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Sample records for 111-oriented bfo films

  1. 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.

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

    DOE PAGES

    Si, W.; Zhang, C.; Wu, L.; ...

    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

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

    PubMed

    Jo, Seo-Hyeon; Lee, Sung-Gap; Lee, Young-Hie

    2012-01-05

    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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Equilateral triangular ferroelectric closure domains in (111)-oriented epitaxial Pb(Zr,Ti)O3 thin films

    NASA Astrophysics Data System (ADS)

    Yang, Sang Mo; Shin, Y. J.; Noh, T. W.; Ehara, Y.; Funakubo, H.; Yoon, J.-G.; Scott, J. F.

    2013-03-01

    Over 60 years ago, Charles Kittel predicted that intriguing quadrant flux-closure domains could spontaneously form in small ferromagnetic platelets. Such quadrant flux-closure domains are considered as a precursor for the true vortex states, having attracted particular interest for storing memory devices. Although the vortex states are now ubiquitous and rather well understood in ferromagnets, even the flux-closure domains as their precursors are much less established in ferroelectrics (FEs). Here we report the generation of novel equilateral triangular FE closure domains. We generated such intriguing states by using the high crystalline anisotropy energy of a (111)-oriented epitaxial PbZr0.35Ti0.65O3 thin film. Vector piezoresponse force microscopy analysis showed clearly the equilateral triangular closure states, consisting of three stripe domain bundles with three 120 degree orientation differences. Interestingly, the observed two closure states had the different rotation direction around the core, i.e., clockwise and anti-clockwise.

  10. Shift of morphotropic phase boundary in high-performance [111]-oriented epitaxial Pb (Zr, Ti) O3 thin films

    NASA Astrophysics Data System (ADS)

    Yu, Qi; Li, Jing-Feng; Zhu, Zhi-Xiang; Xu, Ying; Wang, Qing-Ming

    2012-07-01

    High-performance epitaxial niobium-doped lead zirconate titanate thin films [Pb(ZrxTi1-x)0.98Nb0.02O3] with a fixed thickness were deposited on [111]-cut single-crystalline SrTiO3 substrates by a sol-gel process as a function of Zr/Ti ratio ranging from 20/80 to 80/20. An obvious shift of morphotropic phase boundary (MPB) was observed in the [111]-oriented epitaxial films. Deviating from the Zr/Ti ratio of 52/48 in bulk materials, the MPB composition in the as-deposited films was found to move to a lower Zr/Ti ratio between 30/70 and 40/60, which agrees with the theoretical analysis on the basis of lattice mismatch between films and substrates and is further confirmed by the XRD patterns and Raman spectrum as well as ferroelectric test. Furthermore, a superior remnant polarization (Pr) value among all the compositions was obtained at a Zr/Ti ratio of 30/70, indicating that the extrinsic ferroelectric polarization near the new morphotropic phase boundary will lead to outstanding dielectric and piezoelectric performance in the epitaxial PZT thin film system.

  11. The Evidence of Giant Surface Flexoelectric Field in (111) Oriented BiFeO3 Thin Film.

    PubMed

    Yang, Tieying; Zhang, Xingmin; Chen, Bin; Guo, Haizhong; Jin, Kuijuan; Wu, Xiaoshan; Gao, Xingyu; Li, Zhong; Wang, Can; Li, Xiaolong

    2017-02-15

    In this work, the surface structure of a single-domain epitaxial BiFeO3 film with (111) orientation was investigated by in situ grazing incidence X-ray diffraction and X-ray reflectivity. We found that a large strain gradient exists in the surface region (2-3 nm) of the BiFeO3 film. The strain gradient is approximately 10(7) m(-1), which is 2 or 3 orders of magnitude larger than the value inside the film. Moreover, we found that a surface layer with a lower electron density compared with the underlying BiFeO3 layer exists on the surface of BiFeO3 film, and this layer exhibits an irreversible surface structure transition occurs at 500 K, which should be associated with the surface flexoelectric field. We considered that this large strain gradient is originated from the surface depolarization field of ferroelectrics. Our results suggest a coupling between the surface structure and the flexoelectricity and imply that the surface layer and properties would be controlled by the strain gradient in ferroelectric films.

  12. Growth of (111)-oriented epitaxial and textured ferroelectric Y-doped HfO2 films for downscaled devices

    NASA Astrophysics Data System (ADS)

    Katayama, Kiliha; Shimizu, Takao; Sakata, Osami; Shiraishi, Takahisa; Nakamura, Syogo; Kiguchi, Takanori; Akama, Akihiro; Konno, Toyohiko J.; Uchida, Hiroshi; Funakubo, Hiroshi

    2016-09-01

    In this study, the growth of (111)-oriented epitaxial and textured YO1.5-HfO2 (0.07:0.93 ratio) films using the pulsed laser deposition method is presented. Epitaxial films were prepared on ITO//(111)yttria-stabilized zirconia (YSZ) substrates (ITO: Sn-doped In2O3; YSZ: yttria-stabilized zirconia), while textured films were prepared on (111)Pt/TiOx/SiO2//Si substrates with and without an ITO buffer layer via the grain on grain coherent growth. Inserting an ITO layer increased the volume fraction of the ferroelectric orthorhombic phase. Both the epitaxial and uniaxially textured films exhibited similar ferroelectricity with a remanent polarization of around 10 μC/cm2 and a coercive field of 1.9 to 2.0 MV/cm. These results present us with a way of obtaining stable and uniform ferroelectric properties for each grain and device cells consisting of a small number of grains. This opens the door for ultimately miniaturized ferroelectric devices, such as ferroelectric field effect transistors with small gate length and resistive random access memory using ferroelectric tunnel junctions.

  13. Laser beam scanning microscope and piezoresponse force microscope studies on domain structured in 001-, 110-, and 111-oriented NaNbO3 films

    NASA Astrophysics Data System (ADS)

    Yamazoe, Seiji; Kohori, Akihiro; Sakurai, Hiroyuki; Kitanaka, Yuuki; Noguchi, Yuji; Miyayama, Masaru; Wada, Takahiro

    2012-09-01

    NaNbO3 (NN) films were epitaxially grown on SrRuO3/(001), (110), and (111)SrTiO3 substrates, and these NN films were characterized by a laser beam scanning microscope and a piezoresponse force microscope. The 001-oriented NN film had antiferroelectric 90° domains with 100 and 010 polarization axes and 90° domain walls exhibiting piezoresponse. The piezoresponding domain walls would be induced by ferroelasticity. On the other hand, the 110- and 111-oriented NN films possessed 60° domains. The 60° domains of 110-oriented NN film were constructed by antiferroelectric 11¯0 domain and piezoresponding {101} and {011} domains. In the case of 111-oriented NN, three kinds of 60° domains (11¯0 and 01¯1, 01¯1 and 101¯, and 101¯ and 11¯0) were observed. The fine domains with piezoresponse were also observed in the mixed region with the three 60° domains. From the stress measurement, we found that the difference in the domain structure of 001-, 110-, and 111-oriented NN films depends not only on the orientation direction but also on the stress from the substrate. Moreover, the stress and the induction of the piezoelectric domain also influence the dielectric behavior.

  14. 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.

  15. Effect of Misfit Strain on Pyroelectric Properties of (111) Oriented Pb(Zr1-x Ti x ) O3 Thin Films

    NASA Astrophysics Data System (ADS)

    Qiu, Jian-Hua; Chen, Zhi-Hui; Wang, Xiu-Qin; Yuan, Ning-Yi; Ding, Jian-Ning

    2016-10-01

    Based on the Landau-Dovenshire theory, the thermodynamic potential of (111) oriented films is constructed to investigate the pyroelectric properties of Pb(Zr1-xTix) O3 thin films. Due to the presence of nonlinear coupling terms resulted from the (111) epitaxy with substrates, the effects of misfit strain and electric field on the phase transitions at room temperature are more complex than that of (001) and (110) oriented films. Pb(Zr0.5Ti0.5) O3 thin films with the Ti composition around the morphotropic phase boundary (MPB) have the giant dielectric and pyroelectric properties. Moreover, Pb(Zn1-xTix) O3 thin films grown on the tensile substrates which induce the triclinic γ phase have the larger dielectric and pyroelectric properties than that on the compressive substrates. Therefore, the physical properties of (111) oriented Pb(Zr1-xTix) O3 thin films can be adjusted by choosing the suitable substrates. Supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions, the research fund of Jiangsu Province Cultivation base for State Key Laboratory of Photovoltaic Science and Technology, Major Projects of Natural Science Research in Jiangsu Province under Grant Nos. 15KJA43002, 16KJD430006, and also sponsored by Qing Lan Project of Education Department of Jiangsu Province

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

    DOE PAGES

    Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; ...

    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

  17. 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.

  18. 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.

  19. 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.

  20. Large Energy Storage Density and High Thermal Stability in a Highly Textured (111)-Oriented Pb0.8Ba0.2ZrO3 Relaxor Thin Film with the Coexistence of Antiferroelectric and Ferroelectric Phases.

    PubMed

    Peng, Biaolin; Zhang, Qi; Li, Xing; Sun, Tieyu; Fan, Huiqing; Ke, Shanming; Ye, Mao; Wang, Yu; Lu, Wei; Niu, Hanben; Zeng, Xierong; Huang, Haitao

    2015-06-24

    A highly textured (111)-oriented Pb0.8Ba0.2ZrO3 (PBZ) relaxor thin film with the coexistence of antiferroelectric (AFE) and ferroelectric (FE) phases was prepared on a Pt/TiOx/SiO2/Si(100) substrate by using a sol-gel method. A large recoverable energy storage density of 40.18 J/cm(3) along with an efficiency of 64.1% was achieved at room temperature. Over a wide temperature range of 250 K (from room temperature to 523 K), the variation of the energy density is within 5%, indicating a high thermal stability. The high energy storage performance was endowed by a large dielectric breakdown strength, great relaxor dispersion, highly textured orientation, and the coexistence of FE and AFE phases. The PBZ thin film is believed to be an attractive material for applications in energy storage systems over a wide temperature range.

  1. Polarized Raman scattering of multiferroic BiFeO3 epitaxial films with rhombohedral R3c symmetry

    NASA Astrophysics Data System (ADS)

    Singh, Manoj K.; Jang, Hyun M.; Ryu, Sangwoo; Jo, Moon-Ho

    2006-01-01

    Highly (111)-oriented rhombohedral BiFeO3 (BFO) thin films were grown on (111) SrTiO3 substrates by pulsed laser deposition. Polarized Raman-scattering study of the (111)-oriented epitaxial BFO thin film with rhombohedral R3c symmetry was carried out by employing two distinct backscattering geometries. The A1-symmetry transverse-optical [A1(TO )] phonons were selectively isolated from the E-symmetry transverse-optical [E(TO)] phonons by employing Y'(ZZ)Y' polarization configuration in a novel side-view backscattering. By comparing the Y'(ZZ)Y' spectrum with the Z(X 'X')Z polarization spectrum in a normal backscattering, we were able to assign most of A1 and E-symmetry normal modes of R3c BFO. In addition, we found that there was a negligible LO-TO splitting in the A1-symmetry normal modes.

  2. 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.

  3. Roles of L10 ordering in controlling the magnetic anisotropy and coercivity of (111)-oriented CoPt ultrathin continuous layers in CoPt/AlN multilayer films

    NASA Astrophysics Data System (ADS)

    Cai, Wupeng; Shi, Ji; Nakamura, Yoshio; Liu, Wei; Yu, Ronghai

    2011-10-01

    Chemical ordering of (111)-oriented CoPt ultrathin continuous layers in CoPt/AlN multilayer structure has been investigated. It is found that upon thermal annealing at 600 °C, CoPt layers undergo ordering transformation even when the CoPt layers are as thin as 2 nm. The degree of ordering increases with increasing the layer thickness. For the 600 °C annealed CoPt/AlN multilayer film with 2 nm thick CoPt layers, due to the ordering, out-of-plane coercivity is increased to 3330 Oe, while large perpendicular magnetic anisotropy constant of 8.1 × 106 erg/cm3 is exhibited. These coercivity and anisotropy energy are appropriate for the practical use as magnetic recording media. It is clear that for such a structure, ordering transformation does not impair the perpendicular magnetic anisotropy induced by the interface and magnetoelastic effects. The easy axis of magnetization still lies in the layer normal direction, i.e., [111] direction, although for L10 structure it is supposed to lie in the [001] direction. But L10 ordering does contribute to the enhancement of coercivity.

  4. 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.

  5. 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.

  6. Piezoresistive effect of n-type <111>-oriented Si nanowires under large tension/compression

    NASA Astrophysics Data System (ADS)

    Gao, Di; Yang, Zhenyu; Zheng, Lingli; Zheng, Kun

    2017-03-01

    Small-scale samples enable us to understand changes in physical properties under larger strain due to their higher tolerance to deformation. In this study, the piezoresistive character of n-type <111>-oriented Si nanowires under large strain was measured during tensile and compressive deformations. The Si nanowires were directly cut from the wafer using top-down technology and deformed while capturing their electrical properties inside a transmission electron microscope. The experimental results show that both tensile and compressive deformation enhanced their electrical transport properties. The piezoresistance coefficient is of the same order of magnitude as its bulk counterpart, but half as large, which may be attributed to a larger strain magnitude. We also studied the circulatory characteristics and influence of electron beam radiation. This study provided new physical insights into piezoresistive effects under large strain.

  7. Symmetry-adapted calculations of strain and polarization fields in (111)-oriented zinc-blende quantum dots

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Caro, M. A.; O'Reilly, E. P.; Marquardt, O.

    2011-09-01

    We present expressions for the elastic and first-order piezoelectric tensor in (111)-oriented III-V zinc-blende semiconductors. Moreover, an equation for the second-order piezoelectric polarization vector in these systems is derived. Together these expressions provide an efficient route to calculate built-in potentials and strain fields in (111)-oriented zinc-blende nanostructures. Our detailed analysis provides insight into the key parameters that modify strain and built-in fields in a (111)-oriented zinc-blende system compared to a conventional (001) structure. We show that the calculated strain field in a (111)-oriented quantum dot displays the correct C3v symmetry of the underlying crystal structure, even though we use a continuum-based approach and the quantum dot geometry is higher in symmetry than C3v, e.g., C∞v. This behavior originates from an in-plane angle dependence of certain elastic tensor components in the (111)-zinc-blende system. In addition, we compare the elastic and the first-order piezoelectric tensor of the (111)-zinc-blende systems with the corresponding quantities in a wurtzite structure and point out similarities and differences. This comparison provides, for example, insight into the sign of the shear piezoelectric coefficient e15 in the wurtzite system, which is still under debate in the literature. Our analysis indicates e15<0, in accordance with recent experimental and theoretical results.

  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.

  9. Thickness and temperature dependence of the magnetodynamic damping of pulsed laser deposited La0.7Sr0.3MnO3 on (111)-oriented SrTiO3

    NASA Astrophysics Data System (ADS)

    Flovik, Vegard; Macià, Ferran; Lendínez, Sergi; Hernàndez, Joan Manel; Hallsteinsen, Ingrid; Tybell, Thomas; Wahlström, Erik

    2016-12-01

    We have investigated the magnetodynamic properties of La0.7Sr0.3MnO3 (LSMO) films of thickness 10, 15 and 30 nm grown on (111)-oriented SrTiO3 (STO) substrates by pulsed laser deposition. Ferromagnetic resonance (FMR) experiments were performed in the temperature range 100-300 K, and the magnetodynamic damping parameter α was extracted as a function of both film thickness and temperature. We found that the damping is lowest for the intermediate film thickness of 15 nm with α ≈ 2 ·10-3 , where α is relatively constant as a function of temperature well below the Curie temperature of the respective films.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Theoretical analysis of influence of random alloy fluctuations on the optoelectronic properties of site-controlled (111)-oriented InGaAs/GaAs quantum dots

    NASA Astrophysics Data System (ADS)

    Benchamekh, R.; Schulz, S.; O'Reilly, E. P.

    2016-09-01

    We use an s p3d5s* tight-binding model to investigate the electronic and optical properties of realistic site-controlled (111)-oriented InGaAs/GaAs quantum dots. Special attention is paid to the impact of random alloy fluctuations on several factors that determine the fine-structure splitting in these systems. Using a pure InAs/GaAs quantum dot as a reference system, we show that the combination of spin-orbit coupling and biaxial strain effects can lead to sizable spin-splitting effects in these systems. Then, a realistic alloyed InGaAs/GaAs quantum dot with 25% InAs content is studied. Our analysis reveals that the impact of random alloy fluctuations on the electronic and optical properties of (111)-oriented InGaAs/GaAs quantum dots reduces strongly as the lateral size of the dot increases and approaches realistic sizes. For instance the optical matrix element shows an almost vanishing anisotropy in the (111)-growth plane. Furthermore, conduction and valence band mixing effects in the system under consideration are strongly reduced compared to standard (100)-oriented InGaAs/GaAs systems. All these factors indicate a reduced fine-structure splitting in site-controlled (111)-oriented InGaAs/GaAs quantum dots. Thus, we conclude that quantum dots with realistic (50-80 nm) base length represent promising candidates for polarization-entangled-photon generation, consistent with recent experimental data.

  2. [111]-oriented PIN-PMN-PT crystals with ultrahigh dielectric permittivity and high frequency constant for high-frequency transducer applications

    NASA Astrophysics Data System (ADS)

    Li, Fei; Zhang, Shujun; Luo, Jun; Geng, Xuecang; Xu, Zhuo; Shrout, Thomas R.

    2016-08-01

    The electromechanical properties of [111]-oriented tetragonal Pb(In1/2Nb1/2O3)-Pb(Mg1/3Nb2/3O3)-PbTiO3 (PIN-PMN-PT) crystals were investigated for potential high frequency ultrasonic transducers. The domain-engineered tetragonal crystals exhibit an ultrahigh free dielectric permittivity ɛ33T > 10 000 with a moderate electromechanical coupling factor k33 ˜ 0.79, leading to a high clamped dielectric permittivity ɛ33S of 2800, significantly higher than those of the rhombohedral relaxor-PT crystals and high-K (dielectric permittivity) piezoelectric ceramics. Of particular significance is that the [111]-oriented tetragonal crystals were found to possess high elastic stiffness, with frequency constant N33 of ˜2400 Hz m, allowing relatively easy fabrication of high-frequency transducers. In addition, no scaling effect of piezoelectric and dielectric properties was observed down to thickness of 0.1 mm, corresponding to an operational frequency of ˜24 MHz. These advantages of [111]-oriented tetragonal PIN-PMN-PT crystals will benefit high-frequency ultrasonic array transducers, allowing for high sensitivity, broad bandwidth, and reduced noise/crosstalk.

  3. 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.

  4. Microstructure and conduction behavior of BiFeO3 thin film deposited on Ge-doped ZnO

    NASA Astrophysics Data System (ADS)

    Raghavan, Chinnambedu Murugesan; Choi, Ji Ya; Kim, Sang Su

    2017-02-01

    BiFeO3 (BFO) thin films were deposited on a Ge-doped ZnO (GZO)/Si(100) and a Pt(111)/Ti/SiO2/Si(100) using a pulsed laser deposition technique. An improved crystal growth property was observed for the BFO thin film deposited on the GZO/Si(100). The BFO thin film, which was deposited on the (00 l) textured GZO/Si(100), exhibited preferred ( l00) orientated grains, while randomly orientated grains were observed for the thin film deposited on the Pt(111)/Ti/SiO2/Si(100). When compared with the Pt/BFO/Pt capacitor, the GZO/BFO/GZO capacitor exhibited improved conduction behaviors, such as a low leakage current density and high stability against electrical breakdown. From the J-E curves, conduction of the GZO/BFO/GZO and the Pt/BFO/Pt capacitors was found to be dominated by Ohmic and space charge limited conductions at low and high electric field, respectively.

  5. Detection mechanism of perovskite BFO (1 1 1) membrane for FOX-7 and TATB gases: molecular-scale insight into sensing ultratrace explosives

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

    Perovskite bismuth ferrite-BFO (1 1 1) membranes, as potential-sensitive electrochemical sensors, are investigated for the detection of high-energy-density materials by molecular dynamics (MD) and density functional theory (DFT) calculations. For the detection mechanism of the sensitive 1, 1-diamino-2, 2-dinitroethylene (FOX-7) gases, both a cation bridge and electrostatic models can be used to explain the STM signatures as 0.02–0.04 V (single) and 0.03~0.05 V (coverage) over a wide range (0–0.1 V) of bias voltages. For insensitive 1, 3, 5-triamino-2, 4, 6-trinitrobenzene (TATB) gases interacting with the surface of a BFO (1 1 1) membrane, the charge signature can be as high as 0.08 V (coverage: 0.06 V). Analysis indicates a significant difference from the detection mechanism observed for FOX-7 gases; that is, the molecularly intact bidentate bridge configuration with only –\\text{NO}2- bonds binds to both Fe and Bi atoms. These differences are attributed so that the surface O2‑ of BFO will capture a part of the surface electron of the –NO2 group, creating a 2p-hole defect (h+) which annihilates a spinning upward (↑) Fe3+, forming a spinning downward (↓) Fe2+. The –NO2 electron decreases 0.35 e (single FOX-7; coverage FOX-7: 0.24 e) and 0.56 e (single TATB; coverage TATB: 0.06 e). Such a system could open up new ideas in the design and application of BFO-based sensors.

  6. Two-dimensional electron gas at surfaces of (001), (110), and (111) oriented SrTiO3 induced by Ar+-irradiation

    NASA Astrophysics Data System (ADS)

    Miao, Ludi; Du, Renzhong; Yin, Yuewei; Li, Qi

    2015-03-01

    Two-dimensional electron gases (2DEGs) at transition metal oxide surfaces and interfaces have attracted much attention due to their fascinating exotic properties such as superconductivity, large magneto-resistance (MR), and ferromagnetism. We have created 2DEGs at the surfaces of (001), (110), and (111) oriented SrTiO3 (STO) by Ar+-irradiation and measured their transport properties. The 2DEGs exhibit a fully metallic behavior with the 2D charge carrier density around 2 ×1014 cm-2 and the mobility as large as 5500 cm2V-1s-1 at low temperatures, which is tunable by electric fields applied through STO back gates. We have measured MR anisotropy of the 2DEGs at surfaces of STO with all orientations. We observed combinations of two types of components in their anisotropic MR at low temperatures. While the first type is an STO-orientation-independent two-fold component results from the Lorentz force effect, the second type shows stark differences between these 2DEGs as a consequence of distinct Fermi surface symmetries with different STO orientations. Indeed, it is four-fold for STO (001), two-fold for STO (110) and six-fold for STO (111), respectively.

  7. Temperature effects on interface polarons in a strained (111)-oriented zinc-blende GaN/AlGaN heterojunction under pressure

    NASA Astrophysics Data System (ADS)

    Min, Zhang; Shiliang, Ban

    2009-03-01

    The properties of interface polarons in a strained (111)-oriented zinc-blende GaN/AlxGa1-xN heterojunction at finite temperature under hydrostatic pressure are investigated by adopting a modified LLP variational method and a simplified coherent potential approximation. Considering the effect of hydrostatic pressure on the bulk longitudinal optical phonon mode, two branches interface-optical phonon modes and strain, respectively, we calculated the polaronic self-trapping energy and effective mass as functions of temperature, pressure and areal electron density. The numerical result shows that both of them near linearly increase with pressure but the self-trapping energies are nonlinear monotone increasing with increasing of the areal electron density. They are near constants below a range of temperature whereas decrease dramatically with increasing temperature beyond the range. The contributions from the bulk longitudinal optical phonon mode and one branch of interface optical phonon mode with higher frequency are important whereas the contribution from another branch of interface optical phonon mode with lower frequency is extremely small so that it can be neglected in the further discussion.

  8. Surface functionalization of BiFeO3: A pathway for the enhancement of dielectric and electrical properties of poly(methyl methacrylate)-BiFeO3 composite films

    NASA Astrophysics Data System (ADS)

    Mishra, Mukesh Kumar; Moharana, Srikanta; Behera, Banarji; Mahaling, Ram Naresh

    2017-03-01

    A novel two-phase composite film is prepared by the solvent casting method employing poly(methyl methacrylate) (PMMA) as polymer matrix and bismuth ferrite (BFO) as ceramic filler. The surfaces of BFO are functionalized by proper hydroxylating agents to activate their chemical nature. The structural analysis of the composite films confirms that the composites made up of functionalized BFO (BFO-OH) have a distorted rhombohedral structure. The morphological analysis shows that BFO-OH particles are equally distributed over the polymer matrix. The -OH functionality of BFO-OH is confirmed by FTIR. The dielectric and electrical studies at a frequency range from 100 Hz to 1 MHz reveal that PMMA-(BFO-OH) composites have enhanced dielectric constant as well as electrical conductivities, much higher than that of unmodified composites. According to the ferroelectric measurement result, the hydroxylated composite film shows a superior ferroelectric behavior than that of the unmodified one, with a remanent polarization (2 P r) of 2.764 μC/cm2.

  9. Heteroepitaxial growth and characterization of BiFeO3 thin films on GaAs

    NASA Astrophysics Data System (ADS)

    Shafiqur Rahman, Md; Ghose, Susmita; Gatabi, Javad R.; Rojas-Ramirez, Juan S.; Pandey, R. K.; Droopad, Ravi

    2016-10-01

    The paper deals with the integration of well-known bismuth ferrite (BiFeO3) multiferroic oxide with GaAs semiconductor. First 5 nm ultrathin SrTiO3 films were grown on GaAs (001) substrates as an intermediate buffer layer by molecular beam epitaxy. Then, room temperature multiferroic BiFeO3 (BFO) thin films were deposited by pulsed laser deposition. X-ray diffraction measurement showed high quality epitaxial BFO films with pure (00l) orientation. The dielectric loss has been effectively suppressed and the saturated polarization-voltage (P-V) hysteresis loops were obtained. The ferroelectric domains switching was affirmed by piezo-response force microscopic studies. A large remnant polarization P r (˜80 μC cm-2) combined with the enhanced magnetization (72 emu cm-3) at 300 K was achieved for the optimal growth conditions. The optical properties were measured using the ellipsometry technique for the BFO thin films. The thickness and optical constants of the BFO films were obtained by taking into consideration the dielectric parameters as described by the Tauc-Lorentz model. Finally, direct bandgap was estimated at 2.70 eV which is highly comparable to BFO films grown on different substrates.

