug Education. Materials in this edition are evaluated both for accuracy and effectiveness as a communications tool. They are separated into two sections--films and other audiovisuals…

  16. Evaluation of Agfacontour professional film

    NASA Technical Reports Server (NTRS)

    Goodding, R. A.

    1972-01-01

    The results obtained by the Photo Science Office in the evaluation of Agfacontour Professional Film are presented. The feasibility of utilizing this film in the evaluation of aerial or extraterrestrial imagery has been investigated. Sensitometric properties have been determined, and optimum handling techniques have been identified in an attempt to facilitate better use of the material.

  17. Films and the English Class.

    ERIC Educational Resources Information Center

    Donelson, Kenneth, Ed.

    1971-01-01

    The importance of film in the English classroom and its vitality in the English curriculum are discussed. Articles that comprise this issue of the bulletin are: The Trouble with Film Teaching by James E. Cutts; "You Ain't Heard Nothin' Yet" or Send Your Students to the Flicks Tonight by Bob Haskett; It's the Reel Thing: The Verite of Cinema Is…

  18. Teaching the Holocaust through Film.

    ERIC Educational Resources Information Center

    Michalczyk, John J.

    The use of Holocaust-related films and Holocaust survivors as classroom resources is analyzed. The perspective and function of four film genres are outlined as follows. Newsreels, made by the Nazis to chronicle their "progress," provide powerful raw footage of the concentration camp experience. Documentaries, generally made by Allied sources after…

  19. Pectin films for various applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article presents 4 examples of new uses of pectin films: (I) edible pectin and protein films as packaging or coating materials; (II) pectin and poly(lactic acid) composites for antimicrobial packaging, (III) moisture-sensitive pectin-sponges for the controlled release of chlorine dioxide; and (...

  20. Laser refractometry of edible films

    NASA Astrophysics Data System (ADS)

    Panchev, I.; Nikolova, K.; Sainov, Simeon C.

    2004-06-01

    Refraction index of edible films from polysaccharides (pectin, xanthan, carboxy-methyl-cellulose, polymixan) has been investigated using laser microrefractomeeter, constructed by the authors. Experimental data about the optical density and the thickness of the edible films have been obtained. The results from the investigation can be used in the development of new packing technologies for food products.

  1. Liquid-film electron stripper

    DOEpatents

    Gavin, Basil F.

    1986-01-01

    An improved liquid-film electron stripper particularly for high intensity heavy ion beams which produces constant regenerated, stable, free-standing liquid films having an adjustable thickness between 0.3 to 0.05 microns. The improved electron stripper is basically composed of at least one high speed, rotating disc with a very sharp, precision-like, ground edge on one said of the disc's periphery and with a highly polished, flat, radial surface adjacent the sharp edge. A fine stream of liquid, such as oil, impinges at a 90.degree. angle adjacent the disc's sharp outer edge. Film terminators, located at a selected distance from the disc perimeter are positioned approximately perpendicular to the film. The terminators support, shape, and stretch the film and are arranged to assist in the prevention of liquid droplet formation by directing the collected film to a reservoir below without breaking or interfering with the film. One embodiment utilizes two rotating discs and associated terminators, with the discs rotating so as to form films in opposite directions, and with the second disc being located down beam-line relative to the first disc.

  2. Feminist Film Theory and Criticism.

    ERIC Educational Resources Information Center

    Mayne, Judith

    1985-01-01

    Discusses Laura Mulvey's 1975 essay, "Visual Pleasure and Narrative Cinema," and the ideas about feminist film theory and psychoanalysis as a critical tool which it raises. Suggests contradiction is the central issue in feminist film theory. Explores definitions of women's cinema. (SA)

  3. Latino Film and Video Images.

    ERIC Educational Resources Information Center

    Vazquez, Blanca, Ed.

