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Sample records for 0-5 5-10 10-15

  1. 5,10,15-Triferrocenylcorrole Complexes.

    PubMed

    Pomarico, Giuseppe; Galloni, Pierluca; Mandoj, Federica; Nardis, Sara; Stefanelli, Manuela; Vecchi, Andrea; Lentini, Sara; Cicero, Daniel O; Cui, Yan; Zeng, Lihan; Kadish, Karl M; Paolesse, Roberto

    2015-11-01

    Complexes of 5,10,15-triferrocenylcorrole were synthesized from the crude free-base corrole product obtained by the reaction of ferrocenyl aldehyde and pyrrole. Direct formation of the complex in this manner leads to an increase of the reaction yield by protecting the corrole ring toward oxidative decomposition. The procedure was successful and gave the expected product in the case of the copper and triphenylphosphinecobalt complexes, but an unexpected result was obtained in the case of the nickel derivative, where metal insertion led to a ring opening of the macrocycle at the 5 position, giving as a final product a linear tetrapyrrole nickel complex bearing two ferrocenyl groups. The purified 5,10,15-triferrocenylcorrole complexes have been fully characterized by a combination of spectroscopic methods, electrochemistry, spectroelectrochemistry, and density functional theory calculations. Copper derivatives of 10-monoferrocenyl- and 5,15-diferrocenylcorrole were prepared to investigate how the number and position of the ferrocenyl groups influenced the spectroscopic and electrochemical properties of the resulting complexes. A complete assignment of resonances in the (1)H and (13)C NMR spectra was performed for the cobalt and nickel complexes, and detailed electrochemical characterization was carried out to provide additional insight into the degree of communication between the meso-ferrocenyl groups on the conjugated macrocycle and the central metal ion of the ferrocenylcorrole derivatives. PMID:26460880

  2. β-Nitro-5,10,15-tritolylcorroles

    PubMed Central

    Stefanelli, Manuela; Pomarico, Giuseppe; Tortora, Luca; Nardis, Sara; Fronczek, Frank R.; McCandless, Gregory T.; Smith, Kevin M.; Manowong, Machima; Chen, Ping; Kadish, Karl M.; Rosa, Angela; Ricciardi, Giampaolo; Paolesse, Roberto

    2012-01-01

    Functionalization of the β-pyrrolic positions of the corrole macrocycle with –NO2 groups is limited at present to metallocorrolates due to of the instability exhibited by corrole free bases under oxidizing conditions. A careful choice of the oxidant can limit the transformation of corroles into decomposition products or isocorrole species, preserving the corrole aromaticity, and thus allowing the insertion of nitro groups onto the corrole framework. Here we report results obtained by reacting 5,10,15-tritolylcorrole (TTCorrH3) with the AgNO2/NaNO2 system, to give mono- and di-nitrocorrole derivatives when stoichiometry is carefully controlled. Reactions were found to be regioselective, affording the 3-NO2TTCorrH3 and 3,17-(NO2)2TTCorrH3 isomers as the main products in the case of mono- and di-substitution, in 53 and 20% yields, respectively. In both cases, traces of other mono- and di-substituted isomers were detected, which were structurally characterized by X-ray crystallography. The influence of the β-nitro substituents on the corrole properties is studied in detail by UV-visible, electrochemical, and spectroelectrochemical characterization of these functionalized corroles. Density Functional Theory (DFT) and time-dependent DFT (TDDFT) calculations of the ground and excited state properties of these β-nitrocorrole derivatives also afforded significant information, closely matching the experimental observations. It is found that the β-NO2 substituents conjugate with the π-aromatic system of the macrocycle, which initiates significant changes in both the spectroscopic and redox properties of the so functionalized corroles. This effect is more pronounced when the nitro group is introduced at the 2-position, because in this case the conjugation is, for steric reasons, more efficient than in the 3-nitro isomer. PMID:22668242

  3. The corrole and ferrocene marriage: 5,10,15-triferrocenylcorrolato Cu.

    PubMed

    Pomarico, Giuseppe; Vecchi, Andrea; Mandoj, Federica; Bortolini, Olga; Cicero, Daniel O; Galloni, Pierluca; Paolesse, Roberto

    2014-04-21

    Two synthetic routes have been defined for the preparation of a 5,10,15-triferrocenylcorrole Cu derivative. This complex has been characterized and the preliminary electrochemical investigation shows a strong interaction among the corrole and meso ferrocenyl substituents. The results obtained suggest that peculiar properties are gained by combining the eccentric characteristics of ferrocenyl substitution with the corrole macrocycle. PMID:24616907

  4. Interaction peculiarities of 5,10,15,20-tetrakis(4-N-methylpyridil) tetra iodide porphyrin with albumin

    NASA Astrophysics Data System (ADS)

    Lebedeva, N. Sh.; Malkova, E. A.; Popova, T. E.; Kutyrev, A. E.; Syrbu, S. A.; Parfenyuk, E. V.; Vyugin, A. I.

    2014-01-01

    In present work interactions of bovine serum albumin with 5,10,15,20-tetrakis(4-N-methylpyridil) tetra iodide porphyrin have been studied by electron absorption and fluorescence spectroscopy. The studies were carried out in aqueous media at different pH and in water-dimethylformamide mixtures containing up to 0.19 M of the organic solvent. It has been demonstrated that the porphyrin forms stable complexes with BSA in which the porphyrin is located subdomains IB and IIA. The stability constants of the complexes is practically independent of pH.

  5. Method of using 5,10,15,20-tetrakis(carboxyphenyl)porphine for detecting cancers of the lung

    DOEpatents

    Cole, D.A.; Moody, D.C. III; Ellinwood, L.E.; Klein, M.G.

    1992-11-10

    A method is described for using tetra-aryl porphyrins for and, in particular, 5,10,15,20-tetrakis(4-carboxyphenyl)porphine as a fluorescent tracer for cancers of the lung, and as a radiotracer therefor as a complex with [sup 67]Cu. The latter complex also provides a source of beta radiation for selective destruction of lung malignancies as well as gamma radiation useful for image analysis of the lungs by single photon emission computed tomography, as an example, both in vivo. Copper-64 may be substituted for the [sup 67]Cu if only radiotracer characteristics are of interest. This lighter isotope of copper is a positron emitter, and positron emission tomography techniques can be used to locate the malignant tissue mass. 1 figure.

  6. Method of using 5,10,15,20-tetrakis(carboxyphenyl)porphine for detecting cancers of the lung

    DOEpatents

    Cole, Dean A.; Moody, III, David C.; Ellinwood, L. Edward; Klein, M. Gerard

    1992-01-01

    Method using tetra-aryl porphyrins for and, in particular, 5,10,15,20-tetrakis(4-carboxyphenyl)porphine as a fluorescent tracer for cancers of the lung, and as a radiotracer therefor as a complex with .sup.67 Cu. The latter complex also provides a source of beta radiation for selective destruction of lung malignancies as well as gamma radiation useful for image analysis of the situs thereof by single photon emission computed tomography, as an example, both in vivo. Copper-64 may be substituted for the .sup.67 Cu if only radiotracer characteristics are of interest. This lighter isotope of copper is a positron emitter, and positron emission tomography techniques cna be used to locate the malignant tissue mass.

  7. Method using 5,10,15,20-tetrakis(4-carboxyphenyl)porphine for treating cancers of the lung

    DOEpatents

    Cole, Dean A.; Moody, III, David C.; Ellinwood, L. Edward; Klein, M. Gerard

    1995-01-01

    Method using tetra-aryl porphyrins for and, in particular, 5,10,15,20-tetrakis(4-carboxyphenyl)porphine as a fluorescent tracer for cancers of the lung, and as a radiotracer therefor as a complex with .sup.67 Cu. The latter complex also provides a source of beta radiation for selective destruction of lung malignancies as well as gamma radiation useful for image analysis of the situs thereof by single photon emission computed tomography, as an example, both in vivo. Copper-64 may be substituted for the .sup.67 Cu if only radiotracer characteristics are of interest. This lighter isotope of copper is a positron emitter, and positron emission tomography techniques can be used to locate the malignant tissue mass.

  8. In vitro cytotoxicity assessment of [5,10,15,20-tetra (4-sulfophenyl) porphyrin] on tumor and nontumor cell lines

    NASA Astrophysics Data System (ADS)

    Alexandrova, R.; Sabotinov, O.; Stoykova, Elena V.; Ion, Rodica-Mariana; Shurulinkov, Stanislav; Minchev, Georgi

    2004-06-01

    In this study we evaluate the cytotoxicity of 5,10,15,20- tetra (4-sulfophenyl) porphyrins on a tumor cell line LSCC-SF-Mc29, obtained from a transplantable chicken hepatoma induced by the myelocytomatosis virus Mc29, a timor line LSR-SF-SR, obtained from a transplantable sarcoma in rat induced by Rous sarcoma virus strain Schmidt-Ruppin and for normal mouse cell line (BALB/c-3T3-A31) and bovine kidney cell line (MDBK). The cells were exposed to irradiation from a pulsed CuBr vapor laser system at 510.6 nm and 578.2 nm at fluence rate 50 mW/cm2 and pulse frequency rate 20 kHz. The viability of cells was determined by the neutral red uptake cytotoxicity assay. The light dose-response curves and light exposures that ensure viability drop to 50 % were obtained for each cell line. The cytotoxic effect of TS4PP is most distinguished for LSCC-SF-Mc29. The bovine cell line is more vulnerable than the mouse line, especially at 510.6 nm. The 2-4 times higher viability of the normal cell lines in comparison with the tumor lines has been obtained.

  9. Synthesis and properties of 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl] chlorin as potential broad-spectrum antimicrobial photosensitizers.

    PubMed

    Ferreyra, Darío D; Reynoso, Eugenia; Cordero, Paula; Spesia, Mariana B; Alvarez, M Gabriela; Milanesio, M Elisa; Durantini, Edgardo N

    2016-05-01

    A novel 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]chlorin (TAPC) was synthesized by reduction of the corresponding porphyrin TAPP with p-toluenesulfonhydrazide, followed by selective oxidation with o-chloranil. Spectroscopic properties and the photodynamic activity of these photosensitizers were compared in N,N-dimethylformamide. An increase in the absorption band at 650nm was found for the chlorin derivative with respect to TAPP. These photosensitizers emit red fluorescence with quantum yields of 0.15. Both compounds were able to photosensitize singlet molecular oxygen with quantum yields of about 0.5. Also, the formation of superoxide anion radical was detected in the presence of TAPC or TAPP and NADH. Photodynamic inactivation was investigated on a Gram-positive bacterium Staphylococcus aureus, a Gram-negative bacterium Escherichia coli and a fungal yeast Candida albicans cells. In vitro experiments showed that TAPC or TAPP were rapidly bound to microbial cells at short incubation periods. These photosensitizers, without intrinsic positive charges, contain four basic amino groups. These substituents can be protonated at physiological pH, increasing the interaction with the cell envelopment. Photosensitized inactivation improved with an increase of both photosensitizer concentrations and irradiation times. After 15min irradiation, a 7 log reduction of S. aureus was found for treated with 1μM photosensitizer. Similar result was obtained with E. coli after using 5μM photosensitizer and 30min irradiation. Also, the last conditions produced a decrease of 5 log in C. albicans cells. Therefore, TAPC was highly effective as a broad-spectrum antimicrobial photosensitizer. PMID:26994333

  10. Synthesis and unusual properties of the first 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraalkylporphyrin

    SciTech Connect

    NELSON,NORA Y.; MEDFORTH,CRAIG J.; NURCO,DANIEL J.; JIA,SONG-LING; SHELNUTT,JOHN A.; SMITH,KEVIN M.