  10. Strain evolution of epitaxial tetragonal-like BiFeO3 thin films on LaAlO3(001) substrates prepared by sputtering and their bulk photovoltaic effect

    NASA Astrophysics Data System (ADS)

    Nakashima, Seiji; Uchida, Tomohisa; Doi, Kentaro; Saitoh, Koh; Fujisawa, Hironori; Sakata, Osami; Katsuya, Yoshio; Tanaka, Nobuo; Shimizu, Masaru

    2016-10-01

    The structural evolution of high-quality 3.3-73.2-nm-thick tetragonal-like BiFeO3 (T-BFO) thin films grown on LaAlO3(001) substrates and the bulk photovoltaic effect of the films were investigated. The T-BFO films were grown by rf magnetron sputtering, showing the Peudellösung fringes around the T-BFO (001) diffraction peak in X-ray diffraction θ-2θ patterns. These indicate the structural coherence between the surface and the interface in the surface normal direction of the films. High-resolution synchrotron X-ray diffraction analysis and transmission electron microscopy reveal that the lattice relaxation behavior from the MA monoclinic to MC monoclinic structure occurs as the film thickness increases. The domain structure was partly controlled by using a vicinal LAO (001) substrate along [100]. Regarding the current-voltage characteristics of the Pt/T-BFO/Pt coplanar capacitor under violet laser illumination, T-BFO films show an anomalous photovoltaic effect with an open-circuit voltage of 6.1 V and a short-circuit current of -290 pA along the [100]T-BFO direction.

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

    PubMed

    Jian, Sheng-Rui; Chang, Huang-Wei; Tseng, Yu-Chin; Chen, Ping-Han; Juang, Jenh-Yih

    2013-06-25

    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.

  12. Raman scattering spectra, magnetic and ferroelectric properties of BiFeO3-CoFe2O4 nanocomposite thin films structure

    NASA Astrophysics Data System (ADS)

    Tyagi, Mintu; Kumari, Mukesh; Chatterjee, Ratnamala; Sharma, Puneet

    2014-09-01

    Multiferroic (1-x)BiFeO3(BFO)-xCoFe2O4(CFO) (x=0 and 0.1) nanocomposite thin films were deposited on ITO coated glass using sol-gel spin coating technique. X-ray diffraction and transmission electron microscopy examinations confirm the coexistence of both perovskite BFO and spinel CFO phases. The effect of addition of CFO in BFO matrix has been studied on Raman spectra, magnetic and ferroelectric properties. BFO/CFO nanocomposite showed good magnetic behavior (Ms 40.3 emu/cm3, Mr 12.9 emu/cm3, Hc 90 Oe) with no change in ferroelectric properties. The strain analysis carried out by Raman spectroscopy reveals that both BFO and CFO bands are found to be strained in BFO/CFO composite nanostructure. The strain of the bands is discussed on the basis of lattice mismatch (interfacial stress) between CFO (a=0.839 nm) and BFO (a=0.396 nm) phases.

  13. Study on polarization characteristics of BiFeO3 thin films prepared by sol-gel spin-coating technology

    NASA Astrophysics Data System (ADS)

    Jia, Ze; Wu, Xiao; Zhang, Mingming; Xu, Jianlong; Zhang, Naiwen; Liou, Juin J.

    2015-07-01

    The ferroelectric polarization properties of bismuth ferrite (BFO) thin films deposited on Pt(111)/TiO2/SiO2/Si(100) substrates by sol-gel spin-coating technology affected by the processes and dopants have been studied and analyzed tentatively. The results indicate BFO thin film should be introduced to a rapid thermal annealing (RTA) process at N2 atmosphere. The enhanced ferroelectric polarization properties were observed in Mn and La doped BFO thin films, because ion substitution may improve the inherent volatility of Bi atoms, valence fluctuation of Fe ions and magnetic spin structures, reducing the formation of oxygen vacancies. The increased remnant polarization observed in the BFO thin film with a lead zirconate titanate (PZT) seeding layer has also been analyzed as the probable results of small changes of lattice parameters caused by constraint stress, reduced defects and decreased leakage current density, which are contributed by the PZT seeding layer possibly. Moreover, the remnant polarization approximately 79 μC/cm2 is observed in (Bi0.95La0.05)FeO3 (BLFO) thin film with a PZT seeding layer, which is twice and treble the values of BFO thin films with and without a PZT seeding layer, indicating PZT seeding layer is much more effective for BLFO thin film which has a substitution at A site.

  14. 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.

  15. 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.

  16. Enhanced ferroelectric photoelectrochemical properties of polycrystalline BiFeO{sub 3} film by decorating with Ag nanoparticles

    SciTech Connect

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

    2016-01-11

    Polycrystalline BiFeO{sub 3} (BFO) films are fabricated on Pt/Ti/SiO{sub 2}/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.

  17. 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

  18. 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.

  19. Density relative change and interface zone mutual diffusion of BiFeO3 films prepared on Si (1 0 0), SiO2 and SiO2/Si (1 0 0)

    NASA Astrophysics Data System (ADS)

    Xiao, RenZheng; Wang, ZeSong; Yuan, XianBao; Zhou, JianJun; Mao, ZhangLiang; Su, HuaShan; Li, Bo; Fu, DeJun

    2016-10-01

    The mutual diffusion taken place in the interface zone between BiFeO3 (BFO) films and substrates (Si (1 0 0), SiO2 and SiO2/Si (1 0 0)) has been revealed by energy dispersive X-ray spectroscopy (EDS) and Rutherford Backscattering Spectrometry (RBS). RBS spectra provide the relative atomic concentrations of Bi, Fe, Si, and O elements changed with the samples' depth as analyzed by RBS spectra fitting SIMNRA software. A certain width of the intermixing layer is probably formed between BFO films and individual substrate which is attributed to mutual diffusion in the interface zone during annealing process. The mechanism of concerted exchange component can explain the interface zone mutual diffusion phenomenon between BFO films and substrates. The width of the interface zone between BFO film and Si (1 0 0), SiO2, and SiO2/Si (1 0 0) substrate is about 1.94 × 1017, 2.01 × 1017 and 3.05 × 1017 atoms/cm2, respectively, which are equivalent to 30.9, 36.7, and 52.9 nm, respectively. It has been declared that the effect on density relative to BFO film is loosen or attenuation is presented in the interface zone, which can be interpreted as a migration or diffusion of various atoms during the annealing. This can also provide an evidence of atomic dynamics and defect engineering on interface diffusion.

  20. Creep-free ac hysteretic dynamics in epitaxial ferroelectric BiFeO3 films

    NASA Astrophysics Data System (ADS)

    Shin, Yeongjae; Jeon, Byung Chul; Yang, Sang Mo; Hwang, Inrok; Cho, Myung Rae; Sando, Daniel; Lee, Seung Ran; Yoon, Jong-Gul; Noh, Tae Won

    2015-03-01

    Dynamics of domain wall (DW) in ferroelectric (FE) films principally governs their switching properties under applied electric field (E) . At finite temperature (T) , the DW motion and their FE switching characteristics can be understood only by introducing the creep motion. Despite this importance, there have been little studies on creep motion of FE films under ac-driven force. In this work, we investigate ac-driven hysteretic dynamics of FE domains in epitaxial BiFeO3 (BFO) films through polarization-electric field hysteresis loops with varying frequency and other switching characters. All BFO films were grown at the optimized growth condition, by employing different bottom electrodes of La0.67Sr0.33MnO3 (LSMO) and SrRuO3 (SRO); only BFO/SRO shows nearly creep-free hysteretic dynamics. We argue that inhomogeneous internal E plays a significant role in such distinctive FE dynamics of BFO domains, which are affected by surface morphologies of bottom electrodes. Our results highlight that growth-mode-induced interfacial structure between an FE film and a bottom electrode result in engineering domain dynamics of FE switching characteristics. This work was supported by IBS-R009-D1.

  1. 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.

  2. Modulation of ultrafast laser-induced magnetization precession in BiFeO3-coated La0.67Sr0.33MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Wan, Qian; Jin, KuiJuan; Wang, JieSu; Yao, HongBao; Gu, JunXing; Guo, HaiZhong; Xu, XiuLai; Yang, GuoZhen

    2017-04-01

    The ultrafast laser-excited magnetization dynamics of ferromagnetic (FM) La0.67Sr0.33MnO3 (LSMO) thin films with BiFeO3 (BFO) coating layers grown by laser molecular beam epitaxy are investigated using the optical pump-probe technique. Uniform magnetization precessions are observed in the films under an applied external magnetic field by measuring the time-resolved magneto-optical Kerr effect. The magnetization precession frequencies of the LSMO thin films with the BFO coating layers are lower than those of uncoated LSMO films, which is attributed to the suppression of the anisotropy field induced by the exchange interaction at the interface between the antiferromagnetic order of BFO and the FM order of LSMO.

  3. Structural transformation and multiferroic properties of single-phase Bi0.89Tb0.11Fe1-xMnxO3 thin films

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    Pure BiFeO3 (BFO) and Tb, Mn co-doped BiFeO3 (BTFMO) thin films were deposited on SnO2: F (FTO)/glass substrates using a chemical solution deposition method. Detailed investigations were made on the influence of (Tb, Mn) co-doping on the structure change and the electric properties of the BFO films. With the co-doping of Tb and Mn, the structural transformation from rhombohedral R3c to triclinic P1 is confirmed through XRD, Rietveld refinement and Raman analysis. XPS analysis clarifies that (Tb, Mn) co-doping avails to decrease oxygen vacancy concentration, showing less Fe2+ ions in the co-doped BTFMO thin films than that of the pure BFO thin film. Among the co-doped thin films, the BTFM1O film shows the highly enhanced ferroelectric properties with a giant remnant polarization value (2Pr = 180.3 μC/cm2). The structural transformation, the well-distributed fine grains and the reduction of leakage current favor enhanced ferroelectric property of (Tb, Mn) co-doped BFO films. It is also found that the BTFM1O film shows the enhanced ferromagnetism with the saturated magnetization (Ms = 2.5 emu/cm3) as a result of the collapse of space modulated spin structure by the structure transformation.

  4. Structural transitions and enhanced ferroelectricity in Ca and Mn co-doped BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Huang, Ji-Zhou; Shen, Yang; Li, Ming; Nan, Ce-Wen

    2011-11-01

    Ca and Mn co-doped BiFeO3 (BFO) thin films were fabricated on (111) Pt/Ti/SiO2/Si substrates via a simple solution approach. Enhanced ferroelectric properties were obtained in these Ca and Mn co-doped BFO films, e.g., large remnant polarization value (Pr ˜ 89 μC/cm2) and large remnant polarization to saturated polarization ratio (Pr/Ps ˜ 0.84) for Bi0.90Ca0.10Fe0.90Mn0.10O3 film. X-ray diffraction and Raman spectra of these films showed that B-site Mn doping causes substantial structural transition toward orthorhombic phase and A-site Ca doping facilitates an evolution to tetragonal phase with higher crystal symmetry. The structural transitions are in favor of enhanced ferroelectric properties in the BFO films. The approach of A and B site co-doping is proved to be effective in enhancing ferroelectric performance in multiferroic BFO films.

  5. 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.

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

    PubMed

    Lee, Seung Min; Cho, Yong Soo

    2016-04-07

    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.

  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. 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.

  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. Magnetic and structural properties of BiFeO3 thin films grown epitaxially on SrTiO3/Si substrates

    NASA Astrophysics Data System (ADS)

    Laughlin, Ryan P.; Currie, Daniel A.; Contreras-Guererro, Rocio; Dedigama, Aruna; Priyantha, Weerasinghe; Droopad, Ravindranath; Theodoropoulou, Nikoleta; Gao, Peng; Pan, Xiaoqing

    2013-05-01

    The integration of oxides with semiconductors is important for the technological advancement of the next generation electronics. Concomitant ferroelectric and antiferromagnetic (AF) behavior is demonstrated in single crystal BiFeO3 (BFO) films grown on 20 nm SrTiO3 (STO) virtual substrates on Si(100) using molecular beam epitaxy (MBE). STO thin films are grown in an oxide MBE chamber by co-deposition of Sr, Ti, and molecular O2. Careful control of the O2 during nucleation produced commensurate growth of STO on Si. The sequence of the steps allows for the suppression of an amorphous SiO2 layer. This STO(20 nm)/Si structure was used as a virtual substrate for MBE deposition of BFO on Si without breaking vacuum. BFO was deposited using Fe and O2 plasma with an overpressure of Bi flux, the growth rate was controlled by the incoming Fe flux. The reflection high energy electron diffraction image shows a 2-D growth front with a 6-fold surface reconstruction under optimized O2 pressure of 5 × 10-8 mbar. Cross-sectional transmission electron microscopy (TEM) confirms the high crystallinity of the films and shows sharp, atomically flat interfaces. The selected area diffraction pattern (SADP) reveals that BFO grows in a distorted rhombohedral crystal structure. X-ray diffraction does not show formation of second phases and is consistent with the TEM and SADP results. The BFO films show AF behavior with a Neel temperature that exceeds 350 K, as expected (TN = 673 K) and with a residual ferromagnetic behavior that decreases with film thickness and is consistent with the G-type AF due to the canted spins. The saturation magnetization per unit volume for a 40 nm thick film was 180 emu/cm3 at an in-plane magnetic field of 8 kOe. The ferroelectric behavior of the films was verified using piezoresponse force microscopy.

  12. 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.

  13. 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.

  14. Structure and conductivity of epitaxial thin films of barium ferrite and its hydrated form BaFeO2.5‑x+δ (OH)2x

    NASA Astrophysics Data System (ADS)

    Anitha Sukkurji, Parvathy; Molinari, Alan; Benes, Alexander; Loho, Christoph; Sai Kiran Chakravadhanula, Venkata; Garlapati, Suresh Kumar; Kruk, Robert; Clemens, Oliver

    2017-03-01

    Barium ferrite and its hydrated form (BaFeO2.5‑x+δ (OH)2x , BFO) is an interesting cathode material for protonic ceramic fuel cells (PCFC) due to its potential to be both, conducting for electrons and protons. We report on the fabrication of almost epitaxially grown thin films (22 nm) of barium ferrite BaFeO~2.5 (BFO) on Nb-doped SrTiO3 substrates via pulsed laser deposition (PLD), followed by treatment under inert, and subsequently wet inert atmospheres to induce water (respectively proton) incorporation. Microstructure, chemical composition and conducting properties are investigated for the BFO films and their hydrated forms, highlighting the influence of hydration on the conductivity characteristics between ~200–290 K. We find that water incorporation gives a strong enhancement of the conductivity to ~10‑9 S cm‑1 compared to argon annealed films, inducing electronic and protonic charge carriers at the same time. In comparison to bulk powders, proton conductivity is found to be strongly suppressed in such thin hydrated BFO films, pointing towards the influence of strain on the conductivity, which is evaluated based on a detailed investigation by high-resolution transmission electron microscopy.

  15. 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.

  16. Films.

    ERIC Educational Resources Information Center

    Philadelphia Board of Education, PA. Div. of Instructional Materials.

    The Affective Curriculum Research Project produced five films and two records during a series of experimental summer programs. The films and records form part of a curriculum designed to teach to the concerns of students. The films were an effort to describe the Philadelphia Cooperative Schools Program, to explain its importance, and to…

  17. Films

    NASA Astrophysics Data System (ADS)

    Li, Ming; Zhang, Yang; Shao, Yayun; Zeng, Min; Zhang, Zhang; Gao, Xingsen; Lu, Xubing; Liu, J.-M.; Ishiwara, Hiroshi

    2014-09-01

    In this paper, we investigated the microstructure and electrical properties of Bi2SiO5 (BSO) doped SrBi2Ta2O9 (SBT) films deposited by chemical solution deposition. X-ray diffraction observation indicated that the crystalline structures of all the BSO-doped SBT films are nearly the same as those of a pure SBT film. Through BSO doping, the 2Pr and 2Ec values of SBT films were changed from 15.3 μC/cm2 and 138 kV/cm of pure SBT to 1.45 μC/cm2 and 74 kV/cm of 10 wt.% BSO-doped SBT. The dielectric constant at 1 MHz for SBT varied from 199 of pure SBT to 96 of 10 wt.% BSO-doped SBT. The doped SBT films exhibited higher leakage current than that of non-doped SBT films. Nevertheless, all the doped SBT films still had small dielectric loss and low leakage current. Our present work will provide useful insights into the BSO doping effects to the SBT films, and it will be helpful for the material design in the future nonvolatile ferroelectric memories.

  18. Leakage current characteristics and Sm/Ti doping effect in BiFeO3 thin films on silicon wafers

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Zhou, Zhen; Luo, Jin; Wang, Ke; Li, Jing-Feng

    2017-02-01

    The leakage current of BiFeO3 thin films can be reduced by Sm or Ti doping, and their codoping effect is significant. X-ray photoelectron spectroscopy revealed that the reduction in the leakage current can be ascribed to decreased Fe2+ ions and oxygen vacancies. The leakage mechanisms of pristine and doped BiFeO3 films were studied by analyzing their leakage current characteristics through curve fitting. It was found that Ti could stabilize the trapped carriers, while Sm might decrease the trap energy and contrarily benefit the excitation of the trapped carriers, which explains the greater effect of Ti in reducing the leakage current than that of Sm. The piezoelectric properties of Sm/Ti-codoped BiFe0.9Ti0.1O3 (BFO) films were comparable to those of pristine BFO owing to the enhanced electric breakdown despite their reduced remanent polarization.

  19. Characterization of CdTe Films Deposited at Various Bath Temperatures and Concentrations Using Electrophoretic Deposition

    PubMed Central

    Daud, Mohd Norizam Md; Zakaria, Azmi; Jafari, Atefeh; Ghazali, Mohd Sabri Mohd; Abdullah, Wan Rafizah Wan; Zainal, Zulkarnain

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established. PMID:22754325

  20. Characterization of CdTe films deposited at various bath temperatures and concentrations using electrophoretic deposition.

    PubMed

    Daud, Mohd Norizam Md; Zakaria, Azmi; Jafari, Atefeh; Ghazali, Mohd Sabri Mohd; Abdullah, Wan Rafizah Wan; Zainal, Zulkarnain

    2012-01-01

    CdTe film was deposited using the electrophoretic deposition technique onto an ITO glass at various bath temperatures. Four batch film compositions were used by mixing 1 to 4 wt% concentration of CdTe powder with 10 mL of a solution of methanol and toluene. X-ray Diffraction analysis showed that the films exhibited polycrystalline nature of zinc-blende structure with the (111) orientation as the most prominent peak. From the Atomic Force Microscopy, the thickness and surface roughness of the CdTe film increased with the increase of CdTe concentration. The optical energy band gap of film decreased with the increase of CdTe concentration, and with the increase of isothermal bath temperature. The film thickness increased with respect to the increase of CdTe concentration and bath temperature, and following, the numerical expression for the film thickness with respect to these two variables has been established.

  1. Mechanisms for Orientation in Low Energy Ion Beam Assisted TiAlN Thin Film Growth

    NASA Astrophysics Data System (ADS)

    Aliotta, Paul V.

    The effects of off-normal ionized vapor bombardment on the orientation and structure of off-normal sputter deposited TiAlN thin films has been investigated with the goal of better understanding the mechanistic pathways in ion beam assisted thin film growth for better control of film properties during deposition. The effects of incident angle for ion bombardment has been investigated as a potential variable during deposition and a comprehensive comparison to current theories of thin film orientation development has been made. It is shown that for low levels of ion energies and rates, films develop (220) orientation with a near amorphous zone 1 (Z1) morphology for low ion incident angles. As the rates and energies of ions increases, (111) orientation and fibrous transition zone (ZT) morphology develops. It is also seen that as the angle of ion bombardment increases the threshold level for rates and energies of ions to cause (111) orientation and ZT morphologies is reduced. This change in orientation and morphology has been shown to change in-situ according to the level of ion bombardment making this transition a potential tool for developing microstructures within thin films. Commonly accepted theories of thin film orientation have been investigated with respect to the development of (111) orientation for low energy ion beam assisted deposition including surface energy reduction, thermal influences, strain energy reduction, ion channeling, and ion damage anisotropy though such mechanisms were not successful in describing the development of (111) orientation. Atomic subplantation, generally regarded as a mechanism for bond formation in diamond-like carbon films, has also been investigated as a potential mechanism for orientation development. By treating the interaction of ions with the depositing film as a collision between ion and surface atom, the transition from (220) to (111) orientation is found to occur when the average energy transferred per atom normal to the

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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 Al2O3 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.

  4. Tracking the amorphous to epitaxial transition in RF-sputtered cubic BFO-STO heterojunctions by means of X-ray photoelectron diffraction

    NASA Astrophysics Data System (ADS)

    Giampietri, Alessio; Drera, Giovanni; Píš, Igor; Magnano, Elena; Sangaletti, Luigi

    2016-09-01

    The epitaxial growth of cubic BiFeO3 ultrathin films on SrTiO3 (001) substrates by off-axis RF sputtering is demonstrated, suitable to X-ray spectroscopies interface investigation. X-ray photoelectron diffraction is used as a tool to probe the long-range crystal order and to track the transition from amorphous to epitaxial growth as a function of deposition parameters. Further spectroscopic measurements, in particular, X-ray linear dichroism on the Fe L 3 , 2 edge, confirm the heteroepitaxial growth of BiFeO3 and clearly indicate a 3+ valence state for the iron cation. Finally, XPS is used to reconstruct the band alignment diagram, which results in a staggered configuration with a remarkable energy shift of the SrTiO3 band edges which can ultimately favor the n-type doping of SrTiO3.

  5. 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.

  6. Thickness Dependence of Photovoltaic Effect in BiFeO3 Thin Films Based on Asymmetric Structures

    NASA Astrophysics Data System (ADS)

    Gao, Rongli; Fu, Chunling; Cai, Wei; Chen, Gang; Deng, Xiaoling; Cao, Xianlong

    2017-04-01

    BiFeO3 (BFO) thin films with different layers were deposited on Pt/Ti/SiO2/Si substrates via the sol-gel method, and the effect of nonuniform electric field formed by asymmetry electrodes on the photovoltaic properties has been investigated through experimental approaches. The Au/BFO/Pt heterostructures show 1.3 V open-circuit voltages and ˜0.242% photovoltaic power conversion efficiency when illuminated under sunlight (AM 1.5), this high efficiency is at least one order of magnitude larger than many other values thus far reported for BFO-based devices prepared by the spin coated method. The film layer dependence of the photovoltaic effect suggests that the large open-circuit voltage and high efficiency are contributed by both the ferroelectric polarization and the asymmetric structures formed by top and bottom electrodes. Theoretical analysis indicates that the efficiency may be further significantly improved by increasing the number of film layers and the nonuniform depolarization field, implying potential applications.

  7. Influence of the polarization anisotropy on the electrocaloric effect in epitaxial PMN-PT thin films

    NASA Astrophysics Data System (ADS)

    Mietschke, M.; Chekhonin, P.; Molin, C.; Gebhardt, S.; Fähler, S.; Nielsch, K.; Schultz, L.; Hühne, R.

    2016-09-01

    Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) compounds, which are typically used for high performance actuator applications due to their outstanding piezoelectric properties, show, in addition, a pronounced electrocaloric (EC) effect. The study of epitaxial films is a useful tool to analyze the correlation between the microstructure and EC properties in order to optimize the performance of these materials. Therefore, the 0.9PMN-0.1PT films were grown by a pulsed laser deposition on (001) as well as (111) oriented SrTiO3 single crystalline substrates using a La0.7Sr0.3CoO3 buffer as the bottom electrode and additional Au top electrodes. The structural properties determined by a high resolution X-ray and electron microscopy techniques indicated an undisturbed epitaxial growth. The anisotropy of the ferroelectric domain structure was investigated by a vertical and lateral piezoresponse force microscopy showing clear differences between the two orientations. A significant reduction of the thermal hysteresis was observed in the T-dependent polarization measurements for (111) oriented PMN-PT films, whereas the indirectly determined EC properties yield a maximum ΔT of around 15 K at 40 °C for a field of about 400 kV/cm for both film orientations.

  8. Charge defects and highly enhanced multiferroic properties in Mn and Cu co-doped BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    Pure BiFeO3 (BFO) and Mn, Cu co-doped BiFeO3 (BFMCO) thin films were deposited on fluorine doped tin oxide (FTO) substrates by a chemical solution deposition method. Detailed investigations were made on the effects of Mn and Cu co-doping on the crystal structure, the defect chemistry, multiferroic properties of the BFO thin films. With the co-doping of Mn and Cu, a structural transition from the rhombohedral (R3c:H) to the biphasic structure (R3c:H + P1) is confirmed by XRD, Rietveld refinement and Raman analysis. X-ray photoelectron spectroscopy (XPS) analysis shows that the coexistence of Fe2+/Fe3+ and Mn2+/Mn3+ ions in the co-doping films are demonstrated. Meanwhile, the way of the co-doping at B-sits is conducive to suppress Fe valence state of volatility and to decrease oxygen vacancies and leakage current. It's worth noting that the co-doping can induce the superior ferroelectric properties (a huge remanent polarization, 2Pr ∼ 220 μC/cm2 and a relatively low coercive field, 2Ec ∼ 614 kV/cm). The introduction of Mn2+ and Cu2+ ions optimizes the magnetic properties of BFO thin films by the biphasic structure and the destruction of spin cycloid.

  9. Avoiding polar catastrophe in the growth of polarly orientated nickel perovskite thin films by reactive oxide molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Yang, H. F.; Liu, Z. T.; Fan, C. C.; Yao, Q.; Xiang, P.; Zhang, K. L.; Li, M. Y.; Liu, J. S.; Shen, D. W.