    1990-01-01

    This theme issue of the "Centro Bulletin" examines media stereotypes of Latinos and presents examples of alternatives. "From Assimilation to Annihilation: Puerto Rican Images in U.S. Films" (R. Perez) traces the representation of Puerto Ricans from the early days of television to the films of the 1970s. "The Latino 'Boom' in Hollywood" (C. Fusco)…

  4. Thin film ion conducting coating

    DOEpatents

    Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  5. Teaching Film Animation to Children.

    ERIC Educational Resources Information Center

    Andersen, Yvonne

    Under the author's direction, students from 5 to 18 years old have been making prize-winning animated films. In this guide intended for any adult who wishes to teach film animation, she describes and illustrates the techniques she has developed in her seven years of experience teaching animation to children in a workshop setting. All essential…

  6. System for measuring film thickness

    DOEpatents

    Batishko, Charles R.; Kirihara, Leslie J.; Peters, Timothy J.; Rasmussen, Donald E.

    1990-01-01

    A system for determining the thicknesses of thin films of materials exhibiting fluorescence in response to exposure to excitation energy from a suitable source of such energy. A section of film is illuminated with a fixed level of excitation energy from a source such as an argon ion laser emitting blue-green light. The amount of fluorescent light produced by the film over a limited area within the section so illuminated is then measured using a detector such as a photomultiplier tube. Since the amount of fluorescent light produced is a function of the thicknesses of thin films, the thickness of a specific film can be determined by comparing the intensity of fluorescent light produced by this film with the intensity of light produced by similar films of known thicknesses in response to the same amount of excitation energy. The preferred embodiment of the invention uses fiber optic probes in measuring the thicknesses of oil films on the operational components of machinery which are ordinarily obscured from view.

  7. Soap film gas flowmeter

    SciTech Connect

    Lalin, H.S.; Bermudez, J.E.; Fleming, W.T.

    1987-09-08

    A soap film gas flowmeter is described comprising: a flow tube having a hollow body with opposite open ends through which a soap film is propelled and a first closed chamber housing a soap solution. It also includes means for supporting the flow tube in a substantially vertical position with the open bottom end of the flow tube disposed in the first chamber above the soap solution; a second closed chamber into which the open top end of the flow tube extends and gas inlet means for introducing gas into the first chamber at a flow rate to be measured using the flowmeters. A gas exit means is included for discharging the gas introduced into the first chamber through the second chamber. Plus there are means for generating a single soap bubble from the soap solution substantially at the bottom end of the flow tube and a relatively large opening in the flowtube for providing an open passageway for inlet gas to pass through the flowtube when the bottom open end of the flowtube is covered by the soap solution.

  8. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Pohl, P.I.; Brinker, C.J.

    1997-04-01

    Separating light gases using membranes is a technology area for which there exists opportunities for significant energy savings. Examples of industrial needs for gas separation include hydrogen recovery, natural gas purification, and dehydration. A membrane capable of separating H{sub 2} from other gases at high temperatures could recover hydrogen from refinery waste streams, and facilitate catalytic dehydrogenation and the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction. Natural gas purification requires separating CH{sub 4} from mixtures with CO{sub 2}, H{sub 2}S, H{sub 2}O, and higher alkanes. A dehydrating membrane would remove water vapor from gas streams in which water is a byproduct or a contaminant, such as refrigeration systems. Molecular sieve films offer the possibility of performing separations involving hydrogen, natural gas constituents, and water vapor at elevated temperatures with very high separation factors. It is in applications such as these that the authors expect inorganic molecular sieve membranes to compete most effectively with current gas separation technologies. Cryogenic separations are very energy intensive. Polymer membranes do not have the thermal stability appropriate for high temperature hydrogen recovery, and tend to swell in the presence of hydrocarbon natural gas constituents. The authors goal is to develop a family of microporous oxide films that offer permeability and selectivity exceeding those of polymer membranes, allowing gas membranes to compete with cryogenic and adsorption technologies for large-scale gas separation applications.