    2000-03-06

    The new perhalogenated porphyrin 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(trifluoromethyl)porphinato-nickel(II) exhibits several striking features, including an extremely ruffled macrocycle with a very short Ni-N distance, an unusually red-shifted optical spectrum, and, surprisingly, hindered rotation of the meso-trifluoromethyl substituents ({Delta}G{sub 278}{sup +} = 47 kJ/mol).

  11. Early lung cancer detection project: Evaluation of 5, 10, 15, 20 tetrakis (4-carboxyphenyl) porphine (H{sub 2}TCPP). Final report

    SciTech Connect

    Tockman, M.S.

    1998-10-01

    The author evaluated a synthetic porphyrin, 5, 10, 15, 20 tetrakis (4-carboxyphenyl) porphene (H{sub 2}TCPP) as a marker of carcinogenesis. H{sub 2}TCPP was compared with two other carcinogenesis markers evaluated in the laboratory for their ability to detect exfoliated sputum cells undergoing transformation to lung cancer. In the present project the authors first established optimal conditions for cultured neoplastic and non-neoplastic (sputum) cells to take up H{sub 2}TCPP. This was accomplished using spectrofluorimetry and video-enhanced fluorescent microscopy to maximize H{sub 2}TCPP auto-fluorescence across a matrix of substrate conditions, including; reagent concentration, incubation time, temperature, and pH. The second aim was to validate H{sub 2}TCPP on clinical material obtained from subjects monitored in advance of clinical cancer and link those marker results with subsequent histologic confirmation of disease. This was accomplished by applying H{sub 2}TCPP to sputum specimens archived by the Frost Center at Johns Hopkins which maintains a record of the clinical course and long-term follow-up for the patients from whom the specimens were obtained. The authors have used fluorescent immunostaining and flow cytometry to compare uptake of these cytoplasmic Mabs to that of a potential new marker of carcinogenesis, 5, 10, 15, 20 tetrakis (4 carboxyphenyl) porphene (H{sub 2}TCPP). The nuclear uptake of H{sub 2}TCPP was compared to a standard quantitative fluorescent DNA marker (7-AAD).

  12. Photophysical Characterization and in Vitro Phototoxicity Evaluation of 5,10,15,20-Tetra(quinolin-2-yl)porphyrin as a Potential Sensitizer for Photodynamic Therapy.

    PubMed

    Costa, Letícia D; e Silva, Joana de A; Fonseca, Sofia M; Arranja, Cláudia T; Urbano, Ana M; Sobral, Abilio J F N

    2016-01-01

    Photodynamic therapy (PDT) is a selective and minimally invasive therapeutic approach, involving the combination of a light-sensitive compound, called a photosensitizer (PS), visible light and molecular oxygen. The interaction of these per se harmless agents results in the production of reactive species. This triggers a series of cellular events that culminate in the selective destruction of cancer cells, inside which the photosensitizer preferentially accumulates. The search for ideal PDT photosensitizers has been a very active field of research, with a special focus on porphyrins and porphyrin-related macrocycle molecules. The present study describes the photophysical characterization and in vitro phototoxicity evaluation of 5,10,15,20-tetra(quinolin-2-yl)porphyrin (2-TQP) as a potential PDT photosensitizer. Molar absorption coefficients were determined from the corresponding absorption spectrum, the fluorescence quantum yield was calculated using 5,10,15,20-tetraphenylporphyrin (TPP) as a standard and the quantum yield of singlet oxygen generation was determined by direct phosphorescence measurements. Toxicity evaluations (in the presence and absence of irradiation) were performed against HT29 colorectal adenocarcinoma cancer cells. The results from this preliminary study show that the hydrophobic 2-TQP fulfills several critical requirements for a good PDT photosensitizer, namely a high quantum yield of singlet oxygen generation (Φ∆ 0.62), absence of dark toxicity and significant in vitro phototoxicity for concentrations in the micromolar range. PMID:27043519

  13. Effects of dietary glycerin inclusion at 0, 5, 10, and 15 percent of dry matter on energy metabolism and nutrient balance in finishing beef steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Expansion of the biodiesel industry has increased the glycerin (GLY) supply. Glycerin is an energy-dense feed that can be used in ruminant species; however, the energy value of GLY is not known. Therefore, the effects of GLY inclusion at 0%, 5%, 10%, and 15% on energy balance in finishing cattle d...

  14. Effects of dietary glycerin inclusion at 0, 5, 10, and 15% of dry matter on energy metabolism and nutrient balance in finishing beef steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Expansion of the biodiesel industry has increased the glycerin (GLY) supply. Glycerin is an energy-dense feed that can be used in ruminant species; however, the energy value of GLY is not known. Therefore, the effects of GLY inclusion at 0%, 5%, 10%, and 15% in dry-rolled corn (DRC)-based diets we...

  15. Novel nanomaterials based on 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-21H,23H-porphyrin entrapped in silica matrices

    SciTech Connect

    Fagadar-Cosma, Eugenia; Enache, Corina; Vlascici, Dana; Fagadar-Cosma, Gheorghe; Vasile, Mihaela; Bazylak, Grzegorz

    2009-12-15

    The present study is dealing with the obtaining of transparent hybrid silica materials encapsulating 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-21H,23H-porphyrin designated for advanced optoelectronic devices. The porphyrin was synthesized by three methods: an Adler-type reaction between pyrrole and 3,4-dimethoxybenzaldehyde in propionic acid medium; by Lindsey condensation of pyrrole with 3,4-dimethoxybenzaldehyde in the presence of BF{sub 3}.OEt{sub 2} and by a multicomponent reaction by simultaneously using of pyrrole and two different aldehydes: 3,4-dimethoxybenzaldehyde and 3-hydroxybenzaldehyde. The 3,4-dimethoxyphenyl substituted porphyrin was characterized by HPLC, TLC, UV-vis, FT-IR, {sup 1}H NMR and {sup 13}C NMR analysis. Excitation and emission spectra were also discussed in terms of pH conditions. The hybrid materials, consisting in the porphyrin encapsulated in silica matrices, have been prepared successfully via the two steps acid-base catalyzed hydrolysis and condensation of tetraethylorthosilicate using different approaches of the sol-gel process: in situ, by impregnation and by sonication. The synthetic conditions and the compositions were monitored and characterized by using spectroscopic methods such as FT-IR, fluorescence and UV-vis. Atomic force microscopy (AFM) has been applied to observe the columnar or pyramidal nanostructures which are formed by the immobilization of porphyrin on the silica matrices.

  16. A true electron-transfer reaction between 5,10,15,20-tetraphenylporphyrinato cadmium(II) and the hexacyanoferrate couple at the nitrobenzene/water interface.

    PubMed

    Osakai, Toshiyuki; Ichikawa, Seiko; Hotta, Hiroki; Nagatani, Hirohisa

    2004-11-01

    The ability of some metal complexes of 5,10,15,20-tetraphenylporphyrin (TPP) to give a voltammetric wave due to the heterogeneous electron transfer (ET) at a nitrobenzene (NB)/water (W) interface has been examined. The previously-proposed, electron-conductor separating oil-water (ECSOW) system has been successfully employed to find that the TPP complex with cadmium(II) added to NB gives a well-defined, reversible wave for the heterogeneous (i.e., "true") ET with the hexacyanoferrate couple in W. A digital simulation analysis has entirely excluded the possibility of the ion-transfer mechanism due to the homogeneous ET in W. The a.c. impedance method has then been used to determine the kinetic parameters including the standard rate constant k0 (= 0.10 cm M(-1) s(-1)) and the transfer coefficient alpha (= 0.53 at the half-wave potential). These values are in good agreement with those predicted from the Marcus theory with the assumption that the heterogeneous ET due to molecular collision occurs at the "sharp" NB/W interface. PMID:15566151

  17. Mössbauer effect study of tight spin coupling in oxidized chloro-5,10,15,20- tetra(mesityl)porphyrinatoiron(III)

    NASA Astrophysics Data System (ADS)

    Boso, Brian; Lang, George; McMurry, Thomas J.; Groves, John T.

    1983-08-01

    Mössbauer spectra of a polycrystalline form of oxidized chloro-5,10,15,20-tetra(mesityl)porphyrin- atoiron(III) [Fe(TMP)Cl], compound A, were recorded over a range of temperatures (4.2-195 K) and magnetic fields (0-6 T). These spectra of compound A exhibit magnetic features which are markedly different from those of the analogous protein complexes, horse radish peroxidase compound I (HRP-I) and compound ES of cytochrome c peroxidase, even though chemical evidence and optical spectroscopy indicate that compound A is similar to the others in comprising a Fe(IV) complex within a porphyrin cation radical. We interpret the data by employing a spin Hamiltonian model in which the central Fe(IV) complex, with S=1, is tightly coupled to a S=1/2 system of the oxidized porphyrin to yield a net S=3/2 system as suggested by the susceptibility measurements. The theoretical treatment yields information on the d-electron energies which is similar to that more directly available in the peroxidase spectra. The strength of the axial crystal field is found to increase progressively in the series HRP-I, ES, compound A, while the spin coupling in A is the strongest of the three by several orders of magnitude. The good fits to experimental data confirm the efficacy of the theoretical treatment which may be applicable to a variety of other coupled systems.

  18. Thermodynamics and kinetics of the formation of the supramolecular complexes bisacetato(5,10,15,20-tetraphenylporphinate)zirconium(IV) with pyridine and imidazole

    NASA Astrophysics Data System (ADS)

    Tyulyaeva, E. Yu.; Lomova, T. N.

    2010-05-01

    The equilibria and rates of step reactions for the formation of the supramolecular complexes of bisacetato(5,10,15,20-tetraphenylporphinate)zirconium(IV) (AcO)2ZrTPP and bioactive bases pyridine (Py) and imidazole (Im) in toluene were studied using UV-Vis and IR spectroscopy. The step stoichiometric mechanism, including the reversible coordination of two Py molecules ( K 1 = 1.8 × 108 l2/mol2), the equilibrium of the displacement of two AcO- into the second coordination sphere by increasing the concentration of the solvent polar component ( K 2 = 2.4), and the coordination of the third and fourth Py molecules in a one step with the formation of [(Py)4ZrTPP]2+ · 2(AcO)- ( K 3 = 2.8 × 104 l2/mol2), was verified. It was established that the spectrophotometric titration is sensible for the two-stage π-π-complexation of [(Py)4ZrTPP]2+ · 2(AcO)- with Py molecules ( K 4 = 29 l/mol and K 5 = 1.8 l/mol). It was shown that the stronger base Im reacts irreversibly with (AcO)2ZrTPP. The thermodynamic and optical characteristics of (AcO)2ZrTPP required for using the complex in the detection of bioactive bases were studied.

  19. A direct sensitized fluorimetric determination of 5,10,15,20-tetra(m-hydroxyphenyl)chlorin [m-THPC (Foscan)] in human plasma using a cyclodextrin inclusion complex.