    2016-08-01

    By means of the state-of-the-art reactive oxide molecular beam epitaxy, we synthesized (001)- and (111)-orientated polar LaNiO3 thin films. In order to avoid the interfacial reconstructions induced by polar catastrophe, screening metallic Nb-doped SrTiO3 and iso-polarity LaAlO3 substrates were chosen to achieve high-quality (001)-orientated films in a layer-by-layer growth mode. For largely polar (111)-orientated films, we showed that iso-polarity LaAlO3 (111) substrate was more suitable than Nb-doped SrTiO3. In situ reflection high-energy electron diffraction, ex situ high-resolution X-ray diffraction, and atomic force microscopy were used to characterize these films. Our results show that special attentions need to be paid to grow high-quality oxide films with polar orientations, which can prompt the explorations of all-oxide electronics and artificial interfacial engineering to pursue intriguing emergent physics like proposed interfacial superconductivity and topological phases in LaNiO3 based superlattices.

  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. Superconducting tunneling studies on thin film gold nanowires coupled to a BCS superconductor

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    The nanowire patterned out of (111)-oriented gold thin film is an excellent candidate for hosting Majorana bound states (MBS) when it is coupled to an s-wave superconductor. The robust MBS is guaranteed by the large Rashba spin-orbit coupling (SOC) of gold surface state, as well as by large spatial separations between the two MBS in fabricated micrometer size long nanowires. In addition, being able to produce complex nanowire circuit, our approach is better streamlined for achieving the braiding circuit of Majorana fermions. We present our experimental approach of growing high quality hetero-layers consisting of epitaxial (111)-oriented gold thin film on vanadium using molecular beam epitaxy (MBE). Unique lithography processes are developed to pattern the top gold thin film into nanowires with a width around 100nm without damaging the hetero-layers such as its topography or superconducting behavior. Superconductive tunneling studies are performed over the gold nanowire using lithographically fabricated planar tunnel junctions. These tunneling characteristics will be discussed. We acknowledge support from John Templeton Foundation, NSF DMR-1207469 and ONR N00014-13-1-0301.

  12. Magneto-optical bismuth-substituted bubble garnet films for magnetic field sensors

    NASA Astrophysics Data System (ADS)

    Randoshkin, Vladimir V.

    1990-10-01

    In the present paper it is shown that the magneto-optical (MO) bismuth-substituted bubble garnet films are attractive for Paraday magnetic field (current) sensors with the rise time about 10 ns. This problem can be solved if the sensors are based on the films with domain wall velocity up to 1000 rn/s and. domain wall mobility about 10 rn/Cs Oe) or more. Using high-speed photography method the two kinds of materials with the high dynamical parameters were studied: 1) (111)-oriented (Tm,Gd,BiL(Pe,Ga)O10 films with high gy- romagnetic ratio ; 2) (21O)-oriente (Y, Lu,r,i) 3(Pe, Ga) 512 films with orthorhombic anisotropy.

  13. Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films

    DOE PAGES

    Gallagher, J. C.; Esser, B. D.; Morrow, R.; ...

    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. Effect of (Bi, La)(Fe, Zn)O{sub 3} thickness on the microstructure and multiferroic properties of BiFeO{sub 3} thin films

    SciTech Connect

    Wu Jiagang; Xiao Dingquan; Zhu Jianguo

    2012-11-01

    The effect of Bi{sub 0.90}La{sub 0.10}Fe{sub 0.90}Zn{sub 0.10}O{sub 3} (BLFZO) thicknesses on the microstructure and multiferroic properties of BiFeO{sub 3} (BFO) thin films was investigated, and all bilayered thin films were grown on Pt-coated silicon substrates without any buffer layers by a radio frequency sputtering. A (110) orientation is dominant in all the bilayers, and two grain growth modes are identified in these bilayers by using an atomic force microscope, where different grain growth modes significantly affect their leakage behavior. The dielectric constant ({epsilon}{sub r}) of bilayers gradually increases, and magnetic properties were deteriorated with the addition of BLFZO with a higher {epsilon}{sub r} and a weaker magnetic behavior. An enhanced ferroelectric behavior of 2P{sub r} {approx} 116.2 {mu}C/cm{sup 2} and 2E{sub c} {approx} 524 kV/cm could be observed in the BFO/BLFZO bilayered thin film with 80 nm BLFZO layer owing to a higher orientation degree of (110) and an interface coupling together with a lower leakage current density. As a result, electrical properties of BFO could be tailored by modifying the thicknesses of BLFZO.

  16. Electron mobility enhancement in epitaxial multilayer Si-Si/1-x/Ge/x/ alloy films on /100/Si

    NASA Technical Reports Server (NTRS)

    Manasevit, H. M.; Gergis, I. S.; Jones, A. B.

    1982-01-01

    Enhanced Hall-effect mobilities have been measured in epitaxial (100)-oriented multilayer n-type Si/Si(1-x)Ge(x) films grown on single-crystal Si substrates by chemical vapor deposition. Mobilities from 20 to 40% higher than that of epitaxial Si layers and about 100% higher than that of epitaxial SiGe layers on Si were measured for the doping range 8 x 10 to the 15th to 10 to the 17th/cu cm. No mobility enhancement was observed in multilayer p-type (100) films and n-type (111)-oriented films. Experimental studies included the effects upon film properties of layer composition, total film thickness, doping concentrations, layer thickness, and growth temperature.

  17. 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

  18. Epitaxial BiFeO3 nanostructures fabricated by differential etching of BiFeO3 films

    NASA Astrophysics Data System (ADS)

    Johann, Florian; Morelli, Alessio; Vrejoiu, Ionela

    2011-08-01

    We report on differential etching behavior of the different orientations of the polarization in BiFeO3 (BFO), similar to other ferroelectrics, such as LiNbO3. We show how this effect can be used to fabricate epitaxial BiFeO3 nanostructures. By means of piezoresponse force microscopy (PFM) domains of arbitrary shape and size can be poled in an epitaxial BiFeO3 film, which are then reproduced in the film morphology by differential etching. Structures with a lateral size smaller than 200 nm were fabricated and very good retention properties as well as a highly increased piezoelectric response were detected by PFM.

  19. Low-damping sub-10-nm thin films of lutetium iron garnet grown by molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Jermain, C. L.; Paik, H.; Aradhya, S. V.; Buhrman, R. A.; Schlom, D. G.; Ralph, D. C.

    2016-11-01

    We analyze the structural and magnetic characteristics of (111)-oriented lutetium iron garnet (Lu3Fe5O12) films grown by molecular-beam epitaxy, for films as thin as 2.8 nm. Thickness-dependent measurements of the in- and out-of-plane ferromagnetic resonance allow us to quantify the effects of two-magnon scattering, along with the surface anisotropy and the saturation magnetization. We achieve effective damping coefficients of 11.1 (9 )×10-4 for 5.3 nm films and 32 (3 )×10-4 for 2.8 nm films, among the lowest values reported to date for any insulating ferrimagnetic sample of comparable thickness.

  20. Effect of crystal orientation on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO{sub 3} thin films

    SciTech Connect

    Wu, Huaping E-mail: hpwu@zjut.edu.cn; Ma, Xuefu; Zhang, Zheng; Zeng, Jun; Chai, Guozhong; Wang, Jie

    2016-01-15

    The influence of crystal orientations on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO{sub 3} thin films has been investigated using an expanded nonlinear thermodynamic theory. The calculations reveal that crystal orientation has significant influence on the phase stability and phase transitions in the misfit strain-temperature phase diagrams. In particular, the (110) orientation leads to a lower symmetry and more complicated phase transition than the (111) orientation in BaTiO{sub 3} films. The increase of compressive strain will dramatically enhance the Curie temperature T{sub C} of (110)-oriented BaTiO{sub 3} films, which matches well with previous experimental data. The polarization components experience a great change across the boundaries of different phases at room temperature in both (110)- and (111)-oriented films, which leads to the huge dielectric and piezoelectric responses. A good agreement is found between the present thermodynamics calculation and previous first-principles calculations. Our work provides an insight into how to use crystal orientation, epitaxial strain and temperature to tune the structure and properties of ferroelectrics.

  1. Ferromagnetism and Ru-Ru distance in SrRuO3 thin film grown on SrTiO3 (111) substrate

    PubMed Central

    2014-01-01

    Epitaxial SrRuO3 thin films were grown on both (100) and (111) SrTiO3 substrates with atomically flat surfaces that are required to grow high-quality films of materials under debate. The following notable differences were observed in the (111)-oriented SrRuO3 films: (1) slightly different growth mode, (2) approximately 10 K higher ferromagnetic transition temperature, and (3) better conducting behavior with higher relative resistivity ratio, than (100)c-oriented SrRuO3 films. Together with the reported results on SrRuO3 thin films grown on (110) SrTiO3 substrate, the different physical properties were discussed newly in terms of the Ru-Ru nearest neighbor distance instead of the famous tolerance factor. PACS 75.70.Ak; 75.60.Ej; 81.15.Fg PMID:24393495

  2. Orientation-dependent physical properties of layered perovskite La1.3Sr1.7Mn2O7 epitaxial thin films

    NASA Astrophysics Data System (ADS)

    Niu, Li-Wei; Guo, Bing; Chen, Chang-Le; Luo, Bing-Cheng; Dong, Xiang-Lei; Jin, Ke-Xin

    2017-04-01

    In this paper, the resistivity and magnetization of orientation-engineered layered perovskite La1.3Sr1.7Mn2O7 epitaxial thin films have been investigated. Epitaxial thin films were deposited on single-crystalline LaAlO3 (LAO) (001), (110) and (111) substrates by pulse laser deposition (PLD) technique. It is found that only the (100)-oriented thin film performs insulator behavior, whereas the (110) and (111)-oriented thin films exhibit obvious metal-insulator transition at 70 K and between 85 and 120 K, respectively. Moreover, the same spin freezing temperature and different spin-glass-like transition temperatures have been observed in various oriented films. The observed experimental results were discussed according to the electron-transport mechanism and spin dynamics.

  3. Reactions of saturated hydrocarbons with hydrogen and deuterium on epitaxially oriented (111) Pd and Pd-Au alloy films

    SciTech Connect

    Karpinski, Z.

    1982-09-01

    The reactions of neopentane, n-butane, propane, and n-pentane in the presence of an excess of hydrogen have been studied on evaporated Pd/Au-on-mica films. The characterization of films showed that they were predominantly (111) oriented. The selectivity in hydrogenolysis of all hydrocarbons decreased markedly with an increase in the content in Au. The catalytic activity for isomerization of neopentane and n-butane was higher for ca. 10 at. % Au alloys than for pure Pd. This finding appears to support the mechanism involving 1,2-bond shift isomerization at one metal site proposed by McKervey et al. Additional experiments with CH/sub 4//D/sub 2/ and neopentane/D/sub 2/ exchange over Pd-Au(111) alloys at higher temperatures showed considerable difficulties in forming carbene adspecies which could be responsible for another isomerization route. The isotopic exchange between cyclopentane and deuterium over (111) oriented Pd-Au alloys showed that the rate of multiple exchange goes through a gentle maximum for ca. 10 at. % Au. At the same time no special catalytic role of the surface sites of a low coordination number is seen. It is speculated that the rollover process may involve similar intermediate species as in alkene hydrogenation. The relative importance of ensemble size vs electronic effects in the Pd-Au alloys for various reactions is discussed.

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

    PubMed Central

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

    2012-01-01

    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. PMID:23230505

  5. Preparation and electrical properties of (Zr,Sn)TiO{sub 4} dielectric thin films by laser ablation

    SciTech Connect

    Nakagawara, Osamu; Toyota, Yuji; Kobayashi, Masato; Yoshino, Yukio; Katayama, Yuzo; Tabata, Hitoshi; Kawai, Tomoji

    1996-11-01

    (Zr,Sn)TiO{sub 4} is considered as a promising dielectric material for microwave devices owing to the temperature stability of capacitance and excellent microwave properties. Preferential (111)-oriented (Zr,Sn)TiO{sub 4} thin film was obtained by an ArF laser ablation. Properties of the crystallized film were as follows; the temperature coefficient of capacitance TCC was 17.6 ppm/C at 3 MHz and the dielectric constant {var_epsilon}{sub r}, 38 in the microwave range of 1GHZ--10GHz. It has turned out that the crystallization of this material is quite effective for improving dielectrical properties. Surface morphologies were observed by atomic force microscope (AFM). Grains grew on the crystallized film at 1 {micro}m x 1 {micro}m size.

  6. 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.

  7. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Sreenivas Puli, Venkata; Kumar Pradhan, Dhiren; Gollapudi, Sreenivasulu; Coondoo, Indrani; Panwar, Neeraj; Adireddy, Shiva; Chrisey, Douglas B.; Katiyar, Ram S.

    2014-11-01

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO3 (BFO) thin films have been deposited on Pt/TiO2/SiO2/Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d33) ~94 pm/V at 0.6 MV/cm. High dielectric constant ~900 and low dielectric loss ~0.25 were observed at room temperature. M-H loops have shown relatively high saturation magnetization ~35 emu/cm3 at a maximum field of H ~20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films.

  8. Interface charge behaviors of BaTiO3 film heterostructures with various crystal orientations

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Ouyang, Jun; Cheng, Hongbo; Yang, Qian; Kang, Limin; Zhang, Hua; Hu, Fangren

    2017-02-01

    Heteroepitaxial BaTiO3 ferroelectric films with (001), (110), and (111) orientations were grown on SrRuO3-buffered SrTiO3 substrates by magnetron sputtering. The leakage current and interface charge behaviors were systematically investigated. Without a discernible orientation-dependence behavior, the leakage current behaviors were all well described by a modified Schottky-contact model. On the basis of this theory, the interface charge state parameters, including dynamic dielectric constant, potential barriers, depletion layer width, effective space-charge density and hole concentration, and their evolution behaviors were analyzed in detail. They all exhibited anisotropic characteristics and were proved to be essentially attributed to the macrophysical properties of BaTiO3 film heterostructures.

  9. Roughness of CdTe thin films grown on glass by hot wall epitaxy

    NASA Astrophysics Data System (ADS)

    Leal, F. F.; Ferreira, S. O.; Menezes-Sobrinho, I. L.; Faria, T. E.

    2005-01-01

    Cadmium telluride films were grown on glass substrates using the hot wall epitaxy (HWE) technique. The samples were polycrystalline with a preferential (111) orientation. Scanning electron micrographs reveal a grain size between 0.1 and 0.5 µm. The surface morphology of the samples was studied by measuring the roughness profile using a stylus profiler. The roughness as a function of growth time and scale size were investigated to determine the growth and roughness exponents, β and α, respectively. From the results we can conclude that the growth surface has a self-affine character with a roughness exponent α equal to 0.69 ± 0.03 and almost independent of growth time. The growth exponent β was equal to 0.38 ± 0.06. These values agree with that determined previously for CdTe(111) films grown on GaAs(100).

  10. Fundamental absorption edges in heteroepitaxial YBiO3 thin films

    NASA Astrophysics Data System (ADS)

    Jenderka, Marcus; Richter, Steffen; Lorenz, Michael; Grundmann, Marius

    2016-09-01

    The dielectric function of heteroepitaxial YBiO3 grown on a-Al2O3 single crystals via pulsed laser deposition is determined in the spectral range from 0.03 eV to 4.5 eV by a simultaneous modeling of the spectroscopic ellipsometry and optical transmission data of YBiO3 films of different thicknesses. The (111)-oriented YBiO3 films are nominally unstrained and crystallize in a defective fluorite-type structure with a F m 3 ¯ m space group. From the calculated absorption spectrum, a direct electronic bandgap energy of 3.6(1) eV and the signature of an indirect electronic transition around 0.5 eV are obtained. These values provide necessary experimental feedback to previous conflicting electronic band structure calculations predicting either a topologically trivial or a non-trivial insulating ground state in YBiO3.

  11. 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.

  12. Element specific and depth-resolved interface magnetism in BiFeO3/La0.67Sr0.33MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Bertinshaw, Joel; Brück, Sebastian; Fritzsche, Helmut; Khaydukov, Yury; Soltwedel, Olaf; Keller, Thomas; Goering, Eberhard; Audehm, Patrick; Hutchison, Wayne; Maran, Ronald; Valanoor, Nagarajan; Klose, Frank; Ulrich, Clemens

    2013-03-01

    In recent years significant research has been conducted to probe the emergent physics of atomically sharp transition metal oxide layered systems. The spin, orbital and charge state at the interface has a drastic impact on the exhibited emergent physics. We have investigated epitaxial bi-layers of multiferroic BiFeO3 (BFO) / ferromagnetic La0.67Sr0.33MnO3 (LSMO). Polarized Neutron Reflectivity conducted at ANSTO, Chalk River, and FRM-II provided the absolute magnetic moment at the interface and X-ray Resonant Magnetic Reflectivity performed at BESSY II provided element specific magnetic information. We determined the precise magnetic properties of the bi-layer interface region, which indicated a region of depleted magnetization extending ~25Å into the LSMO at the interface, despite no FM in the BFO and in contrast to previous results on an inverse LSMO/BFO system. The importance of this result extends to the study and functionality of all strongly correlated thin film systems.

  13. 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.

  14. 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.

  15. Pulsed laser deposition of niobium nitride thin films

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Niobium nitride (NbNx) films were grown on Nb and Si(100) substrates using pulsed laser deposition. NbNx 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 NbNx films from mixed β-Nb2N and cubic δ-NbN phases to single hexagonal β-Nb2N. The substrate temperature affects the preferred orientation of the crystal structure. The structural and electronic, properties of NbNx deposited on Si(100) were also investigated. The NbNx 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 NbNx film morphology and phase.

  16. Magnetoresistance in polycrystalline and epitaxial Fe1-xCoxSi thin films

    NASA Astrophysics Data System (ADS)

    Porter, N. A.; Creeth, G. L.; Marrows, C. H.

    2012-08-01

    Thin films of Fe1-xCoxSi were grown using molecular beam epitaxy on Si(111). These 20-nm-thick films, with compositions x=0 or 0.5, were produced by two methods: the first produced large (111)-textured crystallites of the B20 phase; the second produced phase-pure B20 (111) epilayers. The lattice mismatch with the substrate causes biaxial tensile strain in the layers, greater in the epilayers, that distorts the (111)-oriented material to a rhombohedral form. Magnetotransport measurements show that a combination of additional scattering arising from crystal grain boundaries and strain-free polycrystalline films results in a higher resistivity than for the epitaxial films. Magnetometry for x=0.5 suggests an increase in the ordering temperature in strained films relative to the polycrystalline films of 15±4 K. Moreover, the characteristic linear magnetoresistance, typical of bulk single-crystal material of this composition, is retained in the polycrystalline film but reduced in the epitaxial film. While the bulk properties of these materials are reproduced qualitatively, there are small quantitative modifications, due to the strain, to properties such as band gap, Curie temperature, and magnetoresistance.

  17. Misfit strain driven cation inter-diffusion across an epitaxial multiferroic thin film interface

    NASA Astrophysics Data System (ADS)

    Sankara Rama Krishnan, P. S.; Morozovska, Anna N.; Eliseev, Eugene A.; Ramasse, Quentin M.; Kepaptsoglou, Demie; Liang, Wen-I.; Chu, Ying-Hao; Munroe, Paul; Nagarajan, V.

    2014-02-01

    Cation intermixing at functional oxide interfaces remains a highly controversial area directly relevant to interface-driven nanoelectronic device properties. Here, we systematically explore the cation intermixing in epitaxial (001) oriented multiferroic bismuth ferrite (BFO) grown on a (001) lanthanum aluminate (LAO) substrate. Aberration corrected dedicated scanning transmission electron microscopy and electron energy loss spectroscopy reveal that the interface is not chemically sharp, but with an intermixing of ˜2 nm. The driving force for this process is identified as misfit-driven elastic strain. Landau-Ginzburg-Devonshire-based phenomenological theory was combined with the Sheldon and Shenoy formula in order to understand the influence of boundary conditions and depolarizing fields arising from misfit strain between the LAO substrate and BFO film. The theory predicts the presence of a strong potential gradient at the interface, which decays on moving into the bulk of the film. This potential gradient is significant enough to drive the cation migration across the interface, thereby mitigating the misfit strain. Our results offer new insights on how chemical roughening at oxide interfaces can be effective in stabilizing the structural integrity of the interface without the need for misfit dislocations. These findings offer a general formalism for understanding cation intermixing at highly strained oxide interfaces that are used in nanoelectronic devices.

  18. Effects of Various RF Powers on CdTe Thin Film Growth Using RF Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Alibakhshi, Mohammad; Ghorannevis, Zohreh

    2016-09-01

    Cadmium telluride (CdTe) film was deposited using the magnetron sputtering system onto a glass substrate at various deposition times and radio frequency (RF) powers. Ar gas was used to generate plasma to sputter the CdTe atoms from CdTe target. Effects of two experimental parameters of deposition time and RF power were investigated on the physical properties of the CdTe films. X-ray Diffraction (XRD) analysis showed that the films exhibited polycrystalline nature of CdTe structure with the (111) orientation as the most prominent peak. Optimum condition to grow the CdTe film was obtained and it was found that increasing the deposition time and RF power increases the crystallinity of the films. From the profilometer and XRD data's, the thicknesses and crystal sizes of the CdTe films increased at the higher RF power and the longer deposition time, which results in affecting the band gap as well. From atomic force microscopy (AFM) analysis we found that roughnesses of the films depend on the deposition time and is independent of the RF power.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. [Preparation and characterization of poly-Si films on different topography substrates by AIC].

    PubMed

    Wang, Cheng-Long; Fan, Duo-Wang; Liu, Hong-Zhong; Zhang, Fu-Jia; Xing, Da; Liu, Song-Hao

    2009-03-01

    Polycrystalline silicon (poly-Si) thin-films were made on planar and textured glass substrates by aluminum-induced crystallization (AIC) of in situ amorphous silicon (a-Si) deposited by DC-magnetron. The poly-Si films were characterized by Raman spectroscopy, X-ray diffraction (XRD) and atomic force microscopy (AFM). A narrow and symmetrical Ranman peak at the wave number of about 521 cm(-1) was observed for all samples, indicating that the films were fully crystallized. XRD results show that the crystallites in the authors' AIC poly-Si films were preferably (111) oriented. The measurement of full width at half maximum (FWHW) of (111) XRD peaks showed that the quality of the films was affected by the a-Si deposition temperature and the surface morphology of the glass substrates. It is likely that an a-Si deposition temperature of 200 degrees C seems to be ideal for the preparation of poly-Si films by AIC.

  4. Measurements of magnetostriction constants of epitaxial garnet films by double-crystal x-ray diffraction

    SciTech Connect

    Mada, J.; Yamaguchi, K.

    1982-01-01

    Magnetostriction constants lambda/sub 111/ have been determined at room temperature with the double-crystal x-ray diffraction technique by measuring a small change in the lattice parameter. Measurements were carried out for epitaxial garnet films of Y/sub 3/Fe/sub 5/O/sub 12/ and Sm/sub 0.85/Tm/sub 2.15/Fe/sub 5/O/sub 12/ grown on (111) oriented Gd/sub 3/Ga/sub 5/O/sub 12/ substrates; and also for flux-grown bulk single crystal of Y/sub 3/Fe/sub 5/O/sub 12/. Values of lambda/sub 111/ obtained were -1.7 x 10/sup -6/ for film and -3.0 x 10/sup -6/ for bulk crystal. lambda/sub 111/ of Sm/sub 0.85/Tm/sub 2.15/Fe/sub 5/O/sub 12/ was -5.0 x 10/sup -6/. The discrepancy in lambda/sub 111/ values between film and bulk Y/sub 3/Fe/sub 5/O/sub 12/ is almost accounted for by the fact that the film can deform only perpendicular to the film plane due to the shear force of the substrate. It has been experimentally demonstrated that lambda/sub 111/ does not depend on film thickness or lattice mismatch, which is consistent with the present analysis.

  5. Exploring Polarization Rotation Phase Instabilities in Super-Tetragonal BiFeO3 Epitaxial Thin Films and Their Technological Implications

    DOE PAGES

    Cao, Ye; Yang, Mr. Shuzhen; Jesse, Stephen; ...