  9. Film Fabrication Technologies at NREL

    NASA Technical Reports Server (NTRS)

    Mcconnell, Robert D.

    1993-01-01

    The National Renewable Energy Laboratory (NREL) has extensive capabilities for fabricating a variety of high-technology films. Much of the in-house work in NREL's large photovoltaics (PV) program involves the fabrication of multiple thin-film semiconducting layers constituting a thin-film PV device. NREL's smaller program in superconductivity focuses on the fabrication of superconducting films on long, flexible tape substrates. This paper focuses on four of NREL's in-house research groups and their film fabrication techniques, developed for a variety of elements, alloys, and compounds to be deposited on a variety of substrates. As is the case for many national laboratories, NREL's technology transfer efforts are focusing on Cooperative Research and Development Agreements (CRADA's) between NREL researchers and private industry researchers.

  10. Anode film formation and control

    DOEpatents

    Koski, Oscar; Marschman, Steven C.

    1990-01-01

    A protective film is created about the anode within a cryolite-based electrolyte during electrolytic production of aluminum from alumina. The film function to minimize corrosion of the anode by the cryolitic electrolyte and thereby extend the life of the anode. Various operating parameters of the electrolytic process are controlled to maintain the protective film about the anode in a protective state throughout the electrolytic reduction of alumina. Such parameters include electrolyte temperature, electrolyte ratio, current density, and Al.sub.2 O.sub.3 concentration. An apparatus is also disclosed to enable identification of the onset of anode corrosion due to disruption of the film to provide real time information regarding the state of the film.

  11. Anode film formation and control

    DOEpatents

    Koski, O.; Marschman, S.C.

    1990-05-01

    A protective film is created about the anode within a cryolite-based electrolyte during electrolytic production of aluminum from alumina. The film functions to minimize corrosion of the anode by the cryolitic electrolyte and thereby extend the life of the anode. Various operating parameters of the electrolytic process are controlled to maintain the protective film about the anode in a protective state throughout the electrolytic reduction of alumina. Such parameters include electrolyte temperature, electrolyte ratio, current density, and Al[sub 2]O[sub 3] concentration. An apparatus is also disclosed to enable identification of the onset of anode corrosion due to disruption of the film to provide real time information regarding the state of the film. 3 figs.

  12. Laser damage threshold of diamond films

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia; Cropper, Andre D.; Watkins, Linwood C.; Byvik, Charles E.; Buoncristiani, A. Martin

    1989-01-01

    The possibility that diamond films may inhibit laser-induced damage to optical components in laser systems films was investigated by measuring laser damage thresholds of free-standing diamond film windows, diamond films deposited on silicon substrates, and bare silicon substrate. Polycrystalline diamond films were deposited using a dc plasma-enhanced CVD process. It was found that free-standing diamond films had the highest laser damage threshold at 1064 nm. For a diamond film of 630 nm, the damage threshold was found to be 7 J/sq cm, as compared to a damage threshold of 4.5 J/sq cm for bare silicon, and a low value of 1.5 J/sq cm for the film/substrate combination. The damage mechanism is considered to involve melting or dielectric breakdown induced by laser radiation. The low value of the film/substrate combination is attributed to film stress and conditions of film deposition.

  13. Laser damage threshold of diamond films

    NASA Astrophysics Data System (ADS)

    Albin, Sacharia; Cropper, Andre D.; Watkins, Linwood C.; Byvik, Charles E.; Buoncristiani, A. Martin

    1989-03-01

    The possibility that diamond films may inhibit laser-induced damage to optical components in laser systems films was investigated by measuring laser damage thresholds of free-standing diamond film windows, diamond films deposited on silicon substrates, and bare silicon substrate. Polycrystalline diamond films were deposited using a dc plasma-enhanced CVD process. It was found that free-standing diamond films had the highest laser damage threshold at 1064 nm. For a diamond film of 630 nm, the damage threshold was found to be 7 J/sq cm, as compared to a damage threshold of 4.5 J/sq cm for bare silicon, and a low value of 1.5 J/sq cm for the film/substrate combination. The damage mechanism is considered to involve melting or dielectric breakdown induced by laser radiation. The low value of the film/substrate combination is attributed to film stress and conditions of film deposition.