    PubMed

    Desroches, M C; Kasselouri, A; Bourdon, O; Chaminade, P; Blais, J; Prognon, P

    2001-06-01

    The 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (m-THPC) (Foscan) is a photosensitizer used in the photodynamic therapy (PDT) of cancers which is currently under clinical trial. The formation of a m-THPC inclusion complex with dimethyl-beta-cyclodextrin (Me-beta-CD) in solution was demonstrated on the basis of circular dichroism experiments. A 1:2 complex stoichiometry was found and an inclusion constant beta 2 = 2.8(+/- 0.4) x 10(10) M-2 was determined. The formation of such a complex was shown to enhance the m-THPC fluorescence intensity. It could be exploited to improve the sensitivity of the direct m-THPC detection in human plasma. Optimization of the operating conditions shows that the best results were obtained by the addition of 100 microL of a concentrated Me-beta-CD solution (3.2 x 10(-2) M) to 1 mL plasma samples. Compared to the standard conditions, a 90% increase in sensitivity was obtained. The proposed analytical method which showed a linear response function [0-300 ng mL-1 (440 pM)] and a low limit of detection [1.5 ng mL-1 (2 pM) (S/N = 3)] appears, especially due to the absence of metabolism, a simple and specific method suitable for pharmacokinetics studies in patients. PMID:11445963

  20. Mitochondria and DNA Targeting of 5,10,15,20-Tetrakis(7-sulfonatobenzo[b]thiophene) Porphyrin-Induced Photodynamic Therapy via Intrinsic and Extrinsic Apoptotic Cell Death.

    PubMed

    Rangasamy, Sabarinathan; Ju, Hee; Um, Soohyun; Oh, Dong-Chan; Song, Joon Myong

    2015-09-10

    Photodynamic therapy (PDT) selectively targets subcellular organelles and promises an excellent therapeutic strategy for cancer treatment. Here, we report the synthesis of a new water-soluble photosensitizer, 5,10,15,20-tetrakis (7-sulfonatobenzo[b]thiophene) porphyrin (SBTP). Rational design of the porphyrinic molecule containing benzo[b]thiophene moiety at the meso-position led to selective accumulation in both mitochondria and nucleus of MCF-7 cells. This multitarget ability of SBTP can cause damage to mitochondria as well as DNA simultaneously. FACS analysis showed rapid cellular uptake of SBTP. High-content cell-based assay was executed to concurrently monitor increase of cytosolic Ca(2+) levels, mitochondrial permeability transition (MPT), and caspase-3/7/8 activation in MCF-7 cells under the pathological condition caused by PDT action of SBTP. The study of cell death dynamics showed that PDT action of SBTP caused an increase in the MPT followed by an increase in cytosolic Ca(2+) level. The localization of SBTP in the mitochondria activated the intrinsic apoptotic pathway. Additionally, localization of SBTP in the nucleus led to DNA damage in MCF-7 cells. The DNA fragmentation that occurred by PDT action of SBTP was thought to be responsible for extrinsic apoptosis of MCF-7 cells. SBTP demonstrated effective PDT activity of 5 μM IC50 value to MCF-7 cells by bitargeting mitochondria and DNA. PMID:26295496

  1. Structural, optical and dispersion properties of 5,10,15,20-tetraphenyl-21H,23H-porphyrin zinc thin films

    NASA Astrophysics Data System (ADS)

    Zeyada, Hamdy M.; Makhlouf, Mohamed M.; Ali, Mohamed A.

    2016-02-01

    The thin films of 5,10,15,20-tetraphenyl-21H,23H-porphyrin zinc, ZnTPP, were successfully prepared by the thermal evaporation technique. The structure formation and optical properties of ZnTPP thin films were studied. The surface morphology and structural characteristics of ZnTPP thin films were analyzed by atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques, respectively. The optical constants of ZnTPP films were measured by spectrophotometer measurements of the transmittance and reflectance at a normal incidence of light in the spectral wavelength range from 200 to 2500 nm. The absorption spectrum of ZnTPP films showed four absorption bands, namely, the Q, B, N, and M bands. Anomalous dispersion was observed in the absorption region and normal dispersion occurred in the transparent region of the spectrum. We adopted the multi-oscillator and the single-oscillator models to interpret the results of anomalous and normal dispersion characteristics, respectively. The energy band gap of ZnTPP films was measured and the type of electron transition was determined to be the indirect allowed transition. The annealing process had an obvious effect on the morphology, structure, optical constants, and spectral dispersion parameters of ZnTPP thin films.

  2. 21 CFR 73.3117 - 16,23-Dihydrodinaphtho[2,3-a:2′,3′-i] naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3117 16,23-Dihydrodinaphtho naphth indolo carbazole-5,10,15,17,22,24-hexone. (a)...

  3. 21 CFR 73.3117 - 16,23-Dihydrodinaphtho[2,3-a:2′,3′-i] naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3117 16,23-Dihydrodinaphtho naphth indolo carbazole-5,10,15,17,22,24-hexone. (a)...

  4. NiO nanoparticles modified with 5,10,15,20-tetrakis(4-carboxyl pheyl)-porphyrin: promising peroxidase mimetics for H2O2 and glucose detection.

    PubMed

    Liu, Qingyun; Yang, Yanting; Li, Hui; Zhu, Renren; Shao, Qian; Yang, Shanguang; Xu, Jingjing

    2015-02-15

    NiO nanoparticles (NPs) and 5,10,15,20-tetrakis(4-carboxyl pheyl)-porphyrin (H2TCPP) functionalized NiO nanoparticles (H2TCPP-NiO nanocomposites) have been prepared by a facile method and characterized by powder X-ray diffraction (XRD), transmission electron microscope (TEM) and Fourier transform infrared spectra (FTIR), respectively. NiO NPs and H2TCPP-NiO nanocomposites have been proven to function as peroxidase mimetics that can catalyze the reaction of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue color reaction. Kinetic analysis indicated that the catalytic behavior was in accord with typical Michaelis-Menten kinetics. And these nanoparticles also exhibited strong affinity for the substrates of 3,3,5,5-tetramethylbiphenyl dihydrochloride (TMB). Experimental results showed that H2TCPP-NiO NPs exhibited a high sensitivity and a low detection limit towards H2O2 (8.0 × 10(-6) M). The H2TCPP-NiO NPs/glucose oxidase (GOx)/TMB system provides a novel colorimetric sensor for glucose and shows good response toward glucose detection over arrange of 0.05-0.50 mM with a limit of detection 2.0 × 10(-5)M. Fluorescence probe experiments demonstrated that the peroxidase-like activity of H2TCPP-NiO NPs originated from the generation of OH radical. Thus it may provide great potential applications in biomedicine, biotechnology and environmental chemistry. PMID:25212068

  5. Manganese [III] Tetrakis [5,10,15,20]-Benzoic Acid Porphyrin Reduces Adiposity and Improves Insulin Action in Mice with Pre-Existing Obesity

    PubMed Central

    Brestoff, Jonathan R.; Brodsky, Tim; Sosinsky, Alexandra Z.; McLoughlin, Ryan; Stansky, Elena; Fussell, Leila; Sheppard, Aaron; DiSanto-Rose, Maria; Kershaw, Erin E.; Reynolds, Thomas H.

    2015-01-01

    The superoxide dismutase mimetic manganese [III] tetrakis [5,10,15,20]-benzoic acid porphyrin (MnTBAP) is a potent antioxidant compound that has been shown to limit weight gain during short-term high fat feeding without preventing insulin resistance. However, whether MnTBAP has therapeutic potential to treat pre-existing obesity and insulin resistance remains unknown. To investigate this, mice were treated with MnTBAP or vehicle during the last five weeks of a 24-week high fat diet (HFD) regimen. MnTBAP treatment significantly decreased body weight and reduced white adipose tissue (WAT) mass in mice fed a HFD and a low fat diet (LFD). The reduction in adiposity was associated with decreased caloric intake without significantly altering energy expenditure, indicating that MnTBAP decreases adiposity in part by modulating energy balance. MnTBAP treatment also improved insulin action in HFD-fed mice, a physiologic response that was associated with increased protein kinase B (PKB) phosphorylation and expression in muscle and WAT. Since MnTBAP is a metalloporphyrin molecule, we hypothesized that its ability to promote weight loss and improve insulin sensitivity was regulated by heme oxygenase-1 (HO-1), in a similar fashion as cobalt protoporphyrins. Despite MnTBAP treatment increasing HO-1 expression, administration of the potent HO-1 inhibitor tin mesoporphyrin (SnMP) did not block the ability of MnTBAP to alter caloric intake, adiposity, or insulin action, suggesting that MnTBAP influences these metabolic processes independent of HO-1. These data demonstrate that MnTBAP can ameliorate pre-existing obesity and improve insulin action by reducing caloric intake and increasing PKB phosphorylation and expression. PMID:26397111

  6. Manganese [III] Tetrakis [5,10,15,20]-Benzoic Acid Porphyrin Reduces Adiposity and Improves Insulin Action in Mice with Pre-Existing Obesity.

    PubMed

    Brestoff, Jonathan R; Brodsky, Tim; Sosinsky, Alexandra Z; McLoughlin, Ryan; Stansky, Elena; Fussell, Leila; Sheppard, Aaron; DiSanto-Rose, Maria; Kershaw, Erin E; Reynolds, Thomas H

    2015-01-01

    The superoxide dismutase mimetic manganese [III] tetrakis [5,10,15,20]-benzoic acid porphyrin (MnTBAP) is a potent antioxidant compound that has been shown to limit weight gain during short-term high fat feeding without preventing insulin resistance. However, whether MnTBAP has therapeutic potential to treat pre-existing obesity and insulin resistance remains unknown. To investigate this, mice were treated with MnTBAP or vehicle during the last five weeks of a 24-week high fat diet (HFD) regimen. MnTBAP treatment significantly decreased body weight and reduced white adipose tissue (WAT) mass in mice fed a HFD and a low fat diet (LFD). The reduction in adiposity was associated with decreased caloric intake without significantly altering energy expenditure, indicating that MnTBAP decreases adiposity in part by modulating energy balance. MnTBAP treatment also improved insulin action in HFD-fed mice, a physiologic response that was associated with increased protein kinase B (PKB) phosphorylation and expression in muscle and WAT. Since MnTBAP is a metalloporphyrin molecule, we hypothesized that its ability to promote weight loss and improve insulin sensitivity was regulated by heme oxygenase-1 (HO-1), in a similar fashion as cobalt protoporphyrins. Despite MnTBAP treatment increasing HO-1 expression, administration of the potent HO-1 inhibitor tin mesoporphyrin (SnMP) did not block the ability of MnTBAP to alter caloric intake, adiposity, or insulin action, suggesting that MnTBAP influences these metabolic processes independent of HO-1. These data demonstrate that MnTBAP can ameliorate pre-existing obesity and improve insulin action by reducing caloric intake and increasing PKB phosphorylation and expression. PMID:26397111

  7. Application of an octa-anionic 5,10,15,20-tetra[3,5-(nido-carboranylmethyl)phenyl]porphyrin (H2OCP) as dual sensitizer for BNCT and PDT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The applications of the octa-anionic 5,10,15,20-tetra[3,5-(nidocarboranylmethyl) phenyl]porphyrin (H2OCP) as a boron delivery agent in boron neutron capture therapy (BNCT) and a photosensitizer in photodynamic therapy (PDT) have been investigated. Using F98 Rat glioma cells, we evaluated the cytotox...

  8. Transient formation of the oxo-iron(IV) porphyrin radical cation during the reaction of iron(III) tetrakis-5,10,15,20-(N-methyl-4-pyridyl)porphyrin with hydrogen peroxide in aqueous solution.