    2016-01-01

    Many functional properties of ferroelectrics are underlain by structural instabilities, which render these materials very susceptible to small alternating applied fields (electric, mechanical, etc.) through certain constitutive coupling relations, e.g., elastic compliance and piezoelectric response, and often such instabilities can be shifted by static applied fields thus meaning tunable dynamic properties. Structural instabilities are naturally accommodated on the brink of morphotropic phase boundaries (MPB s) where multiple phases of small energy difference coexist in different crystallographic forms. Canonical MPB is realized through compositional mixture, as is typically exemplified by Pb(Zr1-xTix)O3 solid solutions and relaxor ferroelectrics of (1-x)PbMg1/3Nb2/3O3-xPbTiO3. More recently, amore » strain-driven MPB has been discovered in BiFeO3 (BFO) thin films epitaxially grown on LaAlO3 (LAO) crystal substrates (which imposes about -4.5% in-plane strains). Such an MPB is in between a rhombohedral (R) phase that bulk BFO exhibits and a so-called super-tetragonal (T) phase, which name hints at its giant lattice axial ratio (c/a ~ 1.23) and accordingly high electric polarization (~1.5 C m-2). The discovery of an MPB in BFO has revealed another facet of this multiferroic system, further adding opportunities to its many exotic functionalities such as domain wall conduction, magnetoelectric and photovoltaic effects As with other MPB s, large electric-field induced strains as well as more underlying lattice softening effects are observed near this MPB promising piezoelectric-based applications. In addition, T-phase BFO itself shows distinct properties, e.g., electronic band gap and optical absorption, from the R-phase and the resultant switching effects between them may also be exploitable. However, unlike conventional ferroelectric oxides where the phases across an MPB usually have subtle difference caused by rotations of an ion off-centering polarization, the BFO

  6. Exploring Polarization Rotation Phase Instabilities in Super-Tetragonal BiFeO3 Epitaxial Thin Films and Their Technological Implications

    SciTech Connect

    Cao, Ye; Yang, Mr. Shuzhen; Jesse, Stephen; Kravchenko, Ivan I; Yu, Pu; Chen, L. Q.; Kalinin, Sergei V; Wisinger, Nina Balke; Li, Qian

    2016-01-01

    Many functional properties of ferroelectrics are underlain by structural instabilities, which render these materials very susceptible to small alternating applied fields (electric, mechanical, etc.) through certain constitutive coupling relations, e.g., elastic compliance and piezoelectric response, and often such instabilities can be shifted by static applied fields thus meaning tunable dynamic properties. Structural instabilities are naturally accommodated on the brink of morphotropic phase boundaries (MPB s) where multiple phases of small energy difference coexist in different crystallographic forms. Canonical MPB is realized through compositional mixture, as is typically exemplified by Pb(Zr1-xTix)O3 solid solutions and relaxor ferroelectrics of (1-x)PbMg1/3Nb2/3O3-xPbTiO3. More recently, a strain-driven MPB has been discovered in BiFeO3 (BFO) thin films epitaxially grown on LaAlO3 (LAO) crystal substrates (which imposes about -4.5% in-plane strains). Such an MPB is in between a rhombohedral (R) phase that bulk BFO exhibits and a so-called super-tetragonal (T) phase, which name hints at its giant lattice axial ratio (c/a ~ 1.23) and accordingly high electric polarization (~1.5 C m-2). The discovery of an MPB in BFO has revealed another facet of this multiferroic system, further adding opportunities to its many exotic functionalities such as domain wall conduction, magnetoelectric and photovoltaic effects As with other MPB s, large electric-field induced strains as well as more underlying lattice softening effects are observed near this MPB promising piezoelectric-based applications. In addition, T-phase BFO itself shows distinct properties, e.g., electronic band gap and optical absorption, from the R-phase and the resultant switching effects between them may also be exploitable. However, unlike conventional ferroelectric oxides where the phases across an MPB usually have subtle difference caused by rotations of an ion off-centering polarization, the BFO system

  7. Reduced ferroelectric coercivity in multiferroic Bi0.825Nd0.175FeO3 thin film

    NASA Astrophysics Data System (ADS)

    Yuan, G. L.; Or, Siu Wing; Chan, Helen Lai Wa; Liu, Z. G.

    2007-01-01

    Bi0.825Nd0.175FeO3 (BNFO) thin film is grown on Pt /TiO2/SiO2/Si substrate by pulsed laser deposition, and its multiferroic properties are compared with those of BiFeO3 (BFO) thin film. With limited Fe2+ ions and its twinborn oxygen vacancies, both samples show low dielectric losses of <0.026 at 100Hz and high maximum ferroelectric polarizations of ˜34μC /cm2. The ferroelectric coercive field of BNFO is reduced by ˜40%, reaching a low value of 235kV/cm, compared to that of BFO due to the increased ratio of 180° and curved ferroelectric domains to total ferroelectric domains and better nucleation of the ferroelectric domains at the BNFO/Pt interface. The Raman scattering spectra confirm that the ferroelectric polarizations of both samples originate in the stereochemical activity of the Bi lone electron pair. Weak ferromagnetism is observed in both samples as a result of the limited amount of Fe2+ ions and γ-Fe2O3 impurity.

  8. 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.

  9. 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.

  10. Single orientation graphene synthesized on iridium thin films grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Dangwal Pandey, A.; Krausert, K.; Franz, D.; Grânäs, E.; Shayduk, R.; Müller, P.; Keller, T. F.; Noei, H.; Vonk, V.; Stierle, A.

    2016-08-01

    Heteroepitaxial iridium thin films were deposited on (0001) sapphire substrates by means of molecular beam epitaxy, and subsequently, one monolayer of graphene was synthesized by chemical vapor deposition. The influence of the growth parameters on the quality of the Ir films, as well as of graphene, was investigated systematically by means of low energy electron diffraction, x-ray reflectivity, x-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Our study reveals (111) oriented iridium films with high crystalline quality and extremely low surface roughness, on which the formation of large-area epitaxial graphene is achieved. The presence of defects, like dislocations, twins, and 30° rotated domains in the iridium films is also discussed. The coverage of graphene was found to be influenced by the presence of 30° rotated domains in the Ir films. Low iridium deposition rates suppress these rotated domains and an almost complete coverage of graphene was obtained. This synthesis route yields inexpensive, air-stable, and large-area graphene with a well-defined orientation, making it accessible to a wider community of researchers for numerous experiments or applications, including those which use destructive analysis techniques or irreversible processes. Moreover, this approach can be used to tune the structural quality of graphene, allowing a systematic study of the influence of defects in various processes like intercalation below graphene.

  11. Remote plasma assisted growth of graphene films: structure and physical properties

    NASA Astrophysics Data System (ADS)

    Rouvimov, Sergei; Nandamuri, Gopichand; Solanki, Raj

    2010-03-01

    The unique electrical properties of graphene, in particular ballistic transport and tunable transport properties have opened up exciting possibilities for this material as a replacement for silicon [1-2]. While graphene is commonly produced in research laboratories by mechanical exfoliation of highly oriented pyrolytic graphite, mass production of graphene-based devices requires technological approach to synthesize thin graphene films such as chemical vapor deposition. In present work, single and multiple layers of graphene films were grown on (111) oriented single crystals of nickel and polycrystalline nickel films using remote plasma assisted chemical vapor deposition. Remote plasma was employed to eliminate the effect of the electrical field on the orientation of the grown graphene films, as well as reduce the growth temperature compared to conventional chemical vapor deposition. The electrical and optical properties, including high resolution transmission electron microscopy of these films, suggest that this approach is both versatile and scalable for potential large area optoelectronic applications. [4pt] [1] T. Ohta, et al. Science 2006, 313, 951- 954 [0pt] [2] Y. B, Zhang, et al. Nature 2005, 438, 201- 204

  12. 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.

  13. 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.

  14. Contributions to the dielectric losses of textured SrTiO3 thin films with Pt electrodes

    NASA Astrophysics Data System (ADS)

    Lu, Jiwei; Schmidt, Steffen; Ok, Young-Woo; Keane, Sean P.; Stemmer, Susanne

    2005-09-01

    The factors controlling low-frequency (1 MHz) dielectric losses of textured SrTiO3 thin films deposited by radio-frequency magnetron sputtering on platinized sapphire substrates were investigated. In particular, the influence of film texture, phase transformations, applied bias field, temperature, and annealing atmospheres was studied. Films that were (111) textured showed a phase transformation at ~150 K, whereas films that were predominantly (110) oriented did not exhibit a phase transformation in the measured temperature range (100-300 K). Two major contributions to the dielectric losses were identified: a low-temperature loss increase for the (111) oriented film, which could be suppressed by an applied bias field, and a loss peak at ~250 K (at 1 MHz), which was strongly frequency-dependent and likely associated with a relaxing defect. The low-temperature loss mode was related to the appearance of a phase transformation and contributed to the dielectric losses even at temperatures that were more than 100 K above the phase transformation. In contrast to the leakage properties of the films, which were strongly dependent on annealing atmospheres, annealing under reducing conditions had no significant influence on any of the observed loss modes. Possible origins of the different loss contributions were discussed.

  15. N-type control of single-crystal diamond films by ultra-lightly phosphorus doping

    NASA Astrophysics Data System (ADS)

    Kato, Hiromitsu; Ogura, Masahiko; Makino, Toshiharu; Takeuchi, Daisuke; Yamasaki, Satoshi

    2016-10-01

    A wide impurity doping range of p- and n-type diamond semiconductors will facilitate the development of various electronics. This study focused on producing n-type diamond with ultra-lightly impurity doping concentrations. N-type single-crystal diamond films were grown on (111)-oriented diamond substrates by phosphorus doping using the optimized doping conditions based on microwave plasma-enhanced chemical vapor deposition with a high magnetron output power of 3600 W. The surface morphology was investigated by an optical microscopy using the Nomarski prism and confocal laser microscopy, and the phosphorus concentration was estimated by a secondary ion mass spectrometry. The phosphorus concentration was reproducibly controlled to between 2 × 1015 and 3 × 1017 cm-3 using a standard mass flow controller, and the average incorporation efficiency was around 0.1%. The electrical properties of the films were characterized by the Hall effect measurements as a function of temperature over a wide range from 220 to 900 K. N-type conductivity with thermal activation from a phosphorus donor level at around 0.57 eV was clearly observed for all the phosphorus-doped diamond films. The electron mobility of the film with a phosphorus concentration of 2 × 1015 cm-3 was recorded at 1060 cm2/V s at 300 K and 1500 cm2/V s at 225 K.

  16. Dynamic conversion of optical modes in magnetic garnet films induced by resonances of periodic stripe domains

    NASA Astrophysics Data System (ADS)

    Winkler, H. P.; Doetsch, H.; Luehrmann, B.; Sure, S.

    1994-09-01

    Magnetic garnet films of composition (Y,Bi)3(Fe,Al)5O12 are grown by liquid phase epitaxy on (111) oriented substrates of Gd3Ga5O12. They support periodic lattices of parallel stripe domains. A simple strip antenna is used to excite the domain wall resonance and the two branches of the domain resonance in the frequency range up to 5 GHz. The resonance frequencies and the dynamic components of the magnetization are calculated using a hybridization model. Good agreement between calculated and measured resonance frequencies is obtained if the quality factor of the film is larger than 0.6. Optical modes are coupled into the waveguiding film. The excited domain resonances cause dynamic conversion of transverse electric and transverse magnetic modes by the Faraday and the Cotton-Mouton effects. Mode coupling and conversion are calculated by the perturbation theory. The dynamic conversion efficiencies are measured at the fundamental and the first harmonic frequency and at zero diffraction order as a function of the static induction applied in the film plane parallel to the stripes. Conversion efficiencies up to 18% are achieved at a frequency of 2.8 GHz. From the experimental data the precession angles are derived.

  17. Single cuprous oxide films synthesized by radical oxidation at low temperature for PV application.

    PubMed

    Zang, Zhigang; Nakamura, Atsushi; Temmyo, Jiro

    2013-05-06

    Cuprous oxide (Cu(2)O) films synthesis by radical oxidation with nitrogen (N(2)) plasma treatment and different RF power at low temperature (500 °C) are studied in this paper. X-ray diffraction measurements show that synthesized Cu(2)O thin films grow on c-sapphire substrate with preferred (111) orientation. With nitrogen (N(2)) plasma treatment, the optical bandgap energy is increased from 1.69 to 2.42 eV, when N(2) plasma treatment time is increased from 0 min to 40 min. Although the hole density is increased from 10(14) to 10(15) cm(-3) and the resistivity is decreased from 1879 to 780 Ω cm after N(2) plasma treatment, the performance of Cu(2)O films is poorer compared to that of Cu(2)O using RF power of 0. The fabricated ZnO/Cu(2)O solar cells based on Cu(2)O films with RF power of 0 W show a good rectifying behavior with a efficiency of 0.02%, an open-circuit voltage of 0.1 V, and a fill factor of 24%.

  18. Microstructure, electrical and magnetic properties of Ce-doped BiFeO3 thin films

    NASA Astrophysics Data System (ADS)

    Quan, Zuci; Liu, Wei; Hu, Hao; Xu, Sheng; Sebo, Bobby; Fang, Guojia; Li, Meiya; Zhao, Xingzhong

    2008-10-01

    Bi1-xCexFeO3 (x =0, 0.05, 0.1, 0.15, and 0.20) (BCFO) thin films were deposited on Pt/TiN/Si3N4/Si and fluorine-doped SnO2 glass substrates by sol-gel technique, respectively. The effect of Ce doping on the microstructure, electrical and magnetic properties of BCFO films was studied. Compared to counterparts of BiFeO3 (BFO) film, the fitted Bi 4f7/2, Bi 4f5/2, Fe 2p3/2, Fe 2p1/2, and O 1s peaks for Bi0.8Ce0.2FeO3 film shift toward higher binding energy regions by amounts of 0.33, 0.29, 0.43, 0.58, and 0.49 eV, respectively. Raman redshifts of 2-4 cm-1 and shorter phonon lifetimes for the Bi0.8Ce0.2FeO3 film might be related to anharmonic interactions among Bi-O, Ce-O, (Bi, Ce)-O, and Fe-O bonds in the distorted oxygen octahedron. Compared to the pure counterparts, the dielectric and ferroelectric properties of the Bi0.8Ce0.2FeO3 film are improved due to the decreased oxygen vacancies by the stabilized oxygen octahedron. Current density values for the BFO and Bi0.8Ce0.2FeO3 film capacitors are 9.89×10-4 and 5.86×10-5 A/cm2 at 10 V, respectively. The current density-applied voltage characteristics indicate that the main conduction mechanism for the BCFO capacitors is the interface-controlled Schottky emission. Both the in-plane and out-of-plane magnetization-magnetic field hysteresis loops reveal that the saturation magnetization values of the BCFO films increase with increasing the Ce concentration. The enhanced magnetic properties for the BCFO films might be attributed to the presence of Fe2+ caused by oxygen vacancies, the suppressed spiral spin structure, and/or the increased canting angle induced by Ce doping.

  19. Deposition of epitaxially oriented films of cubic silicon carbide on silicon by laser ablation: Microstructure of the silicon-silicon- carbide interface

    NASA Astrophysics Data System (ADS)

    Rimai, L.; Ager, R.; Weber, W. H.; Hangas, J.; Samman, A.; Zhu, W.

    1995-06-01

    Excimer laser ablation has been used to deposit epitaxial films of β-SiC on single-crystal Si wafers, in a vacuum, at substrate temperatures between 1050 and 1250 °C. Such films can be grown by ablating ceramic SiC, carbon, or alternating silicon and carbon targets at a range of growth rates. X-ray θ-2θ diffraction shows the presence of strong, sharp reflections from crystal planes parallel to the substrate, 200 and 400 for [100] substrates and 111 and 222 for [111] oriented substrates. Wrong reflections, such as 111 for [100] substrates, are extremely weak or absent, indicating alignment with the substrates. The characterization of these films by a number of techniques is discussed. In all cases the film-substrate interface shows a characteristic microstructure of cavities in the Si substrate, similar to that observed for the carbonization layer initially formed as a precursor for chemical-vapor deposition of SiC films on Si. This implies that the initial film growth, for all cases, involves chemical reaction of the Si substrate with the carbon in the plume as well as transport through the growing film.

  20. Mass transport and electrode accessibility through periodic self-assembled nanoporous silica thin films.

    PubMed

    Wei, Ta-Chen; Hillhouse, Hugh W

    2007-05-08

    Ordered nanoporous silica films have attracted great interest for their potential use to template nanowires for photovoltaics and thermoelectrics. However, it is crucial to develop films such that an electrode under the nanoporous film is accessible to solution species via facile mass transport through well-defined pores. Here, we quantitatively measure the electrode accessibility and the effective species diffusivity for nearly all the known nanoporous silica film structures formed by evaporation-induced self-assembly upon dip-coating or spin-coating. Grazing-angle of incidence small-angle X-ray scattering was used to verify the nanoscale structure of the films and to ensure that all films were highly ordered and oriented. Electrochemical impedance spectroscopy (EIS) was then used to assess the transport properties. A model has been developed that separates the electrode/film kinetics and the film transport properties from the film/solution interface and bulk solution effects. Accounting for this, the accessible area of the nanoporous film coated FTO electrode (1-theta) is obtained from the high-frequency data, while the effective diffusivity of the ferrocene dimethanol (D(FDM)) redox couple is obtained from intermediate frequencies. It was found that the degree of order and orientation in the film, in addition to the symmetry/topology, is a dominant factor that determines these two key parameters. The EIS data show that the (211) oriented double gyroid, (110) oriented distorted body center cubic, and (211) distorted primitive cubic silica films have significant accessibility (larger than 26% of geometric area). However, the double-gyroid films showed the highest diffusivity by over an order of magnitude. Both the (10) oriented 2D hexagonal and (111) oriented rhombohedral films were found to be highly blocking with only small accessibility due to microporosity. The impedance data were also collected to study the stability of the nanoporous silica films in aqueous

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

    DOE PAGES

    A. J. Littlejohn; Zhang, L. H.; Lu, T. -M.; ...

    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

  2. Origin of soft-mode stiffening and reduced dielectric response in SrTiO3 thin films

    NASA Astrophysics Data System (ADS)

    Ostapchuk, T.; Petzelt, J.; Železný, V.; Pashkin, A.; Pokorný, J.; Drbohlav, I.; Kužel, R.; Rafaja, D.; Gorshunov, B. P.; Dressel, M.; Ohly, Ch.; Hoffmann-Eifert, S.; Waser, R.

    2002-12-01

    The problem of the reduced dielectric response in thin films of high-permittivity materials is analyzed by studying the soft-mode response in several SrTiO3 thin films by means of Fourier transform far infrared, monochromatic submillimeter, and micro-Raman spectroscopies. A 300-nm-thick metalorganic chemical vapor deposition film, quasiepitaxially grown on a (0001) sapphire substrate with a perfect <111> orientation, displays a ferroelectric transition near 125 K induced by a tensile residual stress, appearing apparently simultaneously with the antiferrodistortive transition. On the other hand, polycrystalline chemical solution deposition films grown on (0001) sapphire, and also tensile stressed, show a harder soft mode response without the appearance of macroscopic ferroelectricity. This effect, which increases with the film thickness, is explained by a strong depolarizing field induced by the percolated porosity and cracks (in the 10-nm scale) along the boundaries of columnar grains (normal to the probe field direction). Brick-wall model calculations showed that 0.2 vol. % of such a porosity type reduces the permittivity from 30000 to less than 1000. The activation of the forbidden IR modes in the Raman spectra in the whole 80-300-K temperature range studied is explained by the effect of polar grain boundaries, in analogy with the bulk ceramics.

  3. Thin films of rare-earth (Y, La, Ce, Pr, Nd, Sm) oxides formed by the spray-ICP technique

    NASA Astrophysics Data System (ADS)

    Suzuki, M.; Kagawa, M.; Syono, Y.; Hirai, T.

    1991-07-01

    Thin films of Y 2O 3, La 2O 3, CeO 2, PrO 2, Nd 2O 3 and Sm 2O 3 were synthesized by injecting ultrasonically atomized metal nitrate solutions into a high temperature inductively coupled RF plasma above 5000 K generated under atmospheric pressure (the spray-ICP technique). Fused quartz plates and single crystal sapphire plates giving no background X-ray reflection peaks were used as substrates. About 0.4 μm thick transparent films could be prepared by 10 min of running. The films of CeO 2 and PrO 2, both belonging to the cubic flourite type, revealed (100) and (111) orientations, respectively. With the remaining oxides having A (hexagonal), B (monoclinic) and C (cubic) rare-earth structures, film orientations were A (001) for La 2O 3, A (001)+C (111) for Nd 2O 3, and C (111) for Y 2O 3. Sm 2O 3 films were composed of a phase with C (111) and an extra phase with an orientation close to (001) of A-Sm 2O 3 or its equivalent, (20 overline1) of B-Sm 2O 3.

  4. 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

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

    PubMed

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

    2011-08-08

    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∕cm(3) at 100 Oe under the application of external electric fields (E) across interdigital electrodes in BiFeO(3) (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).

  6. Optimization of Deposition Process and Microscopic Characterization of Highly Oriented Aluminum Nitride Thin Films for Bimorph Structures of Piezoelectric Tunable Capacitors

    NASA Astrophysics Data System (ADS)

    Nagano, Toshihiko; Nishigaki, Michihiko; Itaya, Kazuhiko; Kawakubo, Takashi

    2009-02-01

    Film deposition with RF sputtering to control residual stress in aluminum nitride (AlN) thin films has been investigated to fabricate the bimorph actuator for a piezoelectric tunable capacitor with low-voltage operation. The effects of conditions in sputtering and surface cleaning were studied both to obtain a preferable film orientation for piezoelectric actuation and to suppress structural deformation of the cantilever due to the residual stress in films. Microscopic analysis revealed that (0001)-oriented AlN and (111)-oriented Al films were epitaxially grown at each interface in the bimorph structure. The current-voltage (I-V) measurements showed a leakage current of less than 5 ×10-5 A m-2 in 500-nm thick AlN films up to 30 V. The effect of optimization of process parameters was demonstrated by the capacitance-voltage (C-V) characteristics of the folded-beam tunable capacitor, in which the suppression of residual stress in piezoelectric layers was shown to be effective to obtain low-voltage operation.

  7. Optical and electrical properties of copper-doped nano-crystallite CdO thin films

    NASA Astrophysics Data System (ADS)

    Dakhel, A. A.

    2014-05-01

    Thin films of Cu-doped CdO (CdO:Cu) with different Cu% content were prepared in high vacuum on glass and Si substrates. The samples were characterised X-ray diffraction (XRD), optical spectroscopy, scanning electron microscope (SEM), and dc-electrical measurements. The XRD study reveals the formation of single crystalline phase CdO:Cu of CdO structure with a preferential [111] orientation. However, with increasing of Cu% content, the crystal structure was gradually deteriorated. SEM study shows formation of granular structure with rice shape grains of average size ˜500 nm. The optical study shows that Cu doping increased the films transparency with a slight blueshift for the bandgap. The calculated optical constants for pure and Cu-doped CdO were analysed with Forouhi-Bloomer (FB), Wemple-Didomenico (WD), and Spitzer-Fan (SF) models. Good agreements were obtained between electrical and optical (through SF model) measurements. The electrical measurements show that the utmost enhancement in mobility (82.5 cm2/V s) and conductivity (1428.6 S/cm) was found with 2.3% Cu sample. The optoelectronic study was analysed through the available BGW and BGN models that show close theoretical to the experimental results. In general, the films of CdO prepared with light Cu doping have optical and electrical characteristics suitable for various applications in material sciences and optoelectronic devices.

  8. 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)

  9. On the Discontinuity of Polycrystalline Silicon Thin Films Realized by Aluminum-Induced Crystallization of PECVD-Deposited Amorphous Si

    NASA Astrophysics Data System (ADS)

    Pan, Qingtao; Wang, Tao; Yan, Hui; Zhang, Ming; Mai, Yaohua

    2017-04-01

    Crystallization of glass/Aluminum (50, 100, 200 nm) /hydrogenated amorphous silicon (a-Si:H) (50, 100, 200 nm) samples by Aluminum-induced crystallization (AIC) is investigated in this article. After annealing and wet etching, we found that the continuity of the polycrystalline silicon (poly-Si) thin films was strongly dependent on the double layer thicknesses. Increasing the a-Si:H/Al layer thickness ratio would improve the film microcosmic continuity. However, too thick Si layer might cause convex or peeling off during annealing. Scanning electron microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX) are introduced to analyze the process of the peeling off. When the thickness ratio of a-Si:H/Al layer is around 1 to 1.5 and a-Si:H layer is less than 200 nm, the poly-Si film has a good continuity. Hall measurements are introduced to determine the electrical properties. Raman spectroscopy and X-ray diffraction (XRD) results show that the poly-Si film is completely crystallized and has a preferential (111) orientation.

  10. Misfit Strain Relaxation of Ferroelectric PbTiO3/LaAlO3 (111) Thin Film System

    PubMed Central

    Xu, Y. B.; Tang, Y. L.; Zhu, Y. L.; Liu, Y.; Li, S.; Zhang, S. R.; Ma, X. L.

    2016-01-01

    Ferroelectric thin films grown on high index substrates show unusual structural and switching dynamics due to their special strain states. Understanding the misfit relaxation behavior is crucial to facilitate the high index thin film growth with improved quality. In this paper, ferroelectric PbTiO3 thin films were grown on LaAlO3 (111) substrates by pulsed laser deposition technique. The microstructures were investigated by combinations of conventional and aberration-corrected transmission electron microscopy. Diffraction contrast analysis and high resolution imaging reveal that high density interfacial dislocations were distributed at the interfaces. These dislocations have mixed character with Burgers vectors of a <110> and line directions of <112>. The edge components of the dislocations, with the Burgers vectors parallel to the interface, accommodate the lattice mismatch and are the main contributor to the misfit relaxation of this system. The formation mechanism of these dislocations is proposed and discussed to elucidate the novel mismatch relaxation behavior of <111> oriented perovskite films. PMID:27725752

  11. On the Discontinuity of Polycrystalline Silicon Thin Films Realized by Aluminum-Induced Crystallization of PECVD-Deposited Amorphous Si

    NASA Astrophysics Data System (ADS)

    Pan, Qingtao; Wang, Tao; Yan, Hui; Zhang, Ming; Mai, Yaohua

    2017-01-01

    Crystallization of glass/Aluminum (50, 100, 200 nm) /hydrogenated amorphous silicon (a-Si:H) (50, 100, 200 nm) samples by Aluminum-induced crystallization (AIC) is investigated in this article. After annealing and wet etching, we found that the continuity of the polycrystalline silicon (poly-Si) thin films was strongly dependent on the double layer thicknesses. Increasing the a-Si:H/Al layer thickness ratio would improve the film microcosmic continuity. However, too thick Si layer might cause convex or peeling off during annealing. Scanning electron microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX) are introduced to analyze the process of the peeling off. When the thickness ratio of a-Si:H/Al layer is around 1 to 1.5 and a-Si:H layer is less than 200 nm, the poly-Si film has a good continuity. Hall measurements are introduced to determine the electrical properties. Raman spectroscopy and X-ray diffraction (XRD) results show that the poly-Si film is completely crystallized and has a preferential (111) orientation.

  12. Misfit Strain Relaxation of Ferroelectric PbTiO3/LaAlO3 (111) Thin Film System

    NASA Astrophysics Data System (ADS)

    Xu, Y. B.; Tang, Y. L.; Zhu, Y. L.; Liu, Y.; Li, S.; Zhang, S. R.; Ma, X. L.