  14. Oriented lead zirconate titanate thin films: Characterization of film crystallization

    SciTech Connect

    Voigt, J.A.; Tuttle, B.A.; Headley, T.J.; Eatough, M.O.; Lamppa, D.L.; Goodnow, D.

    1993-11-01

    Film processing temperature and time was varied to characterize the pyrochlore-to-perovskite crystallization of solution-derived PZT 20/80 thin films. 3000 {Angstrom} thick films were prepared by spin deposition using <100> single crystal MgO as substrate. By controlled rapid thermal processing, films at different stages in the perovskite crystallization process were prepared with the tetragonal PZT 20/80 phase being <100>/<001> oriented relative to the MgO surface. An activation energy for the conversion process of 326 kJ/mole was determined by use of an Arrhenius expression using rate constants found by application of the method of Avrami. Activation energy for formation of the PZT 20/80 perovskite phase of the solution-derived films compared favorably with that calculated from data by Kwok and Desu for sputter-deposited 3500 {Angstrom} thick PZT 55/45 films. Similarity in activation energies indicates that the energetics of the conversion process are not strongly dependent on the method used for film deposition.

  15. Flow fields in soap films: Relating viscosity and film thickness

    NASA Astrophysics Data System (ADS)

    Prasad, V.; Weeks, Eric R.

    2009-08-01

    We follow the diffusive motion of colloidal particles in soap films with varying h/d , where h is the thickness of the film and d is the diameter of the particles. The hydrodynamics of these films are determined by looking at the correlated motion of pairs of particles as a function of separation R . The Trapeznikov approximation [A. A. Trapeznikov, Proceedings of the 2nd International Congress on Surface Activity (Butterworths, London, 1957), p. 242] is used to model soap films as an effective two-dimensional (2D) fluid in contact with bulk air phases. The flow fields determined from correlated particle motions show excellent agreement with what is expected for the theory of 2D fluids for all our films where 0.6≤h/d≤14.3 , with the 2D shear viscosity matching that predicted by Trapeznikov. However, the parameters of these flow fields change markedly for thick films (h/d>7±3) . Our results indicate that three-dimensional effects become important for these thicker films, despite the flow fields still having a 2D character.

  16. Electrochromism in nickel oxide films

    SciTech Connect

    Wruck, D.A.

    1991-01-01

    Optical absorption in a thin-film nickel oxide electrode depends on the state of charge of the electrode; the effect has been called electrochromism, and it may have practical applications in low-speed light modulation devices. In this dissertation, the physical and chemical processes which lead to the change in optical properties are investigated. Preparation of NiO film electrodes by reactive sputtering of a Ni target in an Ar + O[sub 2] gas mixture is described, and the electrochromic response is correlated to film growth conditions. Structural, electronic, and electrochemical properties of the NiO films are characterized by x-ray diffraction, infrared absorption, x-ray photoemission, optical absorption, electrical conductivity, and electrochemical measurements. It is proposed that the electrochromism results from the adsorption and desorption of protons at the oxygen-rich surface of a granular and porous NiO film. The surface electronic levels are then modified by the presence or absence of the O-H bonds, and the effect on the film electronic properties is discussed. A general discussion is also given of the current-limiting processes at the NiO film electrodes.