    PubMed

    Saha, Tapan Kumar; Karmaker, Subarna; Tamagake, Keietsu

    2003-01-01

    The reaction of iron(III) tetrakis-5,10,15,20-(N-methyl-4-pyridyl)porphyrin (Fe(III)TMPyP) with hydrogen peroxide (H(2)O(2)) and the catalytic activity of the reaction intermediates on the luminescent peroxidation of luminol in aqueous solution were studied by using a double-mixing stopped-flow system. The observed luminescence intensities showed biphasic decay depending on the conditions. The initial flashlight decayed within <1 s followed by a sustained emission for more than 30 s. Computer deconvolution of the time-resolved absorption spectra under the same conditions revealed that the initial flashlight appeared during the formation of the oxo-iron(IV) porphyrin, TMPyPFe(IV) = O, which is responsible for the sustained emission. The absorption spectra 0.0-0.5 s did not reproduce well by a simple combination of the two spectra of Fe(III)TMPyP and TMPyPFe(IV) = O, indicating that transient species was formed at the initial stage. Addition of uric acid (UA) caused a significant delay in the initiation of the luminol emission as well as in the formation of the TMPyPFe(IV) = O. Both of them were completely diminished in the presence of UA equimolar with H(2)O(2), while mannitol had no effect at all. The delay of the light emission as well as the appearance of TMPyPFe(IV) = O was directly proportional to the [UA](0) but other kinetic profiles were not changed significantly. Based on these observations and the kinetic analysis, we confirmed the involvement of the oxo-iron(IV) porphyrin radical cation, (TMPyP)(.+)Fe(IV) = O, as an obligatory intermediate in the rate-determining step of the overall reaction, Fe(III)TMPyP + H(2)O(2) --> TMPyPFe(IV) = O, with a rate constant of k = 4.3 x 10(4)/mol/L/s. The rate constants for the reaction between the (TMPyP)(.+)Fe(IV) = O and luminol, and between the TMPyPFe(IV) = O and luminol were estimated to be 3.6 x 10(6)/mol/L/s and 1.31 x 10(4)/mol/L/s, respectively. PMID:12701092

  9. Synthesis, structure, electronic spectroscopy, photophysics, electrochemistry, and X-ray photoelectron spectroscopy of highly-electron-deficient [5,10,15,20-tetrakis(perfluoroalkyl)porphinato]zinc(II ) complexes and their free base derivatives

    SciTech Connect

    Goll, J.G.; Moore, K.T.; Therien, M.J.; Ghosh, A.

    1996-09-04

    The synthesis, optical spectroscopy, photophysical properties, electrochemistry, and X-ray photoelectron spectroscopy of a series of [5,10,15,20-tetrakis(perfluoroalkyl)porphinato]zinc(II ) complexes and their free base analogs are reported. The title compounds were prepared by a condensation methodology that utilizes perfluoro-1-(2`-pyrrolyl)-1-alkanol precursors and employs continuous water removal throughout the course of the reaction to yield the meso perfluorocarbon-substituted porphyrins. The nature of the porphyrin-pendant meso-perfluoroalkyl group exerts considerable influence over the macrocycle`s solubility properties. The structure of the monopyridyl adduct of [5,10,15,20-tetrakis(heptafluoropropyl)porphinato] zinc(II) features an S{sub 4}-distorted porphyrin core; X-ray data are given. Electrochemical studies carried out on these porphyrin and (porphinato)zinc(II) complexes indicate that meso-perfluoroalkylporphyrins are among the most electron-deficient porphyrinic species known. X-ray photoelectron spectroscopy experiments corroborate the electron poor nature of these systems and evince extreme stabilization of the nitrogen ls orbitals, consonant with particularly effective removal of electron density from the macrocycle by the meso-perfluoroalkyl moieties that is modulated by {sigma}-symmetry orbitals. 27 refs., 8 figs., 6 tabs.

  10. Crystal structure of di­aqua­[5,10,15,20-tetra­kis­(4-bromo­phen­yl)porphyrinato-κ4 N]magnesium

    PubMed Central

    Amiri, Nesrine; Nasri, Soumaya; Roisnel, Thierry; Simonneaux, Gérard; Nasri, Habib

    2015-01-01

    The title compound, [Mg(C44H24Br4N4)(H2O)2] or [Mg(TBrPP)(H2O)2], where TBrPP is the 5,10,15,20-tetra­kis­(4-bromo­phen­yl)porphyrinato ligand, was obtained unintentionally as a by-product of the reaction of the [Mg(TBrPP)] complex with an excess of di­methyl­glyoxime in di­chloro­methane. The entire mol­ecule exhibits point group symmetry 4/m. In the asymmetric unit, except for two C atoms of the phenyl ring, all other atoms lie on special positions. The MgII atom is situated at a site with symmetry 4/m, while the N and the C atoms of the porphyrin macrocycle, as well as two C atoms of the phenyl ring and the Br atom lie in the mirror plane containing the porphyrin core. The H atoms of the axially bonded water mol­ecule are incompatible with the fourfold rotation axis and are disordered over two sites. In the crystal, mol­ecules are packed in rows along [001]. Weak inter­molecular C—H⋯π and C—H⋯Br inter­actions, as well as O—H⋯Br hydrogen bonds, stabilize the crystal packing. PMID:25844215

  11. Synthesis, FT-IR characterization and crystal structure of aqua-(5,10,15,20-tetra-phenyl-porphyrinato-κ(4) N)manganese(III) tri-fluoro-methane-sulfonate.

    PubMed

    Harhouri, Wafa; Mchiri, Chadlia; Najmudin, Shabir; Bonifácio, Cecilia; Nasri, Habib

    2016-05-01

    In the title salt, [Mn(C44H28N4)(H2O)](CF3SO3) or [Mn(III)(TPP)(H2O)](CF3SO3) (where TPP is the dianion of 5,10,15,20-tetra-phenyl-porphyrin), the Mn(III) cation is chelated by the four pyrrole N atoms of the porphyrinate anion and additionally coordinated by an aqua ligand in an apical site, completing the distorted square-pyramidal coordination environment. The average Mn-N(pyrrole) bond length is 1.998 (9) Å and the Mn-O(aqua) bond length is 2.1057 (15) Å. The central Mn(III) ion is displaced by 0.1575 (5) Å from the N4C20 mean plane of the porphyrinate anion towards the apical aqua ligand. The porphyrinate macrocycle exhibits a moderate ruffling and strong saddle deformations. In the crystal lattice, the [Mn(III)(TPP)(H2O)](+) cation and the tri-fluoro-methane-sulfonate counter-ions are arranged in alternating planes packed along [001]. The components are linked together through O-H⋯O hydrogen bonds and much weaker C-H⋯O and C-H⋯F inter-actions. The crystal packing is further stabilized by weak C-H⋯π inter-actions involving the pyrrole and phenyl rings of the porphyrin moieties. PMID:27308027

  12. Reversible thermally induced phase transition in ordered domains of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin on Cu(111)

    NASA Astrophysics Data System (ADS)

    Stark, Michael; Ditze, Stefanie; Thomann, Michael; Lungerich, Dominik; Jux, Norbert; Steinrück, Hans-Peter; Marbach, Hubertus

    2016-08-01

    We investigated the adsorption behavior of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin (CoTTBPP) on Cu(111) by scanning tunneling microscopy (STM). At room temperature (RT), the coverage dependent adsorption behavior follows an expected scheme: at low coverage step decoration is found, which evolves into supramolecular domains with a hexagonal order at higher coverage. Interestingly, upon cooling the sample to 180 K the occurrence of a clearly distinguishable coexisting herringbone phase is observed. Upon heating to RT again, the herringbone phase vanishes. Thus a temperature dependent, fully reversible phase transition was observed. High resolution STM micrographs allow for the determination of the intramolecular conformations which are different for the two supramolecular arrangements. In addition, we studied the bias voltage dependent appearance of the molecule in STM and assigned a dominant contribution of the central Co at negative bias voltages close to the Fermi edge to the occupied dz2 orbital. Interestingly, the herringbone phase, which dominates at 180 K, exhibits a significantly higher molecular density than the monomodal hexagonal arrangement at RT, which is in line with the "normal" behavior of freezing substances.

  13. A method for the detection of alcohol vapours based on optical sensing of magnesium 5,10,15,20-tetraphenyl porphyrin thin film by an optical spectrometer and principal component analysis.

    PubMed

    Kladsomboon, Sumana; Kerdcharoen, Teerakiat

    2012-12-13

    In this work we have proposed a method for the detection of alcohol vapours, i.e. methanol, ethanol and isopropanol, based on the optical sensing response of magnesium 5,10,15,20-tetraphenyl porphyrin (MgTPP) thin films, as measured by optical spectrometry with the assistance of chemometric analysis. We have implemented a scheme which allows a laboratory UV-vis spectrometer to act as a so-called "electronic nose" with very little modification. MgTPP thin films were prepared by a spin coating technique, using chloroform as the solvent, and then subjected to thermal annealing at 280°C in an argon atmosphere. These MgTPP optical gas sensors presented significant responses with methanol compared to ethanol and isopropanol, based on the dynamic flow of alcohol vapours at the same mol% of alcohol concentration. Density functional theory (DFT) calculations were performed to model the underlying mechanism of this selectivity. The performance of the optical gas sensors was optimised by varying the fabrication parameters. It is hoped that the MgTPP thin film together with an off-the-shelf optical spectrometer and a simple chemometrics algorithm can be a valuable tool for the analysis of alcoholic content in the beverage industry. PMID:23206399

  14. Crystal structure of bis-(benzyl-amine-κN)[5,10,15,20-tetra-kis-(4-chloro-phen-yl)porphyrinato-κ(4) N]iron(II) n-hexane monosolvate.

    PubMed

    Dhifaoui, Selma; Harhouri, Wafa; Bujacz, Anna; Nasri, Habib

    2016-01-01

    In the title compound, [Fe(II)(C44H24Cl4N4)(C6H5CH2NH2)2]·C6H14 or [Fe(II)(TPP-Cl)(BzNH2)2]·n-hexane [where TPP-Cl and BzNH2 are 5,10,15,20-tetra-kis-(4-chloro-phen-yl)porphyrinate and benzyl-amine ligands, respectively], the Fe(II) cation lies on an inversion centre and is octa-hedrally coordinated by the four pyrrole N atoms of the porphyrin ligand in the equatorial plane and by two amine N atoms of the benzyl-amine ligand in the axial sites. The crystal structure also contains one inversion-symmetric n-hexane solvent mol-ecule per complex mol-ecule. The average Fe-Npyrrole bond length [1.994 (3) Å] indicates a low-spin complex. The crystal packing is sustained by N-H⋯Cl and C-H⋯Cl hydrogen-bonding inter-actions and by C-H⋯π inter-molecular inter-actions, leading to a three-dimensional network structure. PMID:26870596

  15. Crystal structure of bis­(benzyl­amine-κN)[5,10,15,20-tetra­kis­(4-chloro­phen­yl)porphyrinato-κ4 N]iron(II) n-hexane monosolvate

    PubMed Central

    Dhifaoui, Selma; Harhouri, Wafa; Bujacz, Anna; Nasri, Habib

    2016-01-01

    In the title compound, [FeII(C44H24Cl4N4)(C6H5CH2NH2)2]·C6H14 or [FeII(TPP-Cl)(BzNH2)2]·n-hexane [where TPP-Cl and BzNH2 are 5,10,15,20-tetra­kis­(4-chloro­phen­yl)porphyrinate and benzyl­amine ligands, respectively], the FeII cation lies on an inversion centre and is octa­hedrally coordinated by the four pyrrole N atoms of the porphyrin ligand in the equatorial plane and by two amine N atoms of the benzyl­amine ligand in the axial sites. The crystal structure also contains one inversion-symmetric n-hexane solvent mol­ecule per complex mol­ecule. The average Fe—Npyrrole bond length [1.994 (3) Å] indicates a low-spin complex. The crystal packing is sustained by N—H⋯Cl and C—H⋯Cl hydrogen-bonding inter­actions and by C—H⋯π inter­molecular inter­actions, leading to a three-dimensional network structure. PMID:26870596

  16. Crystal structure of chlorido­{5,10,15,20-tetra­kis­[2-(2,2-di­methyl­propanamido)­phen­yl]porphyrinato-κ4 N}iron(III)

    PubMed Central

    Awasabisah, Dennis; Powell, Douglas R.; Richter-Addo, George B.