    2016-10-01

    Ferroelectric thin films grown on high index substrates show unusual structural and switching dynamics due to their special strain states. Understanding the misfit relaxation behavior is crucial to facilitate the high index thin film growth with improved quality. In this paper, ferroelectric PbTiO3 thin films were grown on LaAlO3 (111) substrates by pulsed laser deposition technique. The microstructures were investigated by combinations of conventional and aberration-corrected transmission electron microscopy. Diffraction contrast analysis and high resolution imaging reveal that high density interfacial dislocations were distributed at the interfaces. These dislocations have mixed character with Burgers vectors of a <110> and line directions of <112>. The edge components of the dislocations, with the Burgers vectors parallel to the interface, accommodate the lattice mismatch and are the main contributor to the misfit relaxation of this system. The formation mechanism of these dislocations is proposed and discussed to elucidate the novel mismatch relaxation behavior of <111> oriented perovskite films.

  13. Domain structure and in-plane switching in a highly strained Bi0.9Sm0.1FeO3 film

    NASA Astrophysics Data System (ADS)

    Chen, Weigang; Ren, Wei; You, Lu; Yang, Yurong; Chen, Zuhuang; Qi, Yajun; Zou, Xi; Wang, Junling; Sritharan, Thirumany; Yang, Ping; Bellaiche, L.; Chen, Lang

    2011-11-01

    We report the domain structure and ferroelectric properties of a 32 nm-thick Bi0.9Sm0.1FeO3 film epitaxially grown on a LaAlO3 (LAO) substrate. This film exhibits a monoclinic Mc phase, with its monoclinic distortion and anisotropy of in-plane (IP) lattice parameters being both smaller than those of pure BiFeO3 (BFO) grown on LaAlO3. Polarization hysteresis loops measured using a quasi-planar capacitor show an in-plane polarization up to 30 μC/cm2. Piezoresponse force microcopy demonstrates that a 180° in-plane polarization switching accompanied by a 90° domain wall rotation takes place after electric poling. First-principles calculations suggest the differences between highly strained Sm-substituted and pure BiFeO3.

  14. 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.

  15. 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

  16. 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

  17. 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

    2016-07-20

    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.

  18. 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.

  19. Low-temperature MOCVD growth of oriented PbZr{sub x}Ti{sub 1-x}O{sub 3} thin films on Si substrates.

    SciTech Connect

    Chen, N.

    1998-05-08

    Polycrystalline Pb(Zr{sub 0.6}Ti{sub 0.4})O{sub 3} (PZT) thin films, 3000-6000 {angstrom} thick, have been grown by metal-organic chemical vapor deposition (MOCVD) on (111)Pt/Ti/SiO{sub 2}/Si substrates at temperatures as low as 450-525 C. Random and (111)-oriented, or occasionally (100)-oriented, PZT films can be deposited directly on (111)Pt/Ti/SiO{sub 2}/Si. In addition, highly (100)-oriented films can be deposited consistently by using 150-250 {angstrom} thick (100)-oriented PbTiO{sub 3} (PT) or TiO{sub 2} as a template. Films were characterized by X-ray diffraction, electron microscopy, and electrical measurements. The as-grown (100)-oriented films on (111)Pt/TiSiO{sub 2}/Si substrates exhibited dielectric constants ({var_epsilon}{sub r}) of up to 600, remnant polarization (P{sub r}) of 40 {micro}C/cm{sup 2}, coercive field of 55 kV/cm, and breakdown field of 2-6 x 10{sub 7} V/m.

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

    SciTech Connect

    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 first 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

  2. 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

  3. 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.

  4. High-temperature large-gap quantum anomalous Hall insulating state in ultrathin double perovskite films

    NASA Astrophysics Data System (ADS)

    Baidya, Santu; Waghmare, Umesh V.; Paramekanti, Arun; Saha-Dasgupta, Tanusri

    2016-10-01

    Towards the goal of realizing topological phases in thin films of correlated oxide and heterostructures, we propose here a quantum anomalous Hall insulator (QAHI) in ultrathin films of double perovskites based on mixed 3 d -5 d or 3 d -4 d transition-metal ions, grown along the [111] direction. Considering the specific case of ultrathin Ba2FeReO6 , we present a theoretical analysis of an effective Hamiltonian derived from first principles. We establish that a strong spin-orbit coupling at the Re site, t2 g symmetry of the low-energy d bands, polarity of its [111] orientation of perovskite structure, and mixed 3 d -5 d chemistry results in room temperature magnetism with a robust QAHI state of Chern number C =1 and a large band gap. We uncover and highlight a nonrelativistic orbital Rashba-type effect in addition to the spin-orbit coupling, that governs this QAHI state. With a band gap of ˜100 meV in electronic structure and magnetic transition temperature Tc˜300 K estimated by Monte Carlo simulations, our finding of the QAHI state in ultrathin Ba2FeReO6 is expected to stimulate experimental verification along with possible practical applications of its dissipationless edge currents.

  5. 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.

  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. 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.

  8. 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%.

  9. Epitaxial growth of iridate pyrochlore Nd2Ir2O7 films

    SciTech Connect

    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 polycrystalline Ir nanocrystals.

  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. Spin-Relaxation Dynamics of E' Centers at High Density in SiO2 Thin Films for Single-Spin Tunneling Force Microscopy

    NASA Astrophysics Data System (ADS)

    Ambal, K.; Payne, A.; Waters, D. P.; Williams, C. C.; Boehme, C.

    2015-08-01

    The suitability of the spin dynamics of paramagnetic silicon dangling bonds (E' centers) in high-E'-density amorphous silicon dioxide (SiO2 ) as probe spins for single-spin tunneling force microscopy (SSTFM) is studied. SSTFM is a spin-selection-rule-based scanning-probe single-spin readout concept. Following the synthesis of SiO2 thin films on (111)-oriented crystalline-silicon substrates with room-temperature stable densities of [E'] >5 ×1018 cm-3 throughout the 60-nm thin film, pulsed electron paramagnetic resonance spectroscopy is conducted on the E' centers at temperatures between T =5 K and T =70 K . The measurements reveal that the spin coherence (the transverse spin-relaxation time T2) of these centers is significantly shortened compared to low-E'-density SiO2 films and within error margins not dependent on temperature. In contrast, the spin-flip times (the longitudinal relaxation times T1) are dependent on the temperature but with much weaker dependence than low-density SiO2 , with the greatest deviations from low-density SiO2 seen for T =5 K . These results, discussed in the context of the spin-relaxation dynamics of dangling-bond states of other silicon-based disordered solids, indicate the suitability of E' centers in high-density SiO2 as probe spins for SSTFM.

  12. 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.

  13. Electrical properties of pseudo-single-crystalline germanium thin-film-transistors fabricated on glass substrates

    NASA Astrophysics Data System (ADS)

    Kasahara, K.; Nagatomi, Y.; Yamamoto, K.; Higashi, H.; Nakano, M.; Yamada, S.; Wang, D.; Nakashima, H.; Hamaya, K.

    2015-10-01

    By developing a low-temperature (≤300 °C) fabrication process for the gate-stack structure on Ge(111), we study electrical properties of thin film transistors (TFTs) consisting of (111)-oriented pseudo-single-crystalline-germanium (PSC-Ge) channels on glass. Although the Hall mobility ( μ Hall ) of p-type PSC-Ge layers reaches 210 cm2/V s and the gate-stack/Ge interface has low trap density, we observe field-effect-mobility (μFE) fluctuation in the p-channel TFTs from 8.2 to 71 cm2/V s, depending on the thickness of the PSC-Ge layer. Considering the μFE fluctuation and low I on / I off ratio in the p-TFTs, we infer the presence of defective Ge layers near the surface of the glass substrate. This study reveals that it is quite important for the high-performance p-Ge TFTs to improve the quality of the Ge layer near the surface of the glass substrate or to choose other materials with better Ge/substrate interface qualities.

  14. 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.

  15. 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}.

  16. 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

  17. 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)

  18. 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)

  19. 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…

  20. 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.

  1. NH3 molecular doping of silicon nanowires grown along the [112], [110], [001], and [111] orientations

    PubMed Central

    2012-01-01

    The possibility that an adsorbed molecule could provide shallow electronic states that could be thermally excited has received less attention than substitutional impurities and could potentially have a high impact in the doping of silicon nanowires (SiNWs). We show that molecular-based ex-situ doping, where NH3 is adsorbed at the sidewall of the SiNW, can be an alternative path to n-type doping. By means of first-principle electronic structure calculations, we show that NH3 is a shallow donor regardless of the growth orientation of the SiNWs. Also, we discuss quantum confinement and its relation with the depth of the NH3 doping state, showing that the widening of the bandgap makes the molecular donor level deeper, thus more difficult to activate. PMID:22709657

  2. Direct observation of single domains in poled (111) PZT (PbZr 0.25Ti 0.75O 3) films

    NASA Astrophysics Data System (ADS)

    Zybill, C. E.; Boubekeur, H.; Radojkovic, P.; Schwartzkopff, M.; Hartmann, E.; Koch, F.; Groos, G.; Rezek, B.; Bruchhaus, R.; Wersing, W.

    1999-10-01

    Films of (111) oriented poled ferroelectric lead zirconate titanate (PZT) crystallites on (100)Si/SiO 2/(111) Pt were investigated by scanning tunneling microscopy (STM), atomic force microscopy (AFM) and small angle X-ray scattering (SAXS). SAXS investigations allowed to estimate a mean value of domain thickness of 17.5 nm. Exertion of stress (5.1×10 4 N m -2) to the film resulted in an increase of domain width of ˜1%. After metallization of the PZT surface with a Cr-Ni film of 5.2 nm or a Ti film of 5.0 nm thickness, domains were visible by STM measurements as parallel stripes on the surface with a width of 15-20 nm. A downward vertical corrugation of 1.0-1.5 nm typically occurred at the intersection site of domain walls with the surface. Its presence is ascribed to shear strain originating from coherency defects in the interface. High resolution AFM with electron beam deposited supertips on unmetallized samples revealed areas of typically several micrometers in diameter showing crystallites with perfectly aligned domains of 10-15 nm width. The domains formed parallel slabs of twinned-crystallites with their polarization c-axis changing alternately from [001] to [010] direction. For a fully poled (111) PZT film, the c-axis of each (90°) domain is inclined towards the surface by 35° and tilted against the surface normal by +45 or -45°, respectively. These results generally confirm the Speck-Streiffer-Pompe-Romanov domain model which predicts for a (111) PZT film of 500 nm thickness a polyvariant with alternating (90°) domains of 16.4 nm width.

  3. Effect of Growth Temperature on the Magnetic, Microwave, and Cation Inversion Properties on NiFe2O4 Thin Films Deposited by Pulsed Laser Ablation Deposition

    SciTech Connect

    Chinnasamy,C.; Yoon, S.; Yang, A.; Baraskar, A.; Vittoria, C.; Harris, V.

    2007-01-01

    First principles band structure calculations suggest that the preferential occupation of Ni{sup 2+} ions on the tetrahedral sites in NiFe{sub 2}O{sub 4} would lead to an enhancement of the exchange integral and subsequently the Neel temperature and magnetization. To this end, we have deposited NiFe{sub 2}O{sub 4} films on MgO substrates by pulsed laser deposition. The substrate temperature was varied from 700 to 900 {sup o}C at 5 mTorr of O2 pressure. The films were annealed at 1000 {sup o}C for different times prior to their characterization. X-ray diffraction spectra showed either (100) or (111) orientation with the spinel structure dependent on the substrate orientation. Magnetic studies showed a magnetization value of 2.7 kG at 300 K. The magnetic moment was increased to the bulk value as a result of postdeposition annealing at 1000 {sup o}C. The as produced films show that the ferromagnetic resonance linewidth at 9.61 GHz was 1.5 kOe, and it was reduced to 0.34 kOe after postannealing at 1000 {sup o}C. This suggests that the annealing led to the redistribution of Ni{sup 2+} ions to their equilibrium octahedral sites. Further, it is shown that the magnetically preferred direction of H{sub a} can be aligned perpendicular to the film plane when films are grown with a fixed oxygen pressure of 5 mTorr for films deposited at 700 and 900 {sup o}C.

  4. Magnetostriction in epitaxial SrTi(1-x)Fe(x)O(3-δ) perovskite films with x = 0.13 and 0.35.

    PubMed

    Kim, Dong Hun; Aimon, Nicolas M; Bi, Lei; Florez, J M; Dionne, Gerald F; Ross, C A

    2013-01-16

    The crystal structure, magnetic anisotropy and magnetoelasticity of epitaxial SrTi(0.87)Fe(0.13)O(3-δ) (STF13) and SrTi(0.65)Fe(0.35)O(3-δ) (STF35) films grown on (001), (011), and (111) oriented SrTiO(3) substrates were investigated. The films grew with compressive in-plane strain and underwent tetragonal, monoclinic, and rhombohedral distortions on the (001), (011), and (111) substrates, respectively. All samples showed room temperature magnetic hysteresis loops with strong out-of-plane anisotropy. The resulting magnetoelastic anisotropy was an order of magnitude greater than the magnetocrystalline and shape anisotropies. Magnetoelastic coefficients of B(1) =- 6.7 × 10(6) and B(2) =- 28 to -26 × 10(6) erg cm(-3) for STF13 and B(1) =- 2.0 × 10(6) and B(2) =- 5.4 to -3.9 × 10(6) erg cm(-3) for STF35 were determined from the magnetic anisotropy and lattice strain, corresponding to magnetostriction constants of λ(100) = 2.09 × 10(-6) and λ(111) = 7.68 × 10(-6) for STF13, and λ(100) = 0.62 × 10(-6) and λ(111) = 1.07 × 10(-6) for STF35.

  5. 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)

  6. 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.

  7. 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)

  8. 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)

  9. 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.

  10. 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…

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. 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.

  16. 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.

  17. 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)

  18. Sputter Deposition of Yttrium-Barium Superconductor and Strontium Titanium Oxide Barrier Layer Thin Films

    NASA Astrophysics Data System (ADS)

    Truman, James Kelly

    1992-01-01

    The commercial application of superconducting rm YBa_2Cu_3O_{7 -x} thin films requires the development of deposition methods which can be used to reproducibly deposit films with good superconducting properties on insulating and semiconducting substrates. Sputter deposition is the most popular method to fabricate Y-Ba-Cu-O superconductor thin films, but when used in the standard configuration suffers from a deviation between the compositions of the Y-Ba-Cu-O sputter target and deposited films, which is thought to be primarily due to resputtering of the film by negative ions sputtered from the target. In this study, the negative ions were explicitly identified and were found to consist predominantly O^-. The sputter yield of O^- was found to depend on the Ba compound used in the fabrication of Y -Ba-Cu-O targets and was related to the electronegativity difference between the components. An unreacted mixture of rm Y_2O_3, CuO, and BaF_2 was found to have the lowest O^- yield among targets with Y:Ba:Cu = 1:2:3. The high yield of O^- from rm YBa_2Cu_3O _{7-x} was found to depend on the target temperature and be due to the excess oxygen present. The SIMS negative ion data supported the composition data for sputter-deposited Y-Ba-Cu-O films. Targets using BaF _2 were found to improve the Ba deficiency, the run-to-run irreproducibility and the nonuniformity of the film composition typically found in sputtered Y -Ba-Cu-O films. Superconducting Y-Ba-Cu-O films were formed on SrTiO_3 substrates by post-deposition heat treatment of Y-Ba-Cu-O-F films in humid oxygen. The growth of superconducting rm YBa_2Cu_3O_{7-x}, thin films on common substrates such as sapphire or silicon requires the use of a barrier layer to prevent the deleterious interaction which occurs between Y-Ba-Cu-O films and these substrates. Barrier layers of SrTiO_3 were studied and found to exhibit textured growth with a preferred (111) orientation on (100) Si substrates. However, SrTiO_3 was found to be

  19. Thin film growth of a topological crystal insulator SnTe on the CdTe (111) surface by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Ishikawa, Ryo; Yamaguchi, Tomonari; Ohtaki, Yusuke; Akiyama, Ryota; Kuroda, Shinji

    2016-11-01

    We report molecular beam epitaxial growth of a SnTe (111) layer on a CdTe template, fabricated by depositing it on a GaAs (111)A substrate, instead of BaF2 which has been conventionally used as a substrate. By optimizing temperatures for the growth of both SnTe and CdTe layers and the SnTe growth rate, we could obtain SnTe layers of the single phase grown only in the (111) orientation and of much improved surface morphology from the viewpoint of the extension and the flatness of flat regions, compared to the layers grown on BaF2. In this optimal growth condition, we have also achieved a low hole density of the order of 1017 cm-3 at 4 K, the lowest value ever reported for SnTe thin films without additional doping. In the magnetoresistance measurement on this optimized SnTe layer, we observe characteristic negative magneto-conductance which is attributed to the weak antilocalization effect of the two-dimensional transport in the topological surface state.

  20. Science Fiction on Film.

    ERIC Educational Resources Information Center

    Burmester, David

    1985-01-01

    Reviews science fiction films used in a science fiction class. Discusses feature films, short science fiction films, short story adaptations, original science fiction pieces and factual science films that enrich literature. (EL)

  1. 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.

  2. 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…

  3. 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)

  4. War. Peace. Film Guide.

    ERIC Educational Resources Information Center

    Dougall, Lucy

    The revised and expanded film guide designed for educators includes annotations of over 200 films, plus a large number of program resources for intelligent film use. Selected from over five hundred films previewed from 1969, up-to-date films were chosen that would help interpret the causes of war, increase awareness of the dehumanizing effects of…

  5. Pulsed-laser deposition and characterization of hetero-paired thin-film gallium arsenide

    NASA Astrophysics Data System (ADS)

    Erlacher, Artur

    2005-07-01

    The III-V compound semiconductor gallium arsenide (GaAs) possesses a direct bandgap and a six-fold higher electron mobility than the indirect semiconductor silicon (Si). For that reason GaAs based devices are of particular significance for high-speed digital (mobile phones, radar systems, all-optical switches, etc.) and high-performance optoelectronic applications (high-efficiency solar cells, high-power IR laser diodes, etc.). The state-of-the-art GaAs device production is mainly covered by rather sophisticated and expensive techniques such as molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD). This project investigated pulsed-laser deposition (PLD) as a cost effective alternative method to grow thin-film GaAs. In addition, detailed data of electronic and optoelectronic properties of GaAs/Si hetero-structures were obtained. During this dissertation about 110 GaAs thin films have been formed on glass and Si substrates by PLD with different process parameters. The crystal structure and surface properties of the thin films have been analyzed by x-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. Electronic and optoelectronic features of GaAs/Si hetero-structures have been investigated by current-voltage (I-V) characterization and photocurrent (PC) experiments. In addition, theoretical models describing the ablation temperature and the deposited film profile are presented. The experimental results reveal that the sample textures consist of a predominate amorphous portion and (111) oriented crystallites. Furthermore, these features are widely independent of the laser ablation wavelength and do not depend on the substrate surface texture. However, the ablation wavelength influences and varies the formation of clusters on the film surfaces as demonstrated with AFM. Doped GaAs thin films deposited on counter-doped Si substrates exhibit rectifying I-V characteristics. The spectral response data shows that the Ga

  6. Effect of postdeposition annealing on the electrical properties of β-Ga{sub 2}O{sub 3} thin films grown on p-Si by plasma-enhanced atomic layer deposition

    SciTech Connect

    Altuntas, Halit; Donmez, Inci; Ozgit-Akgun, Cagla; Biyikli, Necmi

    2014-07-01

    Ga{sub 2}O{sub 3} dielectric thin films were deposited on (111)-oriented p-type silicon wafers by plasma-enhanced atomic layer deposition using trimethylgallium and oxygen plasma. Structural analysis of the Ga{sub 2}O{sub 3} thin films was carried out using grazing-incidence x-ray diffraction. As-deposited films were amorphous. Upon postdeposition annealing at 700, 800, and 900 °C for 30 min under N{sub 2} ambient, films crystallized into β-form monoclinic structure. Electrical properties of the β-Ga{sub 2}O{sub 3} thin films were then investigated by fabricating and characterizing Al/β-Ga{sub 2}O{sub 3}/p-Si metal–oxide-semiconductor capacitors. The effect of postdeposition annealing on the leakage current densities, leakage current conduction mechanisms, dielectric constants, flat-band voltages, reverse breakdown voltages, threshold voltages, and effective oxide charges of the capacitors were presented. The effective oxide charges (Q{sub eff}) were calculated from the capacitance–voltage (C-V) curves using the flat-band voltage shift and were found as 2.6 × 10{sup 12}, 1.9 × 10{sup 12}, and 2.5 × 10{sup 12} cm{sup −2} for samples annealed at 700, 800, and 900 °C, respectively. Effective dielectric constants of the films decreased with increasing annealing temperature. This situation was attributed to the formation of an interfacial SiO{sub 2} layer during annealing process. Leakage mechanisms in the regions where current increases gradually with voltage were well fitted by the Schottky emission model for films annealed at 700 and 900 °C, and by the Frenkel–Poole emission model for film annealed at 800 °C. Leakage current density was found to improve with annealing temperature. β-Ga{sub 2}O{sub 3} thin film annealed at 800 °C exhibited the highest reverse breakdown field value.

  7. Filming The Man Hunters

    ERIC Educational Resources Information Center

    Hockings, Paul

    1976-01-01

    "The Man Hunters" is a film about paleoanthropology. This article is a personal account of how the film was put together using anthropological knowledge and numerous anthropologists and how the film was received by the American public. (Author)

  8. 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.

  9. Processing and properties of lead zirconate titanate thin films on gallium nitride and ruthenium by sol-gel and chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Cao, Wei

    The Pb(ZrxTi1-x)O3 (PZT) thin films are potential candidates for ferroelectric random access memory (FeRAM) devices and components for microelectromechanical systems (MEMS). For example, the PZT/GaN system is being explored as RF MEMS devices for insertion in RF communication systems. A reproducible sol-gel process was developed for the deposition of PZT films on wurtzite (0001) GaN/sapphire substrates. The composition, crystallography, and interfacial nanochemistry were evaluated by various characterization techniques. The PZT/GaN heterostructure exhibited a chemically sharp interface with insignificant interdiffusion between PZT and GaN layers. However, PZT in metal -ferroelectric -semiconductor (MFS) configuration showed lower capacitance and asymmetrical polarization hysteresis compared to PZT in metal-ferroelectric-metal configuration. Such a deviation was attributed to the high depolarization field (Edepol) within PZT. To mitigate this issue, a two-pronged approach was used. First, the calculated spatial distribution of the electric field and potential, which stem from all the charge densities within the MFS configuration, demonstrated that by adjusting controllable parameters, one can minimize Edepol and maximize polarization. Second, a robust metal-organic chemical vapor deposition (MOCVD) process was developed to fabricate high quality PZT thin films on GaN. In this experimental approach, phase-pure and highly (111) oriented PZT films were deposited on GaN/sapphire substrates by MOCVD. The orientation relationships of PZT/GaN system were determined using x-ray pole figure and high-resolution transmission electron microscopy (TEM). The nanochemistry of the PZT/GaN interface, studied using analytical TEM, indicated a chemically sharp interface with interdiffusion limited to a region below 5 nm. The properties of MOCVD-PZT on GaN are briefly compared with PZT by sol-gel processing, rf sputtering, and pulsed laser deposition. Additionally, a preliminary study

  10. 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

  11. 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.

  12. Film Presentation Techniques.

    ERIC Educational Resources Information Center

    Monod, Pierre

    1976-01-01

    This article discusses three types of films and their use in the second language classroom. The description film is objective and static, and elicits adjectives and adverbs. This kind of film should be presented three times, each time followed by a different set of learning exercises. The culture film - characterized by descriptions, scenes from…

  13. Films on Oceanography.

    ERIC Educational Resources Information Center

    Cuzon du Rest, R. P.

    This film list compiled by the U.S. Naval Oceanographic Office is separated into six categories: general oceanography, biology, chemistry, engineering, geology, and physics. An index of films is followed by addresses of Naval Districts and lists of distribution centers. Each film listed is described as to content, running time, type of film,…

  14. Thin film interference of colloidal thin films.

    PubMed

    Cong, Hailin; Cao, Weixiao

    2004-09-14

    A stairlike colloidal crystal thin film composed of poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) monodispersed colloids was fabricated on an inclined silicon substrate. Different bright colors were observed on the various parts of the film with different layers as white light irradiated perpendicularly on it. The relationship between the colors and layers of the film was investigated and discussed according to the principle of thin film interference. On the basis of the phenomenon of thin film interference, a one-layer colloidal film having uniform color was researched and it would display diverse colors before and after swollen by styrene (St). A circular stairlike colloidal film was achieved to mimic the colors of the peacock tail feather.

  15. 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.

  16. Endotaxial growth of CoSi2 within (111) oriented Si in a molecular beam epitaxy system

    NASA Technical Reports Server (NTRS)

    George, T.; Fathauer, R. W.

    1991-01-01

    A new mode of growth is reported in which buried metallic layers can be fabricated within a single-crystal semiconductor through preferential subsurface growth on previously-grown 'seed' regions. The deposition of Co at 800 C at a rate of 0.01 nm/s on (111) Si substrates containing buried CoSi2 columns 40-100 nm below the Si surface results in the growth and coalescence of these subsurface columns. The formation of a CoSi2 layer on the Si surface is suppressed by this growth mode. It is proposed that the high diffusion rate of Co at 800 C, coupled with the high growth rate of CoSi2 at the subsurface columns, is responsible for this preferred 'endotaxial' growth mode. This growth technique was used to produce a continuous buried single-crystal layer of CoSi2 under a single-crystal Si capping layer.

  17. Durable solar mirror films

    DOEpatents

    O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.; Katare, Rajesh K.; Jing, Naiyong; North, Diane; Peterson, Eric M.