  17. Calorimetry of epitaxial thin films.

    PubMed

    Cooke, David W; Hellman, F; Groves, J R; Clemens, B M; Moyerman, S; Fullerton, E E

    2011-02-01

    Thin film growth allows for the manipulation of material on the nanoscale, making possible the creation of metastable phases not seen in the bulk. Heat capacity provides a direct way of measuring thermodynamic properties of these new materials, but traditional bulk calorimetric techniques are inappropriate for such a small amount of material. Microcalorimetry and nanocalorimetry techniques exist for the measurements of thin films but rely on an amorphous membrane platform, limiting the types of films which can be measured. In the current work, ion-beam-assisted deposition is used to provide a biaxially oriented MgO template on a suspended membrane microcalorimeter in order to measure the specific heat of epitaxial thin films. Synchrotron x-ray diffraction showed the biaxial order of the MgO template. X-ray diffraction was also used to prove the high quality of epitaxy of a film grown onto this MgO template. The contribution of the MgO layer to the total heat capacity was measured to be just 6.5% of the total addenda contribution. The heat capacity of a Fe(.49)Rh(.51) film grown epitaxially onto the device was measured, comparing favorably to literature data on bulk crystals. This shows the viability of the MgO∕SiN(x)-membrane-based microcalorimeter as a way of measuring the thermodynamic properties of epitaxial thin films. PMID:21361612

  18. (Thin films under chemical stress)

    SciTech Connect

    Not Available

    1990-01-01

    As stated above the purpose of this research is to enable workers in a variety of fields to understand the chemical and physical changes which take place when thin films (primarily organic films) are placed under chemical stress. This stress may occur because the film is being swelled by penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). These questions are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers, which might have unique functional properties. In the past year we have concentrated on the following objectives: (1) understanding how the two possible diffusion mechanisms contribute to the swelling of thin films of organic polymers place in solution, (2) identifying systems which are appropriate polymer media for the construction of composite membranes for use in aqueous environments, and (3) understanding the self-assembly process for long chain fatty acids at model surfaces. Progress in meeting each of these objectives will be described in this report. 4 figs.

  19. Improving analysis of radiochromic films

    NASA Astrophysics Data System (ADS)

    Baptista Neto, A. T.; Meira-Belo, L. C.; Faria, L. O.

    2014-02-01

    An appropriate radiochromic film should respond uniformly throughout its surface after exposure to a uniform radiation field. The evaluation of radiochromic films may be carried out, for example, by measuring color intensities in film-based digitized images. Fluctuations in color intensity may be caused by many different factors such as optical structure of the film's active layer, defects in structure of the film, scratches and external agents, such as dust. The use of high spatial resolution during film scanning should also increase microscopic uniformity. Since the average is strongly influenced by extreme values, the use of other statistical tools, for which this problem becomes inconspicuous, optimizes the application of higher spatial resolution as well as reduces standard deviations. This paper compares the calibration curves of the XR-QA2 Gafchromic® radiochromic film based on three different methods: the average of all color intensity readings, the median of these same readings and the average of readings that fall between the first and third quartiles. Results indicate that a higher spatial resolution may be adopted whenever the calibration curve is based on tools less influenced by extreme values such as those generated by the factors mentioned above.

  20. Precursor films in wetting phenomena.

    PubMed

    Popescu, M N; Oshanin, G; Dietrich, S; Cazabat, A-M

    2012-06-20

    The spontaneous spreading of non-volatile liquid droplets on solid substrates poses a classic problem in the context of wetting phenomena. It is well known that the spreading of a macroscopic droplet is in many cases accompanied by a thin film of macroscopic lateral extent, the so-called precursor film, which emanates from the three-phase contact line region and spreads ahead of the latter with a much higher speed. Such films have been usually associated with liquid-on-solid systems, but in the last decade similar films have been reported to occur in solid-on-solid systems. While the situations in which the thickness of such films is of mesoscopic size are fairly well understood, an intriguing and yet to be fully understood aspect is the spreading of microscopic, i.e. molecularly thin, films. Here we review the available experimental observations of such films in various liquid-on-solid and solid-on-solid systems, as well as the corresponding theoretical models and studies aimed at understanding their formation and spreading dynamics. Recent developments and perspectives for future research are discussed. PMID:22627067