    2015-01-01

    The title compound, [Fe(C64H64N8O4)Cl], is a five-coordinate square-pyramidal porphyrin complex with a chloride ion in the axial position, being coordinated from the protected side of the porphyrin; the FeIII atom is displaced by 0.474 (5) Å from the 24-atom mean plane of the porphyrin core towards the chloride. The porphyrin moiety is a ‘picket-fence’ 5,10,15,20-tetra­kis­[2-(2,2-di­methyl­propanamido)­phen­yl]porph­yrinate (por) group. The Fe—Cl bond length is 2.221 (2) Å and the Fe—N(por) bond lengths are in the range 2.043 (5)–2.063 (5) Å. The supra­molecular architecture of the crystal is sustained by C—H⋯O inter­actions between the pyrrolic and phenyl H atoms of one mol­ecule and the carbonyl O atoms of the 2,2-di­methyl­propanamido groups of adjacent mol­ecules. The methyl groups of three of the four tert-butyl substituents exhibited rotational disorder over two positions. The investigated crystal was twinned by a twofold rotation about the (001) axis with a refined twin ratio of 0.4086 (16). PMID:25878847

  17. Redetermination of cyclo-tetra­kis­(μ-5,10,15,20-tetra-4-pyridyl­porphyrinato)tetra­zinc(II) dimethyl­formamide octa­solvate trihydrate at 100 K

    PubMed Central

    Seidel, Rüdiger W.; Graf, Jürgen; Goddard, Richard; Oppel, Iris M.

    2011-01-01

    The structure of the title compound, [Zn4(C40H24N8)4]·8C3H7NO·3H2O, has been redetermined at 100 K. The redetermination is of significantly higher precision and gives further insight into the disorder of pyridyl groups and solvent mol­ecules. The mol­ecules of (5,10,15,20-tetra-4-pyridyl­porphyrinato)zinc(II) (ZnTPyP) form homomolecular cyclic tetra­mers by coordination of a peripheral pyridyl group to the central Zn atom of an adjacent symmetry-related mol­ecule. The tetra­mer so formed exhibits mol­ecular S 4 symmetry and is located about a crystallographic fourfold rotoinversion axis. Severely disordered dimethyl­formamide and water mol­ecules are present in the crystal, the contributions of which were omitted from refinement. Inter­molecular C—H⋯N hydrogen bonding is observed. PMID:21522892

  18. Synthesis, FT–IR characterization and crystal structure of aqua­(5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)manganese(III) tri­fluoro­methane­sulfonate

    PubMed Central

    Harhouri, Wafa; Mchiri, Chadlia; Najmudin, Shabir; Bonifácio, Cecilia; Nasri, Habib

    2016-01-01

    In the title salt, [Mn(C44H28N4)(H2O)](CF3SO3) or [MnIII(TPP)(H2O)](CF3SO3) (where TPP is the dianion of 5,10,15,20-tetra­phenyl­porphyrin), the MnIII cation is chelated by the four pyrrole N atoms of the porphyrinate anion and additionally coordinated by an aqua ligand in an apical site, completing the distorted square-pyramidal coordination environment. The average Mn—N(pyrrole) bond length is 1.998 (9) Å and the Mn—O(aqua) bond length is 2.1057 (15) Å. The central MnIII ion is displaced by 0.1575 (5) Å from the N4C20 mean plane of the porphyrinate anion towards the apical aqua ligand. The porphyrinate macrocycle exhibits a moderate ruffling and strong saddle deformations. In the crystal lattice, the [MnIII(TPP)(H2O)]+ cation and the tri­fluoro­methane­sulfonate counter-ions are arranged in alternating planes packed along [001]. The components are linked together through O—H⋯O hydrogen bonds and much weaker C—H⋯O and C—H⋯F inter­actions. The crystal packing is further stabilized by weak C—H⋯π inter­actions involving the pyrrole and phenyl rings of the porphyrin moieties. PMID:27308027

  19. Ligand 5,10,15,20-tetra(N-methyl-4-pyridyl)porphine (TMPyP4) prefers the parallel propeller-type human telomeric G-quadruplex DNA over its other polymorphs.

    PubMed

    Ali, Asfa; Bansal, Manju; Bhattacharya, Santanu

    2015-01-01

    The binding of ligand 5,10,15,20-tetra(N-methyl-4-pyridyl)porphine (TMPyP4) with telomeric and genomic G-quadruplex DNA has been extensively studied. However, a comparative study of interactions of TMPyP4 with different conformations of human telomeric G-quadruplex DNA, namely, parallel propeller-type (PP), antiparallel basket-type (AB), and mixed hybrid-type (MH) G-quadruplex DNA, has not been done. We considered all the possible binding sites in each of the G-quadruplex DNA structures and docked TMPyP4 to each one of them. The resultant most potent sites for binding were analyzed from the mean binding free energy of the complexes. Molecular dynamics simulations were then carried out, and analysis of the binding free energy of the TMPyP4-G-quadruplex complex showed that the binding of TMPyP4 with parallel propeller-type G-quadruplex DNA is preferred over the other two G-quadruplex DNA conformations. The results obtained from the change in solvent excluded surface area (SESA) and solvent accessible surface area (SASA) also support the more pronounced binding of the ligand with the parallel propeller-type G-quadruplex DNA. PMID:25526532

  20. Crystal structure of chlorido-{5,10,15,20-tetra-kis-[2-(2,2-di-methyl-propanamido)-phen-yl]porphyrinato-κ(4) N}iron(III).

    PubMed

    Awasabisah, Dennis; Powell, Douglas R; Richter-Addo, George B

    2015-02-01

    The title compound, [Fe(C64H64N8O4)Cl], is a five-coordinate square-pyramidal porphyrin complex with a chloride ion in the axial position, being coordinated from the protected side of the porphyrin; the Fe(III) atom is displaced by 0.474 (5) Å from the 24-atom mean plane of the porphyrin core towards the chloride. The porphyrin moiety is a 'picket-fence' 5,10,15,20-tetra-kis-[2-(2,2-di-methyl-propanamido)-phen-yl]porph-yrinate (por) group. The Fe-Cl bond length is 2.221 (2) Å and the Fe-N(por) bond lengths are in the range 2.043 (5)-2.063 (5) Å. The supra-molecular architecture of the crystal is sustained by C-H⋯O inter-actions between the pyrrolic and phenyl H atoms of one mol-ecule and the carbonyl O atoms of the 2,2-di-methyl-propanamido groups of adjacent mol-ecules. The methyl groups of three of the four tert-butyl substituents exhibited rotational disorder over two positions. The investigated crystal was twinned by a twofold rotation about the (001) axis with a refined twin ratio of 0.4086 (16). PMID:25878847

  1. Crystal structure of (4-cyano­pyridine-κN){5,10,15,20-tetrakis[4-(benzoyloxy)phenyl]porphyrinato-κ4 N}zinc–4-cyano­pyridine (1/1)

    PubMed Central

    Nasri, Soumaya; Amiri, Nesrine; Turowska-Tyrk, Ilona; Daran, Jean-Claude; Nasri, Habib

    2016-01-01

    In the title compound, [Zn(C72H44N4O8)(C6H4N2)]·C6H4N2 or [Zn(TPBP)(4-CNpy]·(4-CNpy) [where TPBP and 4-CNpy are 5,10,15,20-(tetra­phenyl­benzoate)porphyrinate and 4-cyano­pyridine, respectively], the ZnII cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-CNpy axial ligand in a distorted square-pyramidal geometry. The average Zn—N(pyrrole) bond length is 2.060 (6) Å and the Zn—N(4-CNpy) bond length is 2.159 (2) Å. The zinc cation is displaced by 0.319 (1) Å from the N4C20 mean plane of the porphyrinate anion toward the 4-cyano­pyridine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling and doming deformations. In the crystal, the [Zn(TPBP)(4-CNpy)] complex mol­ecules are linked together via weak C—H⋯N, C—H⋯O and C—H⋯π inter­actions, forming supra­molecular channels parallel to the c axis. The non-coordinating 4-cyano­pyridine mol­ecules are located in the channels and linked with the complex mol­ecules, via weak C—H⋯N inter­actions and π-π stacking or via weak C—H⋯O and C—H⋯π inter­actions. The non-coordinating 4-cyano­pyridine mol­ecule is disordered over two positions with an occupancy ratio of 0.666 (4):0.334 (4). PMID:26958379

  2. Potassium monopersulfate oxidation of 2,4,6-tribromophenol catalyzed by a SiO2-supported iron(III)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin.

    PubMed

    Zhu, Qianqian; Mizutani, Yusuke; Maeno, Shohei; Nishimoto, Ryo; Miyamoto, Takafumi; Fukushima, Masami

    2013-01-01

    Iron(III)-porphyrin complexes are generally regarded as green catalysts, since they mimic the catalytic center of cytochrome-P450 and widely used as green catalysts for degrading halogenated phenols in wastewater, such as landfill leachates. However, iron(III)-porphyrins are deactivated by self-oxidation in the presence of an oxygen donor, such as KHSO5. In the present study, to enhance the reusability of an iron(III)-porphyrin catalyst, iron(III)-5,10,15,20-tetrakis(4-carboxyphenyl) porphyrin (FeTCPP) was immobilized on a functionalized silica gel. The oxidative degradation of 2,4,6-tribromophenol (TrBP), a widely used brominated flame retardant that is found in landfill leachates, was examined using the prepared catalyst. In addition, the influence of humic substances (HSs), major components of leachates, on the TrBP oxidation was investigated. Concerning the effect of pH, more than 90% of the TrBP was degraded in the pH range of 3-8 in the absence of HS, while the optimal pH for the reaction was in the range of pH 5-7 in the presence of HS. Although the oxidation of TrBP was inhibited in the presence of HSs, more than 90% of the TrBP was degraded in the presence of 50 mg L(-1) of HS. Thus, the prepared catalyst, SiO2-FeTCPP, showed a high catalytic activity and could be reused up to 10 times even in the presence of HS. PMID:23947696

  3. Hole transporting material 5, 10, 15-tribenzyl-5H-diindolo[3, 2-a:3‧, 2‧-c]-carbazole for efficient optoelectronic applications as an active layer

    NASA Astrophysics Data System (ADS)

    Zheng, Yan-Qiong; J. Potscavage, William, Jr.; Zhang, Jian-Hua; Wei, Bin; Huang, Rong-Juan

    2015-02-01

    In order to explore the novel application of the transparent hole-transporting material 5,10,15-tribenzyl-5H-diindolo[3,2-a:3‧,2‧-c]-carbazole (TBDI), in this article TBDI is used as an active layer but not a buffer layer in a photodetector (PD), organic light-emitting diode (OLED), and organic photovoltaic cell (OPV) for the first time. Firstly, the absorption and emission spectra of a blend layer comprised of TBDI and electron-transporting material bis-(2-methyl-8-quinolinate) 4-phenylphenolate (BAlq) are investigated. Based on the absorption properties, an organic PD with a peak absorption at 320 nm is fabricated, and a relatively-high detectivity of 2.44 × 1011 cm·Hz1/2/W under 320-nm illumination is obtained. The TBDI/tris (8-hydroxyquinoline) aluminum (Alq3) OLED device exhibits a comparable external quantum efficiency and current efficiency to a traditional 4, 4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD)/Alq3 OLED. A C70-based Schottky junction with 5 wt%-TBDI yields a power conversion efficiency of 5.0%, which is much higher than 1.7% for an α-NPD-based junction in the same configuration. These results suggest that TBDI has some promising properties which are in favor of the hole-transporting in Schottky junctions with a low-concentration donor. Project supported by the Funding Program for World-Leading Innovative R & D on Science and Technology (FIRST) from JSPS, the Fund from the Science and Technology Commission of Shanghai Municipality, China (Grant Nos. 14DZ2280900 and 14XD1401800), and the Natural Science Foundation of Shanghai (Grant No. 15ZR1416600).