    2017-02-14

    The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

  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. The Educational Film Industry

    ERIC Educational Resources Information Center

    Tortora, Vincent R.; Schillaci, Peter

    1975-01-01

    Increased dialog is needed among educational film producers, distributors, and consumers in order to be sure that what is being produced meets educators' needs and also to help solve the financial problems of the film industry. (LS)

  20. Microstructure of Thin Films

    DTIC Science & Technology

    1990-02-07

    optical properties ." (Final text in preparation). John Lehan, "Microstructural analysis of thin films by Rutherford Backscattering...correlation of optical properties and micro- Ion assisted deposition (IAD) is known to produce structure of IAD thin films with ion beam parameters thin films ...1.5-eV interband absorption. P (eV) R (%) P (, -V) R %) Optical properties of metal thin films in the spectral 0 98.3 0 88.8 range of

  1. 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…

  2. 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…

  3. Australian Film Studies.

    ERIC Educational Resources Information Center

    Breen, Myles P.

    Although Australia had a vigorous film industry in the silent film era, it was stifled in the 1930s when United States and British interests bought up the Australian distribution channels and closed down the indigenous industry. However, the industry and film study have undergone a renaissance since the advent of the Labor government in 1972,…

  4. The Language of Film.

    ERIC Educational Resources Information Center

    Whitaker, Rod

    This book, designed for the film maker, critic, and serious filmgoer, explores elements of filmic expression from the creative and perceptual points of view. Chapters (1) trace the linguistic and mechanical development of film, (2) discuss the contributions of image and sound to film content, (3) suggest the contributions of editing and montage,…

  5. Playing With Film.

    ERIC Educational Resources Information Center

    Gaffney, Maureen, Ed.

    1980-01-01

    Designed for media specialists and educators, this issue includes five articles on innovative museum film programs. The first article describes a successful film program conducted at the Staten Island Children's Museum. The second article describes inventive children's programs at the Delaware Museum of Art. The programs use films and activities…

  6. 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…

  7. 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…

  8. 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…

  9. 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)

  10. 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…

  11. Film Program Notes from the Current Holdings of the Anthology Film Archives; Outlines of 41 Films.

    ERIC Educational Resources Information Center

    Anthology Film Archives, New York, NY.

    This collection of film program notes includes mixed commentary on some of the films held in the Anthology Film Archives (a film and book library in New York City). Some of the films are described by synopsis of the episodes and others by translation into English of the foreign language subtitles. However, each film noted is identified by full…

  12. Electrically Conductive Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, Anne K.; Ezzel, Stephen A.; Taylor, Larry T.; Boston, Harold G.

    1993-01-01

    Semiconducting surfaces of SnO2 formed by curing polyamic acids containing tin complexes. Polyimide films made semiconductive via incorporation of semiconductive surface layers of SnO2. If SnO2-surfaced polyimide film used as free-standing film, then semiconductive layer protected by top coat of polyimide, deposited as film from solution directly onto SnO2. Resultant films flexible and resistant to both weather and high temperature. Used on aircraft to provide resistance to lightning strikes, and in microelectronics and flexible circuitry.

  13. 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.

  14. 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.

  15. 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.

  16. Neutron Diffraction Investigations of Magnetism in BiFeO3 Epitaxial Films

    DTIC Science & Technology

    2011-01-01

    ordering temperatures are far too low for device applications. Perovskite -structured BiFeO 3 (BFO) with a rhom- bohedral distortion along the [111...adjacent planes, leading to the doubling of the mag- netic unit cell in all crystallographic directions from the nuclear unit cell. [ 22 ] This is

  17. "Silent" Films Revisited: Captioned Films for the Deaf.

    ERIC Educational Resources Information Center

    Kovalik, Gail L.

    1992-01-01

    Provides a history of the Captioned Films/Videos for the Deaf program and describes the kinds of films and videos available, including feature films and educational materials. Silent films are discussed; captioning processes are described; implications for librarians are discussed; and regional depository libraries for captioned films for the deaf…

  18. 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.

  19. 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…

  20. 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…

  1. 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…

  2. 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.

  3. Daylight Redirecting Window Film

    DTIC Science & Technology

    2013-12-01

    EW-201014) Daylight Redirecting Window Film December 2013 This document has been cleared for public release; Distribution...DEC 2013 2. REPORT TYPE 3. DATES COVERED 00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Daylight Redirecting Window Film 5a. CONTRACT NUMBER...CCE cost of conserved energy DoD Department of Defense DRF daylight redirecting film EPA U.S. Environmental Protection Agency ESTCP

  4. Thermally processed keratin films

    NASA Astrophysics Data System (ADS)

    Barone, Justin; Schmidt, Walter

    2004-03-01

    Keratin obtained from poultry feathers is blended with -OH containing second phases. Films are prepared by pressing the blended keratin at temperatures concurrent with typical polymer processing temperatures. The films are completely cohesive as opposed to partially cohesive if pressed under the same conditions without blending. The films are "tough" and the mechanical properties show similarities to the properties of commercially available commodity thermoplastics. The keratin films are produced in a few minutes without reducing or oxidizing agents. The mobility of the keratin chains during blending is shown to relate to the serine (S), threonine (T), and tyrosine (Y) contents in the amino acid sequence relative to cystine (C).

  5. 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.

  6. Film tension of liquid nano-film from molecular modeling

    NASA Astrophysics Data System (ADS)

    Peng, Tiefeng; Yang, Siyuan; Xiang, Fan; Liang, Yunpei; Li, Qibin; Gao, Xuechao; Liu, Sanjun

    2017-02-01

    Due to its geometry simplicity, the forces of thin liquid film are widely investigated and equivalently employed to explore the phys-chemical properties and mechanical stability of many other surfaces or colloid ensembles. The surface tension of bulk liquid (σ∞) and film tension (γ) are the most important parameters. Considering the insufficiency of detailed interpretation of film tension under micro-scale circumstances, a method for film tension was proposed based on numerical modeling. Assuming surface tension at different slab thicknesses being identical to the surface tension of film, the surface tension and disjoining pressure were subsequently used to evaluate the film tension based on the derivation of film thermodynamics, and a decreasing tendency was discovered for low temperature regions. The influence of saline concentration on nano-films was also investigated, and the comparison of film tensions suggested that higher concentration yielded larger film tension, with stronger decreasing intensity as a function of film thickness. Meanwhile, at thick film range (15-20 nm), film tension of higher concentration film continued to decrease as thickness increase, however it arrived to constant value for that of lower concentration. Finally, it was found that the film tension was almost independent on the film curvature, but varied with the thickness. The approach is applicable to symmetric emulsion films containing surfactants and bi-layer lipid films.

  7. 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)

  8. Optical thin film devices

    NASA Astrophysics Data System (ADS)

    Mao, Shuzheng

    1991-11-01

    Thin film devices are applied to almost all modern scientific instruments, and these devices, especially optical thin film devices, play an essential role in the performances of the instruments, therefore, they are attracting more and more attention. Now there are numerous kinds of thin film devices and their applications are very diversified. The 300-page book, 'Thin Film Device and Applications,' by Prof. K. L. Chopra gives some general ideas, and my paper also outlines the designs, fabrication, and applications of some optical thin film devices made in my laboratory. Optical thin film devices have been greatly developed in the recent decades. Prof. A. Thelan has given a number of papers on the theory and techniques, Prof. H. A. Macleod's book, 'Thin Film Optical Filters,' has concisely concluded the important concepts of optical thin film devices, and Prof. J. A. Dobrowobski has proposed many successful designs for optical thin film devices. Recently, fully-automatic plants make it easier to produce thin film devices with various spectrum requirements, and some companies, such as Balzers, Leybold AG, Satis Vacuum AG, etc., have manufactured such kinds of coating plants for research or mass-production, and the successful example is the production of multilayer antireflection coatings with high stability and reproducibility. Therefore, it could be said that the design of optical thin film devices and coating plants is quite mature. However, we cannot expect that every problem has been solved, the R&D work still continues, the competition still continues, and new design concepts, new techniques, and new film materials are continually developed. Meanwhile, the high-price of fully-automatic coating plants makes unpopular, and automatic design of coating stacks is only the technique for optimizing the manual design according to the physical concepts and experience, in addition, not only the optical system, but also working environment should be taken into account when

  9. 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)

  10. 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.

  11. 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.

  12. 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…

  13. 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…

  14. 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…

  15. Films for Childhood Educators.

    ERIC Educational Resources Information Center

    Winick, Mariann Pezzella

    This is a review of films in six thematic groupings: (1) The Open Classroom on Film, (2) The Developing Child, (3) Readiness and the Natural Abilities of Children, (4) Schools as Mirrors, (5) Families: Weavers of Civilization, (6) Children: The Legacy. Each review describes strengths and weaknesses, and gives guidance for follow-up usage. All…

  16. 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…

  17. 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…

  18. 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.

  19. 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…

  20. 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.

  1. 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.

  2. 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,…

  3. Radiographic film package

    SciTech Connect

    Muylle, W. E.

    1985-08-27

    A radiographic film package for non-destructive testing, comprising a radiographic film sheet, an intensifying screen with a layer of lead bonded to a paper foil, and a vacuum heat-sealed wrapper with a layer of aluminum and a heat-sealed easy-peelable thermoplastic layer.

  4. 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…

  5. 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…

  6. 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.

  7. 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.

  8. Mechanics of Thin Films

    DTIC Science & Technology

    1992-02-06

    S. Hwang, Thermal conductivity of thin films: measurement and microstructural effects, in Thin- film heat transfer, properties and processing, ed...thermal, electrical, optical and magnetic properties . As typical examples we mention microelectronics, optical coatings and multilayers for use in optical...interplay between mechanical properties (elastic moduli), thermal properties (thermal conductivity, thermal expansion coefficient), and optical

  9. 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…

  10. 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…

  11. 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

  12. 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.

  13. 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…

  14. Film Theory and Hugo Munsterberg's "The Film": A Psychological Study.

    ERIC Educational Resources Information Center

    Wicclair, Mark R.

    1978-01-01

    Hugo Munsterberg's "The Film: A Psychological Study" is one of the earliest essays in the area of film theory. Unfortunately, it has remained relatively unknown since its publication in 1916. The author discusses two concepts raised by Munsterberg: the contrast between films in the theatrical mode and films in the cinematic mode.…

  15. 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.

  16. 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.

  17. Feature Films in Your Library

    ERIC Educational Resources Information Center

    Spehr, Paul

    1970-01-01

    Trained film librarians, given a well planned and carefully developed program can answer the needs of the new film students. Includes lists of motion picture distributors, cinema periodicals, significant feature films, and classic American feature-length films. (Author/JB)

  18. Film Images of Private Schools.

    ERIC Educational Resources Information Center

    Resnick, David

    2000-01-01

    Examines public debate over private education in the context of the Hollywood dramatic feature film. Analyses four recent films that all portray private schools negatively. Film representation of public schools is more optimistic. Asserts that the films ignore or misrepresent three strengths of private education: effective leadership, small school…

  19. Reference for radiographic film interpreters

    NASA Technical Reports Server (NTRS)

    Austin, D. L.

    1970-01-01

    Reference of X-ray film images provides examples of weld defects, film quality, stainless steel welded tubing, and acceptable weld conditions. A summary sheet details the discrepancies shown on the film strip. This reference aids in interpreting and evaluating radiographic film of weldments.

  20. Film: The Reality of Being.

    ERIC Educational Resources Information Center

    Sheratsky, Rodney E.

    The visual media, particularly film, has challenged today's educators by competing for students' time and interests and by providing a relevancy that books designed for school use do not have. Using film study to combat the supposed immorality of theatrical films and employing instructional film to transmit information has provided a negative…

  1. 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…

  2. Children's Film Programming: A Handbook.

    ERIC Educational Resources Information Center

    Gallery Association of New York State, Inc.

    Directed at the staffs of art institutions, community centers, libraries, historical societies, and schools, this practical guide is intended to help in the selection and use of films for children. "Film," in this handbook refers to 16mm films presented in public screenings--not videotape versions of films, and not material originally…

  3. 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)

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Ion beam deposited protective films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.

    1981-01-01

    Single or dual ion beam sources were used to deposit thin films for different applications. Metal and metal oxide films were evaluated as protective coatings for the materials. Film adherence was measured and the most promising films were then tested under environments similar to operating conditions. It was shown that some materials do protect die material (H-13 steel) and do reduce thermal fatigue. Diamondlike films have many useful applications. A series of experiments were conducted to define and optimize new approaches to the manufacture of such films. A dual beam system using argon and methane gases was developed to generate these films.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. Nanostructured thermoplastic polyimide films

    DOEpatents

    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.

  16. Multifunctional thin film surface

    DOEpatents

    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.

  17. Oxide Films RF Applications

    DTIC Science & Technology

    2006-06-01

    different stabilities and properties . Certain applications, such as integrated dielectrics or photoelectrochemical cells, require thin films of TiO2 that...interesting dielectric properties . Another is that the (001) plane of anatase TiO2 is one of the two main layers stacked along the (100) direction in...Public Release 13. SUPPLEMENTARY NOTES .bDib ibuUl I U 1 iited 14. ABSTRACT TiO2 films were grown using a reactive molecular beam epitaxy system

  18. 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.

  19. Magnetoresistance of Au films

    DOE PAGES

    Zhang, D. L.; Song, X. H.; Zhang, X.; ...

    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.

  20. Dielectric Composite Thin Films

    DTIC Science & Technology

    1989-11-01

    more compressive under deposition conditions, such as high temperature, low pressure or energetic ion bombardment, that produce a more densely packed...film porosity and silica content. Thus, films formed at high temperatures and low pressures , as well as under ion bombardment during deposition, have...and their mixtures were deposited on 100-300 *C substrates and under reactive gas III. RESULTS pressures of 1-10x 10- Torr 02. 02 was UHP grade with A

  1. 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.

  2. Multiresonant layered plasmonic films

    SciTech Connect

    DeVetter, Brent M.; Bernacki, Bruce E.; Bennett, Wendy D.; Schemer-Kohrn, Alan; Alvine, Kyle J.

    2017-01-01

    Multi-resonant nanoplasmonic films have numerous applications in areas such as nonlinear optics, sensing, and tamper indication. While techniques such as focused ion beam milling and electron beam lithography can produce high-quality multi-resonant films, these techniques are expensive, serial processes that are difficult to scale at the manufacturing level. Here, we present the fabrication of multi-resonant nanoplasmonic films using a layered stacking technique. Periodically-spaced gold nanocup substrates were fabricated using self-assembled polystyrene nanospheres followed by oxygen plasma etching and metal deposition via magnetron sputter coating. By adjusting etch parameters and initial nanosphere size, it was possible to achieve an optical response ranging from the visible to the near-infrared. Singly resonant, flexible films were first made by performing peel-off using an adhesive-coated polyolefin film. Through stacking layers of the nanofilm, we demonstrate fabrication of multi-resonant films at a fraction of the cost and effort as compared to top-down lithographic techniques.

  3. Preparation of a heteroepitaxial La{sub x}Sr{sub y}Mn{sub z}O{sub 3}/BiFeO{sub 3} bilayer by r.f. magnetron sputtering with various oxygen gas flow ratios

    SciTech Connect

    Naganuma, H. Ichinose, T.; Begum, H. A.; Sato, S.; Oogane, M.; Ando, Y.; Han, X. F.; Miyazaki, T.; Bae, In-T.

    2014-08-15

    BiFeO{sub 3} (BFO) and La{sub x}Sr{sub y}Mn{sub z}O{sub 3} (LSMO) films were epitaxially grown on SrTiO{sub 3} (100) substrates by r.f. magnetron sputtering with various oxygen gas flow ratios (F{sub O2}). Compositional ratios of each atom in both of BFO and LSMO could be controlled kept to around 10 at.% by changing F{sub O2}. Adjusting the compositional ratio to La{sub 0.35}Sr{sub 0.15}Mn{sub 0.5}O{sub 3} not only increase T{sub c} 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 SrTiO{sub 3} 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.

  4. Tunable electronic and magnetism of SrTiO{sub 3}/BiFeO{sub 3} (001) superlattice: For electrochemical applications

    SciTech Connect

    Xu, Qiang; Sopiha, Kostiantyn; Sobhan, Mushtaq; Anariba, Franklin; Wu, Ping; Ong, Khuong Phuong; Zheng, Jian Wei

    2016-01-04

    Practical strategy in tuning the conductivity and magnetism of SrTiO{sub 3}/BiFeO{sub 3} (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 TiO{sub 2}/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.

  5. 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.

  6. Capacitor film surface assessment studies

    NASA Astrophysics Data System (ADS)

    Galperin, I.; White, W.

    1985-02-01

    In the present investigation of the optical surface of the three widely used, biaxially oriented capacitor films, polypropylene, polyvinylidene fluoride, and polyester, with attention to film surface defects and thickness variation, the defects and their rate of occurrence proved traceable in terms of polymer structure, chemical grouping, and fabrication processing. Film thickness variation was small, yet differed for each film type. Film breakdown voltages have been determined, and alternative causes for the voltage values obtained are proposed. A reciprocal relation is noted between the film breakdown voltage and the dielectric constant.

  7. 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.

  8. Dewetting of Thin Polymer Films

    NASA Astrophysics Data System (ADS)

    Dixit, P. S.; Sorensen, J. L.; Kent, M.; Jeon, H. S.

    2001-03-01

    DEWETTING OF THIN POLYMER FILMS P. S. Dixit,(1) J. L. Sorensen,(2) M. Kent,(2) H. S. Jeon*(1) (1) Department of Petroleum and Chemical Engineering, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, jeon@nmt.edu (2) Department 1832, Sandia National Laboratories, Albuquerque, NM. Dewetting of thin polymer films is of technological importance for a variety of applications such as protective coatings, dielectric layers, and adhesives. Stable and smooth films are required for the above applications. Above the glass transition temperature (Tg) the instability of polymer thin films on a nonwettable substrate can be occurred. The dewetting mechanism and structure of polypropylene (Tg = -20 ^circC) and polystyrene (Tg = 100 ^circC) thin films is investigated as a function of film thickness (25 Åh < 250 Åand quenching temperature. Contact angle measurements are used in conjunction with optical microscope to check the surface homogeneity of the films. Uniform thin films are prepared by spin casting the polymer solutions onto silicon substrates with different contact angles. We found that the stable and unstable regions of the thin films as a function of the film thickness and quenching temperature, and then constructed a stability diagram for the dewetting of thin polymer films. We also found that the dewetting patterns of the thin films are affected substantially by the changes of film thickness and quenching temperature.

  9. Virus-PEDOT Biocomposite Films

    PubMed Central

    Donavan, Keith C.; Arter, Jessica A.

    2012-01-01

    Virus-poly(3,4-ethylenedioxythiophene) (virus-PEDOT) biocomposite films are prepared by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) in aqueous electrolytes containing 12 mM LiClO4 and the bacteriophage M13. The concentration of virus in these solutions, [virus]soln, is varied from 3 nM to 15 nM. A quartz crystal microbalance is used to directly measure the total mass of the biocomposite film during its electrodeposition. In combination with a measurement of the electrodeposition charge, the mass of the virus incorporated into the film is calculated. These data show that concentration of the M13 within the electropolymerized film, [virus]film, increases linearly with [virus]soln. The incorporation of virus particles into the PEDOT film from solution is efficient, resulting in a concentration ratio: [virus]film:[virus]soln ≈450. Virus incorporation into the PEDOT causes roughening of the film topography that is observed using scanning electron microscopy and atomic force microscopy (AFM). The electrical conductivity of the virus-PEDOT film, measured perpendicular to the plane of the film using conductive tip AFM, decreases linearly with virus loading, from 270 μS/cm for pure PE-DOT films to 50 μS/cm for films containing 100 μM virus. The presence on the virus surface of displayed affinity peptides did not significantly influence the efficiency of incorporation into virus-PEDOT biocomposite films. PMID:22856875

  10. Filming eugenics: teaching the history of eugenics through film.

    PubMed

    Ooten, Melissa; Trembanis, Sarah

    2007-01-01

    In teaching eugenics to undergraduate students and general public audiences, film should he considered as a provocative and fruitful medium that can generate important discussions about the intersections among eugenics, gender, class, race, and sexuality. This paper considers the use of two films, A Bill of Divorcement and The Lynchburg Story, as pedagogical tools for the history of eugenics. The authors provide background information on the films and suggestions for using the films to foster an active engagement with the historical eugenics movement.

  11. 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.

  12. Holographic thin film analyzer

    NASA Technical Reports Server (NTRS)

    Williams, J. R.; Norden, B. N. (Inventor)

    1973-01-01

    A system for the analysis and measurement of thin films in which the light output of a laser is split into two beams is discribed. The first beam is focused to illuminate the entire area of a photographic plate and the second beam is colummated and directed through a relatively small portion of the photographic plate onto the sample with the film to be observed. The surface of the sample is positioned at a slight angle with respect to a plane normal to the second beam and the light reflected from the sample arrives back at the photographic plate in a region other than through which the second beam originally passes. By making two successive exposures during the deposition of material on the surface of the sample, holograms are recorded on the photographic plate. The plate is then developed and interference lines of the hologram provide a measurement of the film or material deposited between exposure.

  13. Thin θ -film optics

    NASA Astrophysics Data System (ADS)

    Huerta, Luis

    2016-12-01

    A Chern-Simons theory in 3D is accomplished by the so-called θ term in the action (θ /2 )∫F ∧F , which contributes only to observable effects on the boundaries of such a system. When electromagnetic radiation interacts with the system, the wave is reflected and its polarization is rotated at the interface, even when both the θ system and the environment are pure vacuum. These topics have been studied extensively. Here, we investigate the optical properties of a thin θ film, where multiple internal reflections could interfere coherently. The cases of pure vacuum and a material with magnetoelectric properties are analyzed. It is found that the film reflectance is enhanced compared to ordinary non-θ systems and the interplay between magnetoelectric properties and the θ parameter yield film opacity and polarization properties which could be interesting in the case of topological insulators, among other topological systems.

  14. 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.

  15. 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.

  16. 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)

  17. 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.

  18. 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.

  19. 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";…

  20. Biomimetic thin film deposition

    NASA Astrophysics Data System (ADS)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  1. Superconducting Electronic Film Structures

    DTIC Science & Technology

    1991-02-14

    superconductors, yttrium , barium, copper, oxides, high, critical, temperature, thin films, tunneling, barriers, thallium, sputtering. 19. ABSTRACT (Continue on...50*C lower than that required for YBCO. In common with YBCO, the best films grew epitaxially with a c-axis orientation on SrTiO3 , LaAIO 3, and NdGaO 3...for c-axis growth were (001) faces of LaAIO 3, NdGaO 3 , SrTiO3 , MgO. yttria-stabilized ZrO2 (YSZ), 11 and (1102) sapphire. Low substrate

  2. 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.

  3. 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.

  4. Thin Film Phosphor Development

    DTIC Science & Technology

    1989-01-01

    followed in Fig. 1. Two different garnet phases are observed in the fired films. The "low temperature " phase observed in the film treated at 9(X)°C has a... garnets ,1 121 thle experimentall~v-ob,•crved lattice constar.als correspond to the followving lmh composition for the low and high temperature phases...deposited, which is probably an yttrium rich garnet (see Figure 1). At I100)°C we start to see the appearance of both phases. As the firing temperature

  5. 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.

  6. VACUUM DEPOSITION OF THIN FILMS,

    DTIC Science & Technology

    The book deals with methods of obtaining and processing thin films , methods of measuring the deposition rate and thickness of thin-film layers, and...the main fields of application of thin films . Vacuum requirements and the requirements for the composition of the residual medium in thermal...evaporation and cathode sputtering are given, and modern methods of producing and measuring vacuums and the equipment used in obtaining thin films are described. (Author)

  7. Center for Thin Film Studies

    DTIC Science & Technology

    1991-01-22

    techniques for reducing roughness were developed and tested . Substrate Preparation We deposited Si films by sputtering on a variety of substrates, and...deposition," Mod. Phys. Lett. B 3, 1039 (1989). 41 42 Nd: YAG LASER ABLATION OF BaTiO 3 THIN FILMS *URSULA J. GIBSON, **J.A. RUFFNER,***J.J. MCNALLY...thin films of barium titanate onto a variety of substrates, using picosecond and nanosecond pulsed Nd: YAG lasers. The films were deposited from a hot

  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. 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.

  10. Coated Aluminized Film Resists Corrosion

    NASA Technical Reports Server (NTRS)

    Rockoff, H. J.

    1982-01-01

    Commercially available corrosion-protection coating allows less costly metals - aluminum in particular used in heat-reflecting films for thermal barriers. Previously, such films had to incorporate gold as reflective layer to withstand humidity, moisture, and salt spray without corroding. This protective coating prevents corrosion of metalized films during evironmental exposure yet remains flexible, thermally stable and clear.

  11. 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…

  12. Analysis of Film as Communication.

    ERIC Educational Resources Information Center

    Stupp, Vicki O'Donnell

    Films function as a persuasive process in that they bring about a reinforcement or change in attitude, belief, or behavior by producing a cognitive restructuring of the audience's frame of reference. Organized research into the effects of films falls into two categories: macro-media studies exploring the way films reflect the psychological…

  13. Polyheterocycle Langmuir-Blodgett Films

    DTIC Science & Technology

    1989-05-29

    3-alkyl thiophene) and Stearic acid LB films. Thc oricntation of single- and Multi-laycr films on platinum substrates have bccn studicd by Ncar Edgc...not surface active. The LB films were obtained by spreading a mixture of the poly(3-alkvl thiophenes) and stearic acid (C,71-5 COOH ) onto the water

  14. Making Diamondlike Films More Transparent

    NASA Technical Reports Server (NTRS)

    Mirtich, Michael J.; Kussmaul, Michael T.; Sovey, James S.; Banks, Bruce A.

    1994-01-01

    Diamondlike carbon films highly transparent to visible light made by dual-ion-beam deposition process. Hard, resistant to scratching, and hermetic. Used as protective coatings on eyeglasses, magnetic recording heads, computer hard disks, and windows in bar-code scanners. Amorphous diamondlike carbon films preferable to polycrystalline diamond films in these and other applications. Smooth and adherent and deposited at room temperature.

  15. 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.

  16. 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…

  17. 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)

  18. Surrealism and Film.

    ERIC Educational Resources Information Center

    Matthews, J. H.

    This book is a critical, genre study of surrealist films including a general discussion of the backgrounds, influences, and overall traits of surrealism as a mode of artistic response to an absurdist world. Citing the impetus of Jacques Vache and Andre Breton as the originators of surrealism, the work expands upon the themes of fractured realism…

  19. 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…

  20. Film as Composition.

    ERIC Educational Resources Information Center

    Costanzo, William

    1986-01-01

    Describes the development of a freshman English program based on the analogy of film as composition and discusses implications of this program for other teachers of writing at a time when television and movies are giving unprecedented competition to the printed page for students' attention. (HTH)

  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. Protein thin film machines.

    PubMed

    Federici, Stefania; Oliviero, Giulio; Hamad-Schifferli, Kimberly; Bergese, Paolo

    2010-12-01

    We report the first example of microcantilever beams that are reversibly driven by protein thin film machines fueled by cycling the salt concentration of the surrounding solution. We also show that upon the same salinity stimulus the drive can be completely reversed in its direction by introducing a surface coating ligand. Experimental results are throughout discussed within a general yet simple thermodynamic model.

  3. 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…

  4. 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…

  5. Balloon film strain measurement

    NASA Astrophysics Data System (ADS)

    Rand, James L.

    In order to understand the state of stress in scientific balloons, a need exists for the measurement of film deformation in flight. The results of a flight test program are reported where material strain was measured for the first time during the inflation, launch, ascent and float of a typical natural shape, zero pressure scientific balloon.

  6. 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…

  7. 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.

  8. 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.

  9. 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…

  10. 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…

  11. 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…

  12. Colorless, Transparent, Aromatic Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, A. K.; St. Clair, T. L.; Ezzell, K. S.; Ely, R. M.

    1986-01-01

    New process yields aromatic condensation polyimide films essentially colorless. Films between 90- and 100-percent transparent at visible wavelength of 500 nm. Optically transparent polyimide films made from variety of aromatic condensation polyimides. Range from very pale in color to colorless, compared to bright yellow color of conventional/ commercial aromatic polyimide film. Increased transparency achieved at no sacrifice in thermal stability, flexibility, toughness, or mechanical properties. These features extremely attractive as films or coating materials for aerospace applications or for any other applications where high optical transparency or thermal stability is required.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Lonsdaleite Films with Nanometer Thickness.

    PubMed

    Kvashnin, Alexander G; Sorokin, Pavel B

    2014-02-06

    We investigate the properties of potentially the stiffest quasi-2-D films with lonsdaleite structure. Using a combination of ab initio and empirical potential approaches, we analyze the elastic properties of lonsdaleite films in both elastic and inelastic regimes and compare them with graphene and diamond films. We review possible fabrication methods of lonsdaleite films using the pure nanoscale "bottom-up" paradigm: by connecting carbon layers in multilayered graphene. We propose the realization of this method in two ways: by applying direct pressure and by using the recently proposed chemically induced phase transition. For both cases, we construct the phase diagrams depending on temperature, pressure, and film thickness. Finally, we consider the electronic properties of lonsdaleite films and establish the nonlinear dependence of the band gap on the films' thicknesses and their lower effective masses in comparison with bulk crystal.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Magnetoresistance of Au films

    SciTech Connect

    Zhang, D. L. Song, X. H.; Zhang, X.; Zhang, X.-G.

    2014-12-14

    Classical magnetoresistance (MR) in nonmagnetic metals are conventionally understood in terms of the Kohler rule, with violation usually viewed as anomalous electron transport, in particular, as evidence of non-Fermi liquid behavior. Measurement of the 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 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. Consequently, the Kohler rule should not be used to distinguish normal and anomalous electron transport in solids.

  8. 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.

  9. Thin film composite electrolyte

    DOEpatents

    Schucker, Robert C.

    2007-08-14

    The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

  10. 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

  11. Waterborne Polymeric Films.

    DTIC Science & Technology

    1981-02-01

    Parameters of Test Fluids I " 3. Energies of Vaporization and Molar Volumes of Some Acrylic Monomers 29 4. Physical Properties of Synthetic Polymers 31 S...Physical Properties of Synthetic Acrylic Aqueous Dispersions 33 6. Anionic Acrylic Clear-film Formulations 35 7 Fluid Resistance of Anionic Acrylic...41 11. Energeis of Vaporization and Molar Volumes of Some Polyurethanes 45 12. Solution Properties of Synthetic Polyurethanes 47 13. Aqueous

  12. 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.

  13. Effect of Repetitive Film Showings on Learning.

    ERIC Educational Resources Information Center

    Mc Tavish, C. L.

    In a study made in 1949 to determine the increment in learning that could be attributed to repetition, four general science films were shown to each of four groups of college students in such a way that each group saw one of the films once, a second film twice, a third film three times, and a fourth film four times. The experimental population…

  14. 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…

  15. 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.

  16. Elasticity of Flowing Soap films

    NASA Astrophysics Data System (ADS)

    Kim, Ildoo; Mandre, Shreyas

    2016-11-01

    The robustness of soap films and bubbles manifests their mechanical stability. The single most important factor underlying the mechanical stability of soap films is its elasticity. Non-destructive measurement of the elasticity in these films has been cumbersome, because of its flowing nature. Here we provide a convenient, reproducible, and non-destructive method for measuring the elasticity by generating and inspecting Marangoni waves. Our method is based on generating an oblique shock by inserting a thin cylindrical obstacle in the flowing film, and converting the measured the shock angle to elasticity. Using this method, we find a constant value for the elasticity of 22 dyne/cm in the commonly used range of film widths, thicknesses or flow rates, implying that the surface of the film is chemically saturated with soap molecules.

  17. 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.

  18. Propagation of linear and nonlinear spin wave excitations in YIG and Lu2.04Bi0.96Fe5O12 films studied by space resolved Brillouin light scattering (abstract)

    NASA Astrophysics Data System (ADS)

    Bauer, M.; Mathieu, C.; Demokritov, S. O.; Hillebrands, B.; Kolodin, P. A.; Sure, S.; Dötsch, H.; Slavin, A. N.

    1997-04-01

    We have investigated the propagation of surface and backward volume spin waves (BVSW) with the in-plane wavevector k∥=10-900 cm-1 excited by microwaves in YIG and Lu2.04Bi0.96Fe5O12 (LBIG) films with the film thicknesses 5 and 1.5 μm, respectively. In all cases the magnetization and k∥ were in the film plane. The frequencies of the spin wave excitations as well as the spatial distribution of their intensities in the linear and in the nonlinear excitation regime were measured by means of a fully automated, high-stabilization, small-angle Brillouin light scattering (BLS) setup with a spatial resolution of 30 μm. It is well known1 that in the case of BVSW modes, the Lighthill criterion2 for modulational instability is fulfilled for both the longitudinal and the transverse perturbations of the initially constant-amplitude wave beam. Therefore, this mode is very much suitable for the investigation of the evolution of a plane-front, constant-amplitude initial beam, and for a direct experimental study of two-dimensional nonlinear diffraction effects of the beam leading to self-focusing. The garnet films with in-plane dimensions of 2×10 mm2 were grown by liquid phase epitaxy onto a single crystalline (111)-oriented gallium gadolinium garnet substrate. Two strip antennas, 35 μm wide and situated at the ends of the films, were used for the excitation of the spin waves and for monitoring. The working frequency was 8.10 GHz. Special efforts were taken to minimize the beam divergence due to the finite length of the input antenna. For all nonlinear studies the initial angular beam divergence was not larger than Θmax=0.05 rad. In the linear regime the attenuation factor was measured, and the reflection of the spin waves from the sample boundaries was studied. We also observed the interference between the two lowest order lateral modes having different initial spatial distributions of the magnetization. The BLS technique was shown to provide a signal to noise ratio

  19. Characterization of Nanostructured Polymer Films

    DTIC Science & Technology

    2014-12-23

    of the film for complete polymer chain relaxation, including relaxation of surface features . The presence of intact surface globules at a substrate...AFRL-OSR-VA-TR-2015-0059 Characterization of Nanostructured Polymer Films RODNEY PRIESTLEY TRUSTEES OF PRINCETON UNIVERSITY Final Report 12/23/2014...Report 3. DATES COVERED (From - To) 06/01/2012-08/31/2014 4. TITLE AND SUBTITLE Characterization of Nanostructured Polymer Films 5a. CONTRACT

  20. 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.

  1. 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.

  2. 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.

  3. Drying of thin colloidal films

    NASA Astrophysics Data System (ADS)

    Routh, Alexander F.

    2013-04-01

    When thin films of colloidal fluids are dried, a range of transitions are observed and the final film profile is found to depend on the processes that occur during the drying step. This article describes the drying process, initially concentrating on the various transitions. Particles are seen to initially consolidate at the edge of a drying droplet, the so-called coffee-ring effect. Flow is seen to be from the centre of the drop towards the edge and a front of close-packed particles passes horizontally across the film. Just behind the particle front the now solid film often displays cracks and finally the film is observed to de-wet. These various transitions are explained, with particular reference to the capillary pressure which forms in the solidified region of the film. The reasons for cracking in thin films is explored as well as various methods to minimize its effect. Methods to obtain stratified coatings through a single application are considered for a one-dimensional drying problem and this is then extended to two-dimensional films. Different evaporative models are described, including the physical reason for enhanced evaporation at the edge of droplets. The various scenarios when evaporation is found to be uniform across a drying film are then explained. Finally different experimental techniques for examining the drying step are mentioned and the article ends with suggested areas that warrant further study.

  4. Slow rupture of polymer films

    NASA Astrophysics Data System (ADS)

    Kliakhandler, Igor

    2004-11-01

    Bursting of soap film is a fast and fascinating process. It turns out that certain polymer films rupture in a somewhat similar fashion, but much slower. The slowness of the process allows one to study the rupture of polymer films with details. The rupture process in Hele-Shaw-like fashion shows remarkable properties, and is a very simple system. It turns out that propagation speed of the rupture is a function of the film thickness, and rheologic properties of the polymer. Experimental results will be compared with theory, together with demonstration of the experiment.

  5. Evaluation of the Blood Film.

    PubMed

    Campbell, Terry W

    2015-09-01

    Evaluation of hemic cell morphology in stained blood film may be the most important part of the hematologic evaluation of exotic animals. The blood film provides important information regarding red blood cell abnormalities, such as changes in cell shape and color, presence of inclusions, and, in the case of lower vertebrates, changes in the position of the cell nucleus. Stained blood film also provides information about changes in leukocyte numbers and morphology, and shows important hemic features of mammalian platelets and the thrombocytes of lower vertebrates. The blood film is needed in the detection and identification of blood parasites.

  6. Oxide Films for RF Applications

    DTIC Science & Technology

    2008-07-01

    structured thin film superlattices of (AEO)m( TiO2 )n - type with varying m and n numbers in order to generate a homologous series of materials having...mechanisms in MBE oxide films The proposed goal was to identify, isolate, and reduce sources of loss in thin film dielectrics. It is important to note...that the loss in bulk single crystals is often orders of magnitude below that of their thin film counterparts. It is believed that defects in thin

  7. 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.

  8. "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…

  9. 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.

  10. 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.

  11. 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.

  12. Plasma deposition of organic thin films: Control of film chemistry

    SciTech Connect

    Ratner, B.D.

    1993-12-31

    Plasma deposition of thin, polymeric films represent a versatile surface modification technology. Although these thin films are exploited for many applications, complaints heard about plasma deposited films are that their structures are uncharacterizable, that organic functionality is lost in their production and that reproducibility is difficult. Recently, new methods for film production, reactor control and surface characterization have led to well characterized plasma deposited thin polymeric films (PDTPF) with defined structure and organic functionality. Such PDTPF often closely resemble conventionally prepared homopolymers. Methods that can be used to control the chemistry of PDTPF are the minimization of the plasma power, pulsing the RF field to reduce the {open_quotes}plasma on{close_quotes} time, use of a Faraday cage to reduce electron bombardment, positioning the sample downfield from the glow zone, the use of monomers containing polymerizable double bonds and the use of a cold substrate to condense vapor simultaneously with plasma deposition.

  13. Antireflective polyimide based films

    NASA Astrophysics Data System (ADS)

    Cao, Yuanmei

    The goal of this work was to prepare antireflective and anti-abrasion films using polyimide and organically modified silica nanoparticle thin films. A series of thin film were prepared from colorless and soluble polyimide with organically modified silica colloids via a solution casting method. The polyimide was selected for its optical properties. Three type of organically modified silica nanoparticles were prepared by grafting polysiloxane, polyfluoroester and fluoroalkyl groups onto silica nanoparticles. The molecular weight of the polysiloxane, polyfluoroester and the amount of fluorinated alkyl groups were varied. The organically modified silica colloids were characterized by TEM, DLS, FTIR, 1H NMR, solid state 13C NMR and solid state 29Si NMR. The coatings were characterized by UV-Vis transmittance spectra and SEM. The effect of modified silica loading, the molecular weight of polymer and type of solvent on AR properties were studied. An enhancement in antireflective activity was observed for 1 wt% LPDMS modified (low molecular weight) silica coatings, 3 wt% fluorosilica-10 and 3% L-MPS-PF-SILICA nanoparticles (low molecular weight polyfluoroester modified silica) in dimethylacetamide (DMAc). In comparison with cyclopentanone (CPT), DMAc favors migration of silica particles towards coating-air interface giving higher transmittance. The migration of particles to the surface and consequent increased surface roughness were observed by SEM. The present study suggested a roll to roll solution casting method to create antireflective coatings. This approach had potential to be used for a one-step large-scale manufacturing of antireflective coating. Four acrylated bismaleimide were made via two-step process. The first step involved the solution imidization to form hydroxylated bismaleimide. In the second step, hydroxylated bismaleimide was reacted with acryloyl chloride to form acrylated bismaleimide. The acrylated bismaleimide were characterized by FTIR, 1H NMR, 13C

  14. 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.

  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. Cardiovascular Cine Film Quality

    NASA Astrophysics Data System (ADS)

    Scheid, Carl C.

    1983-12-01

    The detection of a cardiovascular stenosis involves the complex interaction of technique selection, system performance and anatomy. Technique selection for instance involves choosing the correct focal spot, pulse width, KVp, and frame rate for a given patient and projection angle. In order to provide guidance in this selection process, these variables were investigated in terms of their impact on image quality. Conclusions which were confirmed clinically are summarized in terms of recommended techniques for a range of patient sizes. The confirmation includes clinical films which demonstrates the effects of parameter changes.

  17. Carbonaceous film coating

    DOEpatents

    Maya, L.

    1988-04-27

    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.

  18. Turbine airfoil film cooling

    NASA Technical Reports Server (NTRS)

    Hylton, Larry D.

    1986-01-01

    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.

  19. High Performance YBCO Films

    DTIC Science & Technology

    1992-07-01

    growing high quality MgO films on SrF2 substrates is the oxygen partial pressure during the growth. The x-ray data presented in Fig. 13 indicates a...fluo-ide and quartz substrates. The best result with two buffer layers (MgO and YSZ) on SrF2 was an onset temperature (Tc) of 82K and a transition...With a YSZ buffer an onset temperature of 85K and a transition width of 5K was achieved. Recent success was demonstrated by Neocera ( under a NASA

  20. A Film Canister Colorimeter

    NASA Astrophysics Data System (ADS)

    Gordon, James; James, Alan; Harman, Stephanie; Weiss, Kristen

    2002-08-01

    A low-cost, low-tech colorimeter was constructed from a film canister. The light source and filter monochromator was an interchangeable LED. The detector for this system was a voltage-divider circuit composed of a photoresistor in series with a fixed resistor. 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 the LED. Comparisons were made between this instrument and three commercial spectrometers and colorimeters.

  1. 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.

  2. 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.

  3. 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.

  4. ADVANCED THIN-FILM SOLAR CELLS.

    DTIC Science & Technology

    SEMICONDUCTING FILMS), (* SOLAR CELLS , MANUFACTURING, GALLIUM ALLOYS, ARSENIC ALLOYS, PLATINUM, OXIDES, TRANSPORT PROPERTIES, MOLYBDENUM, METAL FILMS, COPPER, HYDROGEN, GERMANIUM ALLOYS, TIN ALLOYS, ZINC, CRYSTAL GROWTH.

  5. 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.

  6. 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

  7. 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.

  8. Cinemabilia; Catalogue of Film Literature.

    ERIC Educational Resources Information Center

    Cinemabilia, New York, NY.

    The catalog lists and briefly annotates more than 3,500 current, second-hand, and out-of-print books about film that are available from Cinemabilia, New York City. The catalog is divided into 37 categories. The section on special genre lists works on horror, science fiction, Westerns, and Tarzan films, ranging from "Drums of Fu-Manchu" to "Movie…

  9. 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.

  10. 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…

  11. Improved Dielectric Films For Capacitors

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S.; Lewis, Carol R.; Cygan, Peter J.; Jow, T. Richard

    1994-01-01

    Dielectric films made from blends of some commercially available high-dielectric-constant cyanoresins with each other and with cellulose triacetate (CTA) have both high dielectric constants and high breakdown strengths. Dielectric constants as high as 16.2. Films used to produce high-energy-density capacitors.

  12. 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'…

  13. Methods of Producing Thin Films,

    DTIC Science & Technology

    The report describes various methods of producing thin films , especially for microelectronics. In addition to the classical methods of forming thin ... films by vacuum vapor deposition, it also describes processes of diode sputtering and modern methods of cathode sputtering by means of a third

  14. Films for Sociology, First Edition.

    ERIC Educational Resources Information Center

    LeBeau, Bryan, Comp.

    This catalog contains a listing of over 1,000 16mm films of interest to students, teachers, and researchers in sociology. Whenever possible, content reflects current trends toward increased interdisciplinary investigation. In the main body of the catalog, the films are listed alphabetically by title. For each entry, information is given on…

  15. 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.

  16. 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.

  17. 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.

  18. Films in the ESL Classroom.

    ERIC Educational Resources Information Center

    Gex, Judith Coppock

    The most important consideration with regard to classroom use of films in an English as a second language (ESL) class is that it should be previewed by the teacher and selected according to criteria such as those suggested here. In example, short silent films that are uncluttered in appearance are good vehicles for teaching vocabulary. Some…

  19. 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.

  20. 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…

  1. 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)

  2. Magnetochromatic thin-film microplates.

    PubMed

    He, Le; Janner, Michael; Lu, Qipeng; Wang, Mingsheng; Ma, Hua; Yin, Yadong

    2015-01-07

    A new type of magnetochromatic material is developed based on thin-film interference of microplates self-assembled from super-paramagnetic nanocrystals. Dynamic optical tuning can be achieved through orientational manipulation of free-standing super-paramagnetic thin-film microplates using external magnetic fields.

  3. Thin Film Inorganic Electrochemical Systems.

    DTIC Science & Technology

    1995-07-01

    determined that thin film cathodes of LiCoO2 can be readily performed by either spray pyrolysis or spin coating . These cathodes are electrochemically...active. We have also determined that thin film anodes of Li4Ti5O12 can be prepared by spray pyrolysis or spin coating . These anodes are also

  4. 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)

  5. 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.

  6. 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…

  7. 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…

  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. 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.

  10. Thermopower of thin iron films

    NASA Astrophysics Data System (ADS)

    Schepis, Randy; Schröder, Klaus

    1992-02-01

    Thin iron films were prepared by evaporation in a high vacuum system (pressure in the 10 -5 MPa range). The thermopower was measured in situ near room temperature as a function of film thickness. Iron films with rather high resistivity values showed a strong thickness effect of the Seeback coefficient, S, with the difference between S (bulk) and S (film) reaching values of up to (19±3) μV/K for a sample 5 nm thick. The difference between S (bulk) and S (film) decreased with increasing d values. However, a sample with a resistance value of 50 μΩ cm at d = 5 n had an S value which differed by less than 3 μV/K from S (bulk).

  11. A new radiochromic dosimeter film

    NASA Astrophysics Data System (ADS)

    Sidney, L. N.; Lynch, D. C.; Willet, P. S.

    By employing acid-sensitive leuco dyes in a chlorine-containing polymer matrix, a new radiochromic dosimeter film has been developed for gamma, electron beam, and ultraviolet radiation. These dosimeter films undergo a color change from colorless to royal blue, red fuchsia, or black, depending on dye selection, and have been characterized using a visible spectrophotometer over an absorbed dose range of 1 to 100 kGy. The primary features of the film are improved color stability before and after irradiation, whether stored in the dark or under artificial lights, and improved moisture resistance. The effects of absorbed dose, dose rate, and storage conditions on dosimeter performance are discussed. The dosimeter material may be produced as a free film or coated onto a transparent substrate and optionally backed with adhesive. Potential applications for these materials include gamma sterilization indicator films for food and medical products, electron beam dosimeters, and in-line radiation monitors for electron beam and ultraviolet processing.

  12. 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.

  13. 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.

  14. 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.

  15. Contributions of Film Introductions and Film Summaries to Learning from Instructional Films.

    ERIC Educational Resources Information Center

    Lathrop, C. W., Jr.; Norford, C. A.

    An exploratory study of the contribution to learning of typical introductory and summarizing sequences in instructional films underlined the need for further experimental work to determine what kinds of introductory and concluding sequences are most useful in promoting learning from films. The first part of the study was concerned with film…

  16. Film thickness for different regimes of fluid-film lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1980-01-01

    Film thickness equations are provided for four fluid-film lubrication regimes found in elliptical contacts. These regimes are isoviscous-rigid; viscous-rigid; elastohydrodynamic lubrication of low-elastic-modulus materials (soft EHL), or isoviscous-elastic; and elastohydrodynamic lubrication of high-elastic-modulus materials (hard EHL), or viscous-elastic. The influence or lack of influence of elastic and viscous effects is the factor that distinguishes these regimes. The results are presented as a map of the lubrication regimes, with film thickness contours on a log-log grid of the viscosity and elasticity for three values of the ellipticity parameter.

  17. Effects on film structure on mechanical and adhesion properties of latex films

    SciTech Connect

    Charmeau, J.Y.; Holl, Y.; Kientz, E.

    1995-12-31

    In order to investigate the effect of the particular structure of latex films on mechanical (stress-strain behavior) and adhesion (measured by peeling) properties, this work compares these characteristics for latex films and corresponding {open_quotes}solution films{close_quotes}. Solution films were obtained by dissolving the latex film in an appropriate solvent and forming a new film by evaporating the solvent. Four different systems were studied. It was shown that latex films have Young`s moduli systematically much higher than the corresponding solution films. This is due to the fact that the hydrophilic shells of the latex particles form a continuous phase in the latex film which increases the modulus thanks to polar interactions. However, adhesion energy for latex films is always smaller than for solution films. This is interpreted in terms of structure of the film-support interface and dissipative processes within the bulk of the films.

  18. Ferromagnetic thin films

    DOEpatents

    Krishnan, K.M.

    1994-12-20

    A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

  19. Thin film hydrogen sensor

    DOEpatents

    Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

    1994-11-22

    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. 6 figs.

  20. Ferromagnetic thin films

    DOEpatents

    Krishnan, Kannan M.

    1994-01-01

    A ferromagnetic .delta.-Mn.sub.1-x Ga.sub.x thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of .delta.-Mn.sub.1-x Ga.sub.x overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of .delta.-Mn.sub.1-x Ga.sub.x and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4 .+-.0.05.

  1. Polyimide Aerogel Thin Films

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  2. Antimicrobial edible films and coatings.

    PubMed

    Cagri, Arzu; Ustunol, Zeynep; Ryser, Elliot T

    2004-04-01

    Increasing consumer demand for microbiologically safer foods, greater convenience, smaller packages, and longer product shelf life is forcing the industry to develop new food-processing, cooking, handling, and packaging strategies. Nonfluid ready-to-eat foods are frequently exposed to postprocess surface contamination, leading to a reduction in shelf life. The food industry has at its disposal a wide range of nonedible polypropylene- and polyethylene-based packaging materials and various biodegradable protein- and polysaccharide-based edible films that can potentially serve as packaging materials. Research on the use of edible films as packaging materials continues because of the potential for these films to enhance food quality, food safety, and product shelf life. Besides acting as a barrier against mass diffusion (moisture, gases, and volatiles), edible films can serve as carriers for a wide range of food additives, including flavoring agents, antioxidants, vitamins, and colorants. When antimicrobial agents such as benzoic acid, sorbic acid, propionic acid, lactic acid, nisin, and lysozyme have been incorporated into edible films, such films retarded surface growth of bacteria, yeasts, and molds on a wide range of products, including meats and cheeses. Various antimicrobial edible films have been developed to minimize growth of spoilage and pathogenic microorganisms, including Listeria monocytogenes, which may contaminate the surface of cooked ready-to-eat foods after processing. Here, we review the various types of protein-based (wheat gluten, collagen, corn zein, soy, casein, and whey protein), polysaccharide-based (cellulose, chitosan, alginate, starch, pectin, and dextrin), and lipid-based (waxes, acylglycerols, and fatty acids) edible films and a wide range of antimicrobial agents that have been or could potentially be incorporated into such films during manufacture to enhance the safety and shelf life of ready-to-eat foods.