  4. Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato-κ4 N}zinc

    PubMed Central

    Nasri, Soumaya; Ezzayani, Khaireddine; Turowska-Tyrk, Ilona; Roisnel, Thierry; Nasri, Habib

    2016-01-01

    The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin­ation geometry about the central ZnII atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro­gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn—N(pyrrole) bond length is 2.078 (7) Å and the Zn— N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra­molecular structure is made by parallel pairs of layers along (100), with an inter­layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol­ecules. The given chemical formula and other crystal data do not take into account these solvent mol­ecules. PMID:27555935

  5. Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato-κ(4) N}zinc.

    PubMed

    Nasri, Soumaya; Ezzayani, Khaireddine; Turowska-Tyrk, Ilona; Roisnel, Thierry; Nasri, Habib

    2016-07-01

    The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin-ation geometry about the central Zn(II) atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro-gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn-N(pyrrole) bond length is 2.078 (7) Å and the Zn- N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra-molecular structure is made by parallel pairs of layers along (100), with an inter-layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol-ecules. The given chemical formula and other crystal data do not take into account these solvent mol-ecules. PMID:27555935

  6. Crystal structure of (4-cyano-pyridine-κN){5,10,15,20-tetrakis[4-(benzoyloxy)phenyl]porphyrinato-κ(4) N}zinc-4-cyano-pyridine (1/1).

    PubMed

    Nasri, Soumaya; Amiri, Nesrine; Turowska-Tyrk, Ilona; Daran, Jean-Claude; Nasri, Habib

    2016-02-01

    In the title compound, [Zn(C72H44N4O8)(C6H4N2)]·C6H4N2 or [Zn(TPBP)(4-CNpy]·(4-CNpy) [where TPBP and 4-CNpy are 5,10,15,20-(tetra-phenyl-benzoate)porphyrinate and 4-cyano-pyridine, respectively], the Zn(II) cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-CNpy axial ligand in a distorted square-pyramidal geometry. The average Zn-N(pyrrole) bond length is 2.060 (6) Å and the Zn-N(4-CNpy) bond length is 2.159 (2) Å. The zinc cation is displaced by 0.319 (1) Å from the N4C20 mean plane of the porphyrinate anion toward the 4-cyano-pyridine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling and doming deformations. In the crystal, the [Zn(TPBP)(4-CNpy)] complex mol-ecules are linked together via weak C-H⋯N, C-H⋯O and C-H⋯π inter-actions, forming supra-molecular channels parallel to the c axis. The non-coordinating 4-cyano-pyridine mol-ecules are located in the channels and linked with the complex mol-ecules, via weak C-H⋯N inter-actions and π-π stacking or via weak C-H⋯O and C-H⋯π inter-actions. The non-coordinating 4-cyano-pyridine mol-ecule is disordered over two positions with an occupancy ratio of 0.666 (4):0.334 (4). PMID:26958379

  7. INO-4885 [5,10,15,20-tetra[N-(benzyl-4'-carboxylate)-2-pyridinium]-21H,23H-porphine iron(III) chloride], a peroxynitrite decomposition catalyst, protects the heart against reperfusion injury in mice.

    PubMed

    Jiao, Xiang-Ying; Gao, Erhe; Yuan, Yuexin; Wang, Yajing; Lau, Wayne Bond; Koch, Walter; Ma, Xin-Liang; Tao, Ling

    2009-03-01

    Oxidative/nitrative stress caused by peroxynitrite, the reaction product of superoxide (O2(.-)) and nitric oxide (NO), is the primary cause of myocardial ischemia/reperfusion injury. The present study determined whether INO-4885 [5,10,15,20-tetra[N-(benzyl-4'-carboxylate)-2-pyridinium]-21H,23H-porphine iron(III) chloride], a new peroxynitrite decomposition catalyst, may provide cellular protection and protect heart from myocardial ischemia/reperfusion injury. Adult male mice were subjected to 30 min of ischemia and 3 or 24 h of reperfusion. Mice were randomized to receive vehicle, INO-4885 without catalytic moiety, or INO-4885 (3-300 microg/kg i.p.) 10 min before reperfusion. Infarct size, apoptosis, nitrotyrosine content, NO/O2(.-) production, and inducible nitric-oxide synthase (iNOS)/NADPH oxidase expression were determined. INO-4885 treatment reduced ischemia/reperfusion-induced protein nitration and caspase 3 activation in a dose-dependent fashion in the range of 3 to 100 microg/kg. However, doses exceeding 100 microg/kg produced nonspecific effects and attenuated its protective ability. At the optimal dose (30 microg/kg), INO-4885 significantly reduced infarct size (p < 0.01), decreased apoptosis (p < 0.01), and reduced tissue nitrotyrosine content (p < 0.01). As expected, INO-4885 had no effect on ischemia/reperfusion-induced iNOS expression and NO overproduction. To our surprise, this compound significantly reduced superoxide production and partially blocked NADPH oxidase overexpression in the ischemic/reperfused cardiac tissue. Additional experiments demonstrated that INO-4885 provided better cardioprotection than N-(3-(aminomethyl)benzyl)acetamidine (1400W, a selective iNOS inhibitor), apocynin (an NADPH oxidase inhibitor), or Tiron (a cell-permeable superoxide scavenger). Taken together, our data demonstrated that INO-4885 is a cardioprotective molecule that attenuates myocardial reperfusion injury by facilitating peroxynitrite decomposition and

  8. Effective exciton blocking by the hole-transporting material 5,10,15-tribenzyl-5H-diindolo[3,2-a:3‧,2‧-c]-carbazole (TBDI) in the tetraphenyldibenzoperiflanthene (DBP) based organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Yang, Fang; Zheng, Yanqiong; Wei, Bin; Zhang, Xiaowen; Zhang, Jianhua; Wang, Zixing; Pu, Wenhong; Yang, Changzhu

    2015-12-01

    To explore the novel application of the hole-transporting material (HTM) as exciton blocking layer (EBL) in small molecule organic photovoltaic (OPV) cells, we introduce a recently reported HTM, 5,10,15-tribenzyl-5H-diindolo[3,2-a:3‧,2‧-c]-carbazole (TBDI), and the other two traditional HTMs, N,N‧-diphenyl-N,N‧-bis(1-naphthyl)-1,1‧-biphenyl-4,4‧-diamine (NPB) and 1,1‧-bis(di-4-tolylaminophenyl) cyclohexane (TAPC), to serve as EBLs in the tetraphenyldibenzoperiflanthene (DBP) based planar heterojunction cells. Due to the large band gap of these materials, the EBLs successfully block the misdirected electrons. The optimized devices including the EBLs of TBDI, NPB and TAPC achieve power conversion efficiency (ηPCE) of 1.70%, 1.33%, and 1.33%, respectively, whereas the control device without any EBL shows a ηPCE of only 1.25%. The optical simulation indicates that the maximum optical electric fields for the PHJs including 10-nm EBLs at the wavelength of 610 nm are significantly enhanced relative to that for the 20-nm DBP based control device. By impedance spectroscopy measurement, the device with TBDI EBL shows lower series resistance and total resistance than the device without TBDI, suggesting fast internal carrier mobility and smaller carrier recombination. The novel HTM TBDI better contributes to the device performance relative to the other two HTMs, stemming from its shallower lowest unoccupied molecule orbits (LUMO) level, stronger prevention of exciton quenching, and a smoother TBDI/DBP surface. These results suggest that TBDI is an excellent candidate as EBL for the DBP based OPVs. The overall ηPCE is further enhanced via optimizing the cathode buffer.

  9. Investigation of the interactions between Pt(II) and Pd(II) derivatives of 5,10,15,20-tetrakis (N-methyl-4-pyridyl) porphyrin and G-quadruplex DNA.

    PubMed

    Sabharwal, Navin C; Mendoza, Oscar; Nicoludis, John M; Ruan, Thomas; Mergny, Jean-Louis; Yatsunyk, Liliya A

    2016-04-01

    G-quadruplexes are non-canonical DNA structures formed by guanine-rich DNA sequences that are implicated in cancer and aging. Understanding how small molecule ligands interact with quadruplexes is essential both to the development of novel anticancer therapeutics and to the design of new quadruplex-selective probes needed for elucidation of quadruplex biological functions. In this work, UV-visible, fluorescence, and circular dichroism spectroscopies, fluorescence resonance energy transfer (FRET) melting assays, and resonance light scattering were used to investigate how the Pt(II) and Pd(II) derivatives of the well-studied 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) interact with quadruplexes formed by the human telomeric DNA, Tel22, and by the G-rich sequences from oncogene promoters. Our results suggest that Pt- and PdTMPyP4 interact with Tel22 via efficient π-π stacking with a binding affinity of 10(6)-10(7) M(-1). Under porphyrin excess, PtTMPyP4 aggregates using Tel22 as a template; the aggregates reach maximum size at [PtTMPyP4]/[Tel22] ~8 and dissolve at [PtTMPyP4]/[Tel22] ≤ 2. FRET assays reveal that both porphyrins are excellent stabilizers of human telomeric DNA, with stabilization temperature of 30.7 ± 0.6 °C for PtTMPyP4 and 30.9 ± 0.4 °C for PdTMPyP4 at [PtTMPyP4]/[Tel22] = 2 in K(+) buffer, values significantly higher as compared to those for TMPyP4. The porphyrins display modest selectivity for quadruplex vs. duplex DNA, with selectivity ratios of 150 and 330 for Pt- and PdTMPyP4, respectively. This selectivity was confirmed by observed 'light switch' effect: fluorescence of PtTMPyP4 increases significantly in the presence of a variety of DNA secondary structures, yet the strongest effect is produced by quadruplex DNA. PMID:26748794

  10. Excitotoxic brain damage involves early peroxynitrite formation in a model of Huntington's disease in rats: protective role of iron porphyrinate 5,10,15,20-tetrakis (4-sulfonatophenyl)porphyrinate iron (III).

    PubMed

    Pérez-De La Cruz, V; González-Cortés, C; Galván-Arzate, S; Medina-Campos, O N; Pérez-Severiano, F; Ali, S F; Pedraza-Chaverrí, J; Santamaría, A

    2005-01-01

    Oxidative/nitrosative stress is involved in NMDA receptor-mediated excitotoxic brain damage produced by the glutamate analog quinolinic acid. The purpose of this work was to study a possible role of peroxynitrite, a reactive oxygen/nitrogen species, in the course of excitotoxic events evoked by quinolinic acid in the brain. The effects of Fe(TPPS) (5,10,15,20-tetrakis (4-sulfonatophenyl)porphyrinate iron (III)), an iron porphyrinate and putative peroxynitrite decomposition catalyst, were tested on lipid peroxidation and mitochondrial function in brain synaptic vesicles exposed to quinolinic acid, as well as on peroxynitrite formation, nitric oxide synthase and superoxide dismutase activities, lipid peroxidation, caspase-3-like activation, DNA fragmentation, and GABA levels in striatal tissue from rats lesioned by quinolinic acid. Circling behavior was also evaluated. Increasing concentrations of Fe(TPPS) reduced lipid peroxidation and mitochondrial dysfunction induced by quinolinic acid (100 microM) in synaptic vesicles in a concentration-dependent manner (10-800 microM). In addition, Fe(TPPS) (10 mg/kg, i.p.) administered 2 h before the striatal lesions, prevented the formation of peroxynitrite, the increased nitric oxide synthase activity, the decreased superoxide dismutase activity and the increased lipid peroxidation induced by quinolinic acid (240 nmol/microl) 120 min after the toxin infusion. Enhanced caspase-3-like activity and DNA fragmentation were also reduced by the porphyrinate 24 h after the injection of the excitotoxin. Circling behavior from quinolinic acid-treated rats was abolished by Fe(TPPS) six days after quinolinic acid injection, while the striatal levels of GABA, measured one day later, were partially recovered. The protective effects that Fe(TPPS) exerted on quinolinic acid-induced lipid peroxidation and mitochondrial dysfunction in synaptic vesicles suggest a primary action of the porphyrinate as an antioxidant molecule. In vivo findings

  11. Sol-gel synthesis of quaternary (P2O5)55-(CaO)25-(Na2O)(20-x)-(TiO2) x bioresorbable glasses for bone tissue engineering applications (x = 0, 5, 10, or 15).