  3. Language, Culture, and the Feature Film.

    ERIC Educational Resources Information Center

    Straub, Hans

    2002-01-01

    Suggests that one way to provide cultural contexts for language learning is by using feature films for instructional purposes. Highlights the benefits of feature films, discusses the selection of films, and describes a process for using feature films in the language classroom. (Author/VWL)

  4. FILM WORKSHOP SUCCESSFUL WITH TSU STUDENTS.

    ERIC Educational Resources Information Center

    BAHRENBERG, JIM

    AN UPWARD BOUND FILM WORKSHOP AT TEXAS SOUTHERN UNIVERSITY EXPOSED STUDENTS TO FILMS AS A CREATIVE ART FORM, A MEANS OF COMMUNICATION, AND A BASIS FOR DISCUSSING VALUES. IN ADDITION TO VIEWING SEVERAL SHORT, PROFESSIONALLY-DEVELOPED FILMS, STUDENTS WROTE AND PRODUCED TWO OF THEIR OWN. ONE STUDENT-PRODUCED FILM--A LIGHT SHOW--ILLUMINATED THE UNITY…

  5. EFFECT OF REPETITIVE FILM SHOWINGS ON LEARNING.

    ERIC Educational Resources Information Center

    MCTAVISH, C.L.; AND OTHERS

    A DETERMINATION OF THE INCREMENT IN LEARNING ATTRIBUTABLE SOLELY TO ONE, TWO, AND THREE REPETITIONS OF A FILM OVER AND ABOVE A SINGLE SHOWING WAS INVESTIGATED. THE SUBJECTS WERE 319 COLLEGE FRESHMEN WHO WERE DIVIDED INTO FOUR GROUPS AND WHO WERE SHOWN FOUR GENERAL SCIENCE FILMS. EACH GROUP SAW ONE OF THE FILMS ONCE, A SECOND FILM TWICE, A THIRD…

  6. Geoflicks Reviewed--Films about Hawaiian Volcanoes.

    ERIC Educational Resources Information Center

    Bykerk-Kauffman, Ann

    1994-01-01

    Reviews 11 films on volcanic eruptions in the United States. Films are given a one- to five-star rating and the film's year, length, source and price are listed. Top films include "Inside Hawaiian Volcanoes" and "Kilauea: Close up of an Active Volcano." (AIM)

  7. Historical Films in the Latin Classroom.

    ERIC Educational Resources Information Center

    Buller, Jeffrey L.

    Guidelines and lesson plans are presented for teachers of Latin using historical films as instructional and support materials. A discussion of the use of historical films addresses these issues in classroom practice: the legality of using films in the classroom (copyrights); techniques for using historical films as sources of cultural information;…

  8. "Space slitter" for film or tape

    NASA Technical Reports Server (NTRS)

    Johnson, W. H.

    1978-01-01

    Device cuts film or tape into strips by guiding film in channel under cutting blades. Device is operated by lifting pressure bar to insert blades into film. Film is then pulled through blades. Cutter has potential uses in advertising, commercial art, and publishing fields.

  9. 19 CFR 12.41 - Prohibited films.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Prohibited films. 12.41 Section 12.41 Customs... SPECIAL CLASSES OF MERCHANDISE Immoral Articles § 12.41 Prohibited films. (a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any...

  10. 19 CFR 12.41 - Prohibited films.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Prohibited films. 12.41 Section 12.41 Customs... SPECIAL CLASSES OF MERCHANDISE Immoral Articles § 12.41 Prohibited films. (a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any...

  11. 19 CFR 12.41 - Prohibited films.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Prohibited films. 12.41 Section 12.41 Customs... SPECIAL CLASSES OF MERCHANDISE Immoral Articles § 12.41 Prohibited films. (a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any...

  12. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  13. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  14. 19 CFR 12.41 - Prohibited films.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Prohibited films. 12.41 Section 12.41 Customs... SPECIAL CLASSES OF MERCHANDISE Immoral Articles § 12.41 Prohibited films. (a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any...

  15. 19 CFR 12.41 - Prohibited films.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Prohibited films. 12.41 Section 12.41 Customs... SPECIAL CLASSES OF MERCHANDISE Immoral Articles § 12.41 Prohibited films. (a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any...

  16. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  17. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  18. 16 CFR 501.1 - Camera film.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk...

  19. Using Popular Children's Films in Science

    ERIC Educational Resources Information Center

    Wadsworth, Elle; Croker, Stev; Harrison, Tim

    2012-01-01

    Watching films is a common activity for children outside of school, and incorporating popular films that contain scientific references has the potential to spark interest in the classroom. Clips rather than entire films can be used, as the children will maintain focus on the lesson objectives while being excited by the appeal of the film. The use…

  20. Subjective Sexual Arousal to Films of Masturbation

    ERIC Educational Resources Information Center

    Mosher, Donald L.; Abramson, Paul R.

    1977-01-01

    A film of a male or female masturbating was viewed by 96 males and 102 females. Males reported the highest level of sexual arousal to the female film and the lowest level of arousal to the male film. Females were sexually aroused by both films. (Author)

  1. A 3M high temperature dielectric film

    NASA Technical Reports Server (NTRS)

    Hampl, Edward, Jr.

    1994-01-01

    The performance characteristics of a dielectric film are summarized. Additionally, the film's environmental and chemical properties are listed: low shrinkage to 300 C; moisture insensitive; low outgassing under vacuum; excellent surface qualities--easy metallization of film; flame retardant; and low smoke generation. A series of graphs that display the performance characteristics of the film are also presented.

  2. Focus on Young Film Makers: Student Film Making--Types and Techniques.

    ERIC Educational Resources Information Center

    Putsch, Henry E.

    1968-01-01

    Brief descriptions of 10 styles of student film making include references to specific films employing the techniques. The styles of film making listed are animation, pixillation animation, collage, draw-on, documentary, bio-documentary, story line, impressionistic, commercials, and the school film. Directions for submitting films to the Young Film…

  3. American Film Genres: Approaches to a Critical Theory of Popular Film.

    ERIC Educational Resources Information Center

    Kaminsky, Stuart M.

    This book is divided into twelve sections and contains photographs from many of the films discussed. The introduction defines film genre and describes the general theories behind this book; "The Individual Film" analyzes the film "Little Caesar" as it relates to the genre of gangster films; "Comparative Forms"…

  4. Surface wrinkling on polydopamine film

    NASA Astrophysics Data System (ADS)

    Meng, Jieyun; Xie, Jixun; Han, Xue; Lu, Conghua

    2016-05-01

    In this paper, we report a non-lithographic strategy to realize surface patterns on polydopamine films. It is based on surface wrinkling, which is induced on polydopamine (PDA) films that are grown on uniaxially pre-strained polydimethylsiloxane (PDMS) substrates through self-polymerization of dopamine, followed by the pre-strain release. We investigate the influences of the experimental conditions including polymerization time, prestrain and the dopamine solution concentration on the wrinkling patterns. Furthermore, we take advantage of the reducibility of PDA to fabricate silver nanoparticle-deposited PDA films with surface-wrinkled patterns, which may have potential applications in the related fields.

  5. Ultrathin Polymer Films for Microlithography

    DTIC Science & Technology

    1988-07-13

    exposure the PINAA was developed in a solution made of 3:7 cellosolve : methanol for 13 seconds. Cellosolve was chosen because it is strong enough to...can achieve on thicker resist (> 100 nm) for the same exposure conditions. Recently, we have exposed 14.3 nrm L-B PMMA films on a high resolution...Polymer Films LB PMMA Spin-Cast PNMA Spin-Cast Novolac (10 wafers) (5 wafers) (5 wafers) Film Thickness 14.3 nrm 14 nrm 22 nm Pinhole Density < 10/cm 2

  6. Surface nanostructures in manganite films.

    PubMed

    Gambardella, A; Graziosi, P; Bergenti, I; Prezioso, M; Pullini, D; Milita, S; Biscarini, F; Dediu, V A

    2014-06-19

    Ultrathin manganite films are widely used as active electrodes in organic spintronic devices. In this study, a scanning tunnelling microscopy (STM) investigation with atomic resolution revealed previously unknown surface features consisting of small non-stoichiometric islands. Based upon this evidence, a new mechanism for the growth of these complex materials is proposed. It is suggested that the non-stoichiometric islands result from nucleation centres that are below the critical threshold size required for stoichiometric crystalline growth. These islands represent a kinetic intermediate of single-layer growth regardless of the film thickness, and should be considered and possibly controlled in manganite thin-film applications.

  7. Film boiling of mercury droplets

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Schoessow, G. J.; Chmielewski, C. E.

    1975-01-01

    Vaporization times of mercury droplets in Leidenfrost film boiling on a flat horizontal plate are measured in an air atmosphere. Extreme care was used to prevent large amplitude droplet vibrations and surface wetting; therefore, these data can be compared to film boiling theory. Diffusion from the upper surface of the drop appears as a dominant mode of mass transfer from the drop. A closed-form analytical film boiling theory is developed to account for the diffusive evaporation. Reasonable agreement between data and theory is seen.

  8. Tailoring nanocrystalline diamond film properties

    DOEpatents

    Gruen, Dieter M.; McCauley, Thomas G.; Zhou, Dan; Krauss, Alan R.

    2003-07-15

    A method for controlling the crystallite size and growth rate of plasma-deposited diamond films. A plasma is established at a pressure in excess of about 55 Torr with controlled concentrations of hydrogen up to about 98% by volume, of unsubstituted hydrocarbons up to about 3% by volume and an inert gas of one or more of the noble gases and nitrogen up to about 98% by volume. The volume ratio of inert gas to hydrogen is preferably maintained at greater than about 4, to deposit a diamond film on a suitable substrate. The diamond film is deposited with a predetermined crystallite size and at a predetermined growth rate.

  9. Photovoltaic properties of polymer films

    NASA Astrophysics Data System (ADS)

    Reucroft, P. J.; Ullal, H.

    1980-03-01

    The effect of metal electrode and film thickness on the photovoltaic energy conversion efficiency in (1:1) mole ratio films of poly (N-vinylcarbazole) (PVK) and 2,4,7-trinitrofluorenone (TNF) has been investigated. Low work function metals increase the Schottky barrier height which leads to increases in the photovoltaic energy conversion efficiency. A ten-fold decrease in film thickness produces a thousand-fold increase in photovoltaic energy conversion efficiency. A theoretical model which assumes that the photovoltaic current is limited by Child's law predicts photovoltaic efficiencies which are in good agreement with the measured efficiencies.

  10. Surface Nanostructures in Manganite Films

    PubMed Central

    Gambardella, A.; Graziosi, P.; Bergenti, I.; Prezioso, M.; Pullini, D.; Milita, S.; Biscarini, F.; Dediu, V. A.

    2014-01-01

    Ultrathin manganite films are widely used as active electrodes in organic spintronic devices. In this study, a scanning tunnelling microscopy (STM) investigation with atomic resolution revealed previously unknown surface features consisting of small non-stoichiometric islands. Based upon this evidence, a new mechanism for the growth of these complex materials is proposed. It is suggested that the non-stoichiometric islands result from nucleation centres that are below the critical threshold size required for stoichiometric crystalline growth. These islands represent a kinetic intermediate of single-layer growth regardless of the film thickness, and should be considered and possibly controlled in manganite thin-film applications. PMID:24941969

  11. Liquid-film electron stripper

    DOEpatents

    Leemann, B.T.; Yourd, R.B.

    1982-03-09

    A thin freestanding oil film is produced in vacuum by directing an oil stream radially inward to the hollow-ground sharp outer edge of a rotating disc. The sides of the edge are roughened somewhat to aid in dispersing oil from the disc. Oil is removed from the surface of disc to prevent formation of oil droplets which might spin off the disc and disrupt the oil film. An ion beam is directed through the thin oil film so that electrons are stripped from the ions to increase their charge.

  12. Liquid-film electron stripper

    DOEpatents

    Leemann, Beat T.; Yourd, Roland B.

    1984-01-01

    A thin freestanding oil film is produced in vacuum by directing an oil stream radially inward to the hollow-ground sharp outer edge of a rotating disc. The sides of the edge are roughened somewhat to aid in dispersing oil from the disc. Oil is removed from the surface of disc to prevent formation of oil droplets which might spin off the disc and disrupt the oil film. An ion beam is directed through the thin oil film so that electrons are stripped from the ions to increase their charge.

  13. Film boiling of mercury droplets

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Schoessow, G. J.; Chmielewski, C. E.

    1975-01-01

    Vaporization times of mercury droplets in Leidenfrost film boiling on a flat horizontal plate are measured in an air atmosphere. Extreme care was used to prevent large amplitude droplet vibrations and surface wetting; therefore, these data can be compared to film boiling theory. For these data, diffusion from the upper surface of the drop is a dominant mode of mass transfer from the drop. A closed-form analytical film boiling theory is developed to account for the diffusive evaporation. Reasonable agreement between data and theory is seen.

  14. Vapor deposition of thin films

    DOEpatents

    Smith, David C.; Pattillo, Stevan G.; Laia, Jr., Joseph R.; Sattelberger, Alfred P.

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  15. Electrospun bismuth ferrite nanofibers for potential applications in ferroelectric photovoltaic devices.

    PubMed

    Fei, Linfeng; Hu, Yongming; Li, Xing; Song, Ruobing; Sun, Li; Huang, Haitao; Gu, Haoshuang; Chan, Helen L W; Wang, Yu

    2015-02-18

    Bismuth ferrite (BFO) nanofibers were synthesized via a sol-gel-based electrospinning process followed by thermal treatment. The influences of processing conditions on the final structure of the samples were investigated. Nanofibers prepared under optimized conditions were found to have a perovskite structure with good quality of crystallization and free of impurity phase. Ferroelectric and piezoelectric responses were obtained from individual nanofiber measured on a piezoelectric force microscope. A prototype photovoltaic device using laterally aligned BFO nanofibers and interdigital electrodes was developed and its performance was examined on a standard photovoltaic system. The BFO nanofibers were found to exhibit an excellent ferroelectric photovoltaic property with the photocurrent several times larger than the literature data obtained on BFO thin films.

  16. Importance of combining convection with film cooling

    NASA Technical Reports Server (NTRS)

    Colladay, R. S.

    1971-01-01

    The interaction of film and convection cooling and its effect on wall cooling efficiency is investigated analytically for two cooling schemes for advanced gas turbine applications. The two schemes are full coverage- and counterflow-film cooling. In full coverage film cooling, the cooling air issues from a large number of small discrete holes in the surface. Counterflow film cooling is a film-convection scheme with film injection from a slot geometry. The results indicate that it is beneficial to utilize as much of the cooling air heat sink as possible for convection cooling prior to ejecting it as a film.

  17. Importance of combining convection with film cooling.

    NASA Technical Reports Server (NTRS)

    Colladay, R. S.

    1972-01-01

    The interaction of film and convection cooling and its effect on wall cooling efficiency is investigated analytically for two cooling schemes for advanced gas turbine applications. The two schemes are full coverage- and counterflow-film cooling. In full coverage film cooling, the cooling air issues from a large number of small discrete holes in the surface. Counterflow film cooling is a film-convection scheme with film injection from a slot geometry. The results indicate that it is beneficial to utilize as much of the cooling air heat sink as possible for convection cooling prior to ejecting it as a film.

  18. Optoelectronic Nanocomposite Materials for Thin Film Photovoltaics

    DTIC Science & Technology

    2012-06-01

    CdTe and ZnO single-phase thin films , nanocomposite films ...for the CdTe -ZnO thin film system under these conditions. c. Optical Absorption The films produced in the present study consistently exhibited...optical absorbance spectra collected from CdTe -ZnO multilayer nanocomposite thin films . The effect of CdTe layer thickness used per deposition cycle

  19. Thin film characterization using spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.

    1990-01-01

    The application of the multiple angle and wavelength (MAW) technique to measure the dielectric function of semiconducting films is discussed. This technique evaluates unambiguously the complex dielectric function, epsilon (E), of the film without any pre-assumptions. In some cases the effective medium approximation (EMA) was used to determine the volume fraction of the film components. Application of the MAW technique to several semiconducting films was published previously. Different applications and examples are given, including metal and insulator films.

  20. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Jow, T. Richard (Inventor)

    1995-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  1. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Jow, T. Richard (Inventor)

    1993-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  2. The Art of Teaching Social Studies with Film

    ERIC Educational Resources Information Center

    Russell, William B., III

    2012-01-01

    Teaching with film is a powerful and meaningful instructional strategy. This article discusses five classroom-tested methods for teaching with film: (1) film as a visual textbook, (2) film as a depicter of atmosphere, (3) film as an analogy, (4) film as a historiography, and (5) film as a springboard. Each of the methods discussed includes…

  3. Film Growth on Nanoporous Substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Xue; Joy, James; Zhao, Chenwei; Xu, J. M.; Valles, James

    Self-ordered nanoporous anodic aluminum oxide (AAO) provides an easy way to fabricate nano structured material, such as nano wires and nano particles. We employ AAO as substrates and focus on the thermally evaporated film growth on the surface of the substrate. With various materials deposited onto the substrate, we find the films show different structures, e,g. ordered array of nano particles for Lead and nanohoneycomb structure for Silver. We relate the differing behaviors to the difference of surface energy and diffusion constant. To verify this, the effect of substrate temperature on the film growth has been explored and the structure of the film has been successfully changed through the process. We are grateful for the support of NSF Grants No. DMR-1307290.

  4. The thin film microwave iris

    NASA Technical Reports Server (NTRS)

    Ramey, R. L.; Landes, H. S.; Manus, E. A.

    1972-01-01

    Development of waveguide iris for microwave coupling applications using thin film techniques is discussed. Production process and installation of iris are described. Iris improves power transmission properties of waveguide window.

  5. Curved film cooling admission tube

    NASA Technical Reports Server (NTRS)

    Graham, R. W.; Papell, S. S. (Inventor)

    1980-01-01

    Effective film cooling to protect a wall surface from a hot fluid which impinges on or flows along the surface is provided. A film of cooling fluid having increased area is provided by changing the direction of a stream of cooling fluid through an angle of from 135 deg. to 165 deg. before injecting it through the wall into the hot flowing gas. The 1, cooling fluid is injected from an orifice through a wall into a hot flowing gas at an angle to form a cooling fluid film. Cooling fluid is supplied to the orifice from a cooling fluid source via a turbulence control passageway having a curved portion between two straight portions. The angle through which the direction of the cooling fluid is turned results in less mixing of the cooling fluid with the hot gas, thereby substantially increasing the length of the film in a downstream direction.

  6. Applications of film thickness equations

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1983-01-01

    A number of applications of elastohydrodynamic film thickness expressions were considered. The motion of a steel ball over steel surfaces presenting varying degrees of conformity was examined. The equation for minimum film thickness in elliptical conjunctions under elastohydrodynamic conditions was applied to roller and ball bearings. An involute gear was also introduced, it was again found that the elliptical conjunction expression yielded a conservative estimate of the minimum film thickness. Continuously variable-speed drives like the Perbury gear, which present truly elliptical elastohydrodynamic conjunctions, are favored increasingly in mobile and static machinery. A representative elastohydrodynamic condition for this class of machinery is considered for power transmission equipment. The possibility of elastohydrodynamic films of water or oil forming between locomotive wheels and rails is examined. The important subject of traction on the railways is attracting considerable attention in various countries at the present time. The final example of a synovial joint introduced the equation developed for isoviscous-elastic regimes of lubrication.

  7. Captioned Films for the Deaf

    ERIC Educational Resources Information Center

    Norwood, Malcolm J.

    1976-01-01

    Described are the functions of the Captioned Films for the Deaf program, a free loan service of subtitled motion pictures similar in nature to the free loan service of Talking Books for the Blind. (SBH)

  8. Captioned Films for the Deaf.

    ERIC Educational Resources Information Center

    Boatner, Edmund Burke

    1981-01-01

    The history of Captioned Films for the Deaf, an agency now called Media for the Handicapped, is traced along with the contributions of individuals and groups which led to the eventual passage of legislation in 1959. (CL)

  9. Manganite films: Tuning phase diagrams

    NASA Astrophysics Data System (ADS)

    Mihailovic, Dragan

    2016-09-01

    Strain engineering can tune a manganite film into an antiferromagnetic insulating state whose extreme photo-susceptibility allows for the ordinary ferromagnetic metal state to then be transiently realized.

  10. Fabrication of amorphous diamond films

    DOEpatents

    Falabella, S.

    1995-12-12

    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.

  11. Antistatic additive for polyimide films

    NASA Technical Reports Server (NTRS)

    Sarbolouki, M. N.

    1978-01-01

    Thin polyimide films are given excellent antistatic properties even at high temperature by low-level loading with lithium salts. Extremely hygroscopic, these salts absorb a layer of atmospheric water that provides conductive paths allowing charges to dissipate.

  12. Interference Colors in Thin Films.

    ERIC Educational Resources Information Center

    Armstrong, H. L.

    1979-01-01

    Explains interference colors in thin films as being due to the removal, or considerable reduction, of a certain color by destructive inteference that results in the complementary color being seen. (GA)

  13. Measurement of opaque film thickness

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Jaarinen, J.; Reyes, C.; Oppenheim, I. C.; Favro, L. D.; Kuo, P. K.

    1987-01-01

    The theoretical and experimental framework for thickness measurements of thin metal films by low frequency thermal waves is described. Although it is assumed that the films are opaque and the substrates are comparatively poor thermal conductors, the theory is easily extended to other cases of technological interest. A brief description is given of the thermal waves and the experimental arrangement and parameters. The usefulness of the technique is illustrated for making absolute measurements of the thermal diffusivities of isotropic substrate materials. This measurement on pure elemental solids provides a check on the three dimensional theory in the limiting case of zero film thickness. The theoretical framework is then presented, along with numerical calculations and corresponding experimental results for the case of copper films on a glass substrate.

  14. Nanodynamics of ferroelectric ultrathin films.

    PubMed

    Zhang, Qingteng; Herchig, R; Ponomareva, I

    2011-10-21

    The nanodynamics of ferroelectric ultrathin films made of PbTi(0.6)Zr(0.4)TiO(3) alloy is explored via the use of a first-principles-based technique. Our atomistic simulations predict that the nanostripe domains which constitute the ground state of ferroelectric ultrathin films under most electric boundary conditions oscillate under a driving ac field. Furthermore, we find that the atomically thin wall, or nanowall, that separates the nanodomains with different polarization directions behaves as an elastic object and has a mass associated with it. The nanowall mass is size-dependent and gives rise to a unique size-driven transition from resonance to relaxational dynamics in ultrathin films. A general theory of nanodynamics in such films is developed and used to explain all computational findings. In addition, we find an unusual dynamical coupling between nanodomains and mechanical deformations that could potentially be used in ultrasensitive electromechanical nanosensors.

  15. Metallo-organic decomposition films

    NASA Technical Reports Server (NTRS)

    Gallagher, B. D.

    1985-01-01

    A summary of metallo-organic deposition (MOD) films for solar cells was presented. The MOD materials are metal ions compounded with organic radicals. The technology is evolving quickly for solar cell metallization. Silver compounds, especially silver neodecanoate, were developed which can be applied by thick-film screening, ink-jet printing, spin-on, spray, or dip methods. Some of the advantages of MOD are: high uniform metal content, lower firing temperatures, decomposition without leaving a carbon deposit or toxic materials, and a film that is stable under ambient conditions. Molecular design criteria were explained along with compounds formulated to date, and the accompanying reactions for these compounds. Phase stability and the other experimental and analytic results of MOD films were presented.

  16. Film holder for radiographing tubing

    DOEpatents

    Davis, Earl V.; Foster, Billy E.

    1976-01-01

    A film cassette is provided which may be easily placed about tubing or piping and readily held in place while radiographic inspection is performed. A pair of precurved light-impervious semi-rigid plastic sheets, hinged at one edge, enclose sheet film together with any metallic foils or screens. Other edges are made light-tight with removable caps, and the entire unit is held securely about the object to be radiographed with a releasable fastener such as a strip of Velcro.

  17. Science and film-making.

    PubMed

    Gouyon, Jean-Baptiste

    2016-01-01

    The essay reviews the literature, mostly historical, on the relationship between science and film-making, with a focus on the science documentary. It then discusses the circumstances of the emergence of the wildlife making-of documentary genre. The thesis examined here is that since the early days of cinema, film-making has evolved from being subordinate to science, to being an equal partner in the production of knowledge, controlled by non-scientists.

  18. Photoconductivity of thin organic films

    NASA Astrophysics Data System (ADS)

    Tkachenko, Nikolai V.; Chukharev, Vladimir; Kaplas, Petra; Tolkki, Antti; Efimov, Alexander; Haring, Kimmo; Viheriälä, Jukka; Niemi, Tapio; Lemmetyinen, Helge

    2010-04-01

    Thin organic films were deposited on silicon oxide surfaces with golden interdigitated electrodes (interelectrode gap was 2 μm), and the film resistivities were measured in dark and under white light illumination. The compounds selected for the measurements include molecules widely used in solar cell applications, such as polythiophene ( PHT), fullerene ( C60), pyrelene tetracarboxylic diimide ( PTCDI) and copper phthalocyanine ( CuPc), as well as molecules potentially interesting for photovoltaic applications, e.g. porphyrin-fullerene dyads. The films were deposited using thermal evaporation (e.g. for C60 and CuPc films), spin coating for PHT, and Langmuir-Schaeffer for the layer-by-layer deposition of porphyrin-fullerene dyads. The most conducting materials in the series are films of PHT and CuPc with resistivities 1.2 × 10 3 Ω m and 3 × 10 4 Ω m, respectively. Under light illumination resistivity of all films decreases, with the strongest light effect observed for PTCDI, for which resistivity decreases by 100 times, from 3.2 × 10 8 Ω m in dark to 3.1 × 10 6 Ω m under the light.

  19. Quality assurance in film radiography

    SciTech Connect

    Van Bellegem, L.; Vaessen, B.

    1993-12-31

    The ISO 9000 standards were originally developed during the 1980`s to provide uniform, worldwide quality assurance requirements. The EC (European Communities) adopted these standards as part of their modular approach to ``conformity assessment`` procedures, for several product categories. This includes the development of standards (specifications) which define what the purchaser wants and what the supplier agrees to provide, as well as quality system registration (certification) which increases confidence in the supplier`s ability to produce consistently. The requirements are typically most rigorous for regulated products that have a major impact on health and safety i.e film radiographic systems. This is the main reason for making available the necessary Q.C. tools in film radiography to comply with Q.A. specifications and guarantee the required consistent performance. These tools can only give satisfying support if they are dedicated, easy to use, precise and cost effective at the user`s level. The main topics for such a Q.A. package are: (1) standard for Film System classification for industrial radiography; (2) film system certification; and (3) standard for control of film processing by means of reference values i.e. pre-exposed film wedges and archiving quality control method.

  20. Variable temperature semiconductor film deposition

    DOEpatents

    Li, Xiaonan; Sheldon, Peter

    1998-01-01

    A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.