    PubMed

    Foroutan, Farzad; Walters, Nick J; Owens, Gareth J; Mordan, Nicola J; Kim, Hae-Won; de Leeuw, Nora H; Knowles, Jonathan C

    2015-08-01

    In the present study, we report a new and facile sol-gel synthesis of phosphate-based glasses with the general formula of (P2O5)55-(CaO)25-(Na2O)(20-x)-(TiO2) x , where x = 0, 5, 10 or 15, for bone tissue engineering applications. The sol-gel synthesis method allows greater control over glass morphology at relatively low processing temperature (200 °C) in comparison with phosphate-based melt-derived glasses (~1000 °C). The glasses were analyzed using several characterization techniques, including x-ray diffraction (XRD), (31)P magic angle spinning nuclear magnetic resonance ((31)P MAS-NMR), Fourier transform infrared (FTIR) spectroscopy and energy-dispersive x-ray (EDX) spectroscopy, which confirmed the amorphous and glassy nature of the prepared samples. Degradation was assessed by measuring the ion release and pH change of the storage medium. Cytocompatibility was also confirmed by culturing osteoblast-like osteosarcoma cell line MG-63 on the glass microparticles over a seven-day period. Cell attachment to the particles was imaged using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results revealed the potential of phosphate-based sol-gel derived glasses containing 5 or 10 mol% TiO2, with high surface area, ideal dissolution rate for cell attachment and easily metabolized dissolution products, for bone tissue engineering applications. PMID:26306553

  12. Ring-strain release in neutral and dicationic 7,8,17,18-tetra-bromo-5,10,15,20-tetra-phenyl-porphyrin: crystal structures of C44H26Br4N4 and C44H28Br4N4 (2+)·2ClO4 (-)·3CH2Cl2.

    PubMed

    Scheidt, W Robert; Duval, Hugues F; Oliver, Allen G

    2016-06-01

    Two porphyrin complexes were studied to determine the effects of protonation on ring deformation within the porphyrin. The porphyrin 7,8,17,18-tetra-bromo-5,10,15,20-tetra-phenyl-porphyrin, C44H26Br4N4, was selected because the neutral species is readily doubly protonated to yield a dication, which was crystallized here with perchlorate counter-ions as a di-chloro-methane tris-olvate, C44H28Br4N4 (2+)·2ClO4 (-)·3CH2Cl2. The centrosymmetric neutral species is observed to have a mild 'ruffling' of the pyrrole rings and is essentially planar throughout; intra-molecular N-H⋯N hydrogen bonds occur. In contrast, the dication exhibits considerable deformation, with the pyrrole rings oriented well out of the plane of the porphyrin, resulting in a 'saddle' conformation of the ring. The charged species forms N-H⋯O hydrogen bonds to the perchlorate anions, which lie above and below the plane of the porphyrin ring. Distortions to the planarity of the pyrrole rings in both cases are very minor. The characterization of the neutral species represents a low-temperature redetermination of the previous room-temperature analyses [Zou et al. (1995 ▸). Acta Cryst. C51, 760-761; Rayati et al. (2008 ▸). Polyhedron, pp. 2285-2290], which showed disorder and physically unrealistic displacement parameters. PMID:27308051

  13. Crystal structure of di­aqua­[5,10,15,20-tetra­kis­(4-meth­oxy­phen­yl)porphyrinato-κ4 N]iron(III) di­aqua­(18-crown-6)potassium bis­(tri­fluoro­methane­sulfonate)–18-crown-6 (1/2)

    PubMed Central

    Ben Haj Hassen, Leila; Denden, Zouhour; Rousselin, Yoann; Nasri, Habib

    2015-01-01

    In the title compound, [FeIII(C48H36N4O2)(H2O)2][K(C12H24O6)(H2O)2](SO3CF3)2·2C12H24O6, the FeIII atom is situated on an inversion centre and is octa­hedrally coordin­ated by four pyrrole N atoms of the deprotenated 5,10,15,20-tetra­kis­(4-meth­oxy­phen­yl)porphyrinate ligand and two water mol­ecules. The average equatorial Fe—N(pyrrole) bond length [2.043 (6) Å] is consistent with a high-spin (S = 5/2) iron(III) metalloporphyrin derivative. The K+ cation, which also lies on an inversion centre, is chelated by the six O atoms of one 18-crown-6 mol­ecule and is additionally coordinated by two water mol­ecules in a distorted hexa­gonal–bipyramidal geometry. In the crystal, the cations, anions and one non-coordinating 18-crown-6 mol­ecule are linked by classical O—H⋯O hydrogen bonds and non-conventional C—H⋯O hydrogen bonds, leading to a one-dimensional supra­molecular architecture along [10-1]. The crystal packing is further stabilized by weak C—H⋯π inter­actions involving pyrrole and phenyl rings of the porphyrins, as well as weak C—H⋯F contacts involving the (SO3CF3)− counter-ion and the 18-crown-6 mol­ecules. PMID:26870431

  14. Crystal structure of di-aqua-[5,10,15,20-tetra-kis-(4-meth-oxy-phen-yl)porphyrinato-κ(4) N]iron(III) di-aqua-(18-crown-6)potassium bis-(tri-fluoro-methane-sulfonate)-18-crown-6 (1/2).

    PubMed

    Ben Haj Hassen, Leila; Denden, Zouhour; Rousselin, Yoann; Nasri, Habib

    2015-12-01

    In the title compound, [Fe(III)(C48H36N4O2)(H2O)2][K(C12H24O6)(H2O)2](SO3CF3)2·2C12H24O6, the Fe(III) atom is situated on an inversion centre and is octa-hedrally coordin-ated by four pyrrole N atoms of the deprotenated 5,10,15,20-tetra-kis-(4-meth-oxy-phen-yl)porphyrinate ligand and two water mol-ecules. The average equatorial Fe-N(pyrrole) bond length [2.043 (6) Å] is consistent with a high-spin (S = 5/2) iron(III) metalloporphyrin derivative. The K(+) cation, which also lies on an inversion centre, is chelated by the six O atoms of one 18-crown-6 mol-ecule and is additionally coordinated by two water mol-ecules in a distorted hexa-gonal-bipyramidal geometry. In the crystal, the cations, anions and one non-coordinating 18-crown-6 mol-ecule are linked by classical O-H⋯O hydrogen bonds and non-conventional C-H⋯O hydrogen bonds, leading to a one-dimensional supra-molecular architecture along [10-1]. The crystal packing is further stabilized by weak C-H⋯π inter-actions involving pyrrole and phenyl rings of the porphyrins, as well as weak C-H⋯F contacts involving the (SO3CF3)(-) counter-ion and the 18-crown-6 mol-ecules. PMID:26870431

  15. Ring-strain release in neutral and dicationic 7,8,17,18-tetra­bromo-5,10,15,20-tetra­phenyl­porphyrin: crystal structures of C44H26Br4N4 and C44H28Br4N4 2+·2ClO4 −·3CH2Cl2

    PubMed Central

    Scheidt, W. Robert; Duval, Hugues F.; Oliver, Allen G.

    2016-01-01

    Two porphyrin complexes were studied to determine the effects of protonation on ring deformation within the porphyrin. The porphyrin 7,8,17,18-tetra­bromo-5,10,15,20-tetra­phenyl­porphyrin, C44H26Br4N4, was selected because the neutral species is readily doubly protonated to yield a dication, which was crystallized here with perchlorate counter-ions as a di­chloro­methane tris­olvate, C44H28Br4N4 2+·2ClO4 −·3CH2Cl2. The centrosymmetric neutral species is observed to have a mild ‘ruffling’ of the pyrrole rings and is essentially planar throughout; intra­molecular N—H⋯N hydrogen bonds occur. In contrast, the dication exhibits considerable deformation, with the pyrrole rings oriented well out of the plane of the porphyrin, resulting in a ‘saddle’ conformation of the ring. The charged species forms N—H⋯O hydrogen bonds to the perchlorate anions, which lie above and below the plane of the porphyrin ring. Distortions to the planarity of the pyrrole rings in both cases are very minor. The characterization of the neutral species represents a low-temperature redetermination of the previous room-temperature analyses [Zou et al. (1995 ▸). Acta Cryst. C51, 760–761; Rayati et al. (2008 ▸). Polyhedron, pp. 2285–2290], which showed disorder and physically unrealistic displacement parameters. PMID:27308051

  16. Pure manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is not a superoxide dismutase mimic in aqueous systems: a case of structure-activity relationship as a watchdog mechanism in experimental therapeutics and biology.

    PubMed

    Rebouças, Júlio S; Spasojević, Ivan; Batinić-Haberle, Ines

    2008-02-01

    Superoxide is involved in a plethora of pathological and physiological processes via oxidative stress and/or signal transduction pathways. Superoxide dismutase (SOD) mimics have, thus, been actively sought for clinical and mechanistic purposes. Manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is one of the most intensely explored "SOD mimics" in biology and medicine. However, we show here that this claimed SOD activity of MnTBAP in aqueous media is not corroborated by comprehensive structure-activity relationship studies for a wide set of Mn porphyrins and that MnTBAP from usual commercial sources contains different amounts of noninnocent trace impurities (Mn clusters), which inhibited xanthine oxidase and had SOD activity in their own right. In addition, the preparation and thorough characterization of a high-purity MnTBAP is presented for the first time and confirmed that pure MnTBAP has no SOD activity in aqueous medium. These findings call for an assessment of the relevance and suitability of using MnTBAP (or its impurities) as a mechanistic probe and antioxidant therapeutic; conclusions on the physiological and pathological role of superoxide derived from studies using MnTBAP of uncertain purity should be examined judiciously. An unequivocal distinction between the biological effects due to MnTBAP and that of its impurities can only be unambiguously made if a pure sample is/was used. This work also illustrates the contribution of fundamental structure-activity relationship studies not only for drug design and optimization, but also as a "watchdog" mechanism for checking/spotting eventual incongruence of drug activity in chemical and biological settings. PMID:18046586

  17. (2.2.2-Cryptand)potassium bis­(cyanato-κN)(5,10,15,20-tetra­phenyl­por­phy­rin­ato-κ4 N)cobaltate(III) chloro­benzene hemisolvate

    PubMed Central

    Belhaj Ali, Bader; Belkhiria, Mohamed Salah; Daran, Jean-Claude; Nasri, Habib

    2012-01-01

    In the title compound, [K(C18H36N2O6)][Co(NCO)2(C44H28N4)]·0.5C6H5Cl or [K(2,2,2-crypt)+][CoIII(NCO)2(TPP)−]·0.5C6H5Cl, the CoIII ion is octa­hedrally coordin­ated by two axial N-bonded NCO− anions and four pyrrole N atoms of the porphyrin. There is a major ruffling distortion of the porphyrin: the dihedral angles between trans pyrrole rings are 34.32 (14) and 34.72 (14)°. The potassium ion is coordinated by the six O atoms and two N atoms of the cryptand-222 mol­ecule and a weak K—O [3.407 (3) Å] bond to one of the cyanate O atoms also occurs. The packing also features weak C—H⋯O and C—H⋯π inter­actions. The contribution to the scattering of the disordered chloro­benzene solvent mol­ecules was removed with the SQUEEZE function in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. PMID:23125591

  18. LIME 0.5

    SciTech Connect

    2011-01-14

    LIME 0.5 is an initial version of a Lightweight Integrating Multi-physics Environment for coupling codes. LIME by itself is not a code for doing multiphysics simulations. Instead, LIME provides the key high-level software, a flexible but defined approach, and interface requirements for a collection of (potentially disparate) physics codes to be combined with strong coupling (when needed) though non-linear solution methods (e.g. JFNK, fixed point), thus creating a new multi-physics simulation capability customized for a particular need. ! ! The approach taken is designed to! •! preserve and leverage any important specialized algorithms and/or functionality an existing application may provide,! •! minimize the requirements barrier for an application to participate,! •! work within advanced solver frameworks (e.g. as extensions to the Trilinos/NOX nonlinear solver libraries, PETSc, . . .),! Of note is that components/physics codes that can be coupled within LIME are NOT limited to:! •! components written in one particular language,! •! a particular numerical discretization approach ( e.g. Finite Element), or! •! physical models expressed as PDEʼs.!

  19. LIME 0.5

    2011-01-14

    LIME 0.5 is an initial version of a Lightweight Integrating Multi-physics Environment for coupling codes. LIME by itself is not a code for doing multiphysics simulations. Instead, LIME provides the key high-level software, a flexible but defined approach, and interface requirements for a collection of (potentially disparate) physics codes to be combined with strong coupling (when needed) though non-linear solution methods (e.g. JFNK, fixed point), thus creating a new multi-physics simulation capability customized for amore » particular need. ! ! The approach taken is designed to! •! preserve and leverage any important specialized algorithms and/or functionality an existing application may provide,! •! minimize the requirements barrier for an application to participate,! •! work within advanced solver frameworks (e.g. as extensions to the Trilinos/NOX nonlinear solver libraries, PETSc, . . .),! Of note is that components/physics codes that can be coupled within LIME are NOT limited to:! •! components written in one particular language,! •! a particular numerical discretization approach ( e.g. Finite Element), or! •! physical models expressed as PDEʼs.!« less

  20. 46 CFR 76.10-15 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.10-15 Section 76.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Fire Main System, Details § 76.10-15 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements...

  1. 46 CFR 95.10-15 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 95.10-15 Section 95.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Fire Main System, Details § 95.10-15 Piping. (a) All piping, valves, and fittings shall meet the...

  2. 46 CFR 193.10-15 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Piping. 193.10-15 Section 193.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS FIRE PROTECTION EQUIPMENT Fire Main System, Details § 193.10-15 Piping. (a) All piping, valves, and fittings, shall meet...

  3. 46 CFR 188.10-15 - Coastwise.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-15 Coastwise. Under this designation shall be included all vessels normally navigating the waters of any ocean or the Gulf of Mexico 20 nautical miles...

  4. 46 CFR 188.10-15 - Coastwise.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-15 Coastwise. Under this designation shall be included all vessels normally navigating the waters of any ocean or the Gulf of Mexico 20 nautical miles...

  5. 46 CFR 188.10-15 - Coastwise.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-15 Coastwise. Under this designation shall be included all vessels normally navigating the waters of any ocean or the Gulf of Mexico 20 nautical miles...

  6. Weight loss and fillet quality characteristics of Atlantic salmon (Salmo salar) after purging for 5, 10, 15 or 20 days

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atlantic salmon, Salmo salar, are typically cultured in marine net pens. However, technological advancements in recirculating aquaculture systems have increased the feasibility of culturing Atlantic salmon in land-based systems to alleviate environmental and disease issues limiting sustainability. ...

  7. 43 CFR 2920.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 2920.0-5 Section 2920.0-5... Easements: General Provisions § 2920.0-5 Definitions. As used in this part, the term: (a) Authorized officer... Land Management to use and manage the lands in a manner consistent with the terms of the easement....

  8. 43 CFR 2091.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 2091.0-5 Section 2091.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.0-5 Definitions. As used in...

  9. 43 CFR 2091.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Definitions. 2091.0-5 Section 2091.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.0-5 Definitions. As used in...

  10. 43 CFR 2300.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Definitions. 2300.0-5 Section 2300.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) LAND WITHDRAWALS Withdrawals, General § 2300.0-5 Definitions. As used in this part, the term:...

  11. 28 CFR 0.5 - Attorney General.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 1 2013-07-01 2013-07-01 false Attorney General. 0.5 Section 0.5 Judicial Administration DEPARTMENT OF JUSTICE ORGANIZATION OF THE DEPARTMENT OF JUSTICE Office of the Attorney General § 0.5 Attorney General. The Attorney General shall: (a) Supervise and direct...

  12. 43 CFR 2610.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 2610.0-5 Section 2610.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) CAREY ACT GRANTS Carey Act Grants, General § 2610.0-5 Definitions. As used in the...

  13. 43 CFR 2300.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 2300.0-5 Section 2300.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) LAND WITHDRAWALS Withdrawals, General § 2300.0-5 Definitions. As used in this part, the term:...

  14. 43 CFR 2911.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 2911.0-5 Section 2911.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) LEASES Airport § 2911.0-5 Definitions. As used in this subpart, the term: (a) Act means the...

  15. 43 CFR 8223.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Definitions. 8223.0-5 Section 8223.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RECREATION PROGRAMS PROCEDURES Research Natural Areas § 8223.0-5 Definitions....

  16. 43 CFR 1784.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 1784.0-5 Section 1784.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR GENERAL MANAGEMENT (1000) COOPERATIVE RELATIONS Advisory Committees § 1784.0-5 Definitions. As used in this subpart, the...

  17. 43 CFR 8223.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 8223.0-5 Section 8223.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RECREATION PROGRAMS PROCEDURES Research Natural Areas § 8223.0-5 Definitions....

  18. Giant dielectric permittivity and weak ferromagnetic behavior in Bi0.5La0.5Fe0.5Cr0.5O3 ceramic

    NASA Astrophysics Data System (ADS)

    Tirupathi, Patri; Raju, K.; Peetla, Naresh; Pantangi, Ramakrishna; Pastor, Mukul

    2016-05-01

    A pervoskite (Bi0.5La0.5)(Fe0.5Cr0.5)O3 (BLFC) nanoparticles were synthesized by high energy ball milling. Rietveld refined X-ray diffraction studies revealed that this compound shows orthorhombic structure with Pbnm space group. The dielectric studies were investigated in wide frequency (102-106) range indicating giant dielectric permittivity behavior similar to LaFeO3 ceramic. The noted dielectric loss relaxation frequency dependent is as following the Arrhenius law can be ascribed as polaronic conduction. Further, magnetic transition at around 337 K and coexistence of weak ferromagnetic and antiferromagnetic behavior is observed below magnetic transition.

  19. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Aids to navigation. 66.10-15 Section 66.10-15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Uniform State Waterway Marking System § 66.10-15 Aids to navigation....

  20. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Aids to navigation. 66.10-15 Section 66.10-15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Uniform State Waterway Marking System § 66.10-15 Aids to navigation....

  1. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Aids to navigation. 66.10-15 Section 66.10-15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Uniform State Waterway Marking System § 66.10-15 Aids to navigation....

  2. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Aids to navigation. 66.10-15 Section 66.10-15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Uniform State Waterway Marking System § 66.10-15 Aids to navigation....

  3. 33 CFR 66.10-15 - Aids to navigation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Aids to navigation. 66.10-15 Section 66.10-15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Uniform State Waterway Marking System § 66.10-15 Aids to navigation....

  4. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine...

  5. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine...

  6. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine...

  7. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine...

  8. 46 CFR 90.10-15 - Industrial personnel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Industrial personnel. 90.10-15 Section 90.10-15 Shipping... PROVISIONS Definition of Terms Used in This Subchapter § 90.10-15 Industrial personnel. This term means every person carried on board an industrial vessel for the sole purpose of carrying out the industrial...

  9. 46 CFR 90.10-15 - Industrial personnel.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Industrial personnel. 90.10-15 Section 90.10-15 Shipping... PROVISIONS Definition of Terms Used in This Subchapter § 90.10-15 Industrial personnel. This term means every person carried on board an industrial vessel for the sole purpose of carrying out the industrial...

  10. 46 CFR 90.10-15 - Industrial personnel.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Industrial personnel. 90.10-15 Section 90.10-15 Shipping... PROVISIONS Definition of Terms Used in This Subchapter § 90.10-15 Industrial personnel. This term means every person carried on board an industrial vessel for the sole purpose of carrying out the industrial...

  11. 46 CFR 90.10-15 - Industrial personnel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Industrial personnel. 90.10-15 Section 90.10-15 Shipping... PROVISIONS Definition of Terms Used in This Subchapter § 90.10-15 Industrial personnel. This term means every person carried on board an industrial vessel for the sole purpose of carrying out the industrial...

  12. 46 CFR 90.10-15 - Industrial personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Industrial personnel. 90.10-15 Section 90.10-15 Shipping... PROVISIONS Definition of Terms Used in This Subchapter § 90.10-15 Industrial personnel. This term means every person carried on board an industrial vessel for the sole purpose of carrying out the industrial...

  13. 46 CFR 105.10-15 - Flammable liquid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Flammable liquid. 105.10-15 Section 105.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Definition of Terms Used in This Part § 105.10-15 Flammable liquid. (a) The term flammable liquid...

  14. 46 CFR 105.10-15 - Flammable liquid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Flammable liquid. 105.10-15 Section 105.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Definition of Terms Used in This Part § 105.10-15 Flammable liquid. (a) The term flammable liquid...

  15. 46 CFR 34.10-15 - Piping-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Piping-T/ALL. 34.10-15 Section 34.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS FIREFIGHTING EQUIPMENT Fire Main System, Details § 34.10-15 Piping—T/ALL. (a) All piping, valves and fittings shall meet the applicable requirements...

  16. 49 CFR 10.15 - Protection of records.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Protection of records. 10.15 Section 10.15... INDIVIDUALS General § 10.15 Protection of records. (a) No person may, without permission, remove any record... authority, sells, conveys or disposes of any record * * * or thing of value of the United States or of...

  17. 49 CFR 10.15 - Protection of records.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Protection of records. 10.15 Section 10.15... INDIVIDUALS General § 10.15 Protection of records. (a) No person may, without permission, remove any record... authority, sells, conveys or disposes of any record * * * or thing of value of the United States or of...

  18. 49 CFR 10.15 - Protection of records.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Protection of records. 10.15 Section 10.15... INDIVIDUALS General § 10.15 Protection of records. (a) No person may, without permission, remove any record... authority, sells, conveys or disposes of any record * * * or thing of value of the United States or of...

  19. 49 CFR 10.15 - Protection of records.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Protection of records. 10.15 Section 10.15... INDIVIDUALS General § 10.15 Protection of records. (a) No person may, without permission, remove any record... authority, sells, conveys or disposes of any record * * * or thing of value of the United States or of...

  20. 49 CFR 10.15 - Protection of records.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Protection of records. 10.15 Section 10.15... INDIVIDUALS General § 10.15 Protection of records. (a) No person may, without permission, remove any record... authority, sells, conveys or disposes of any record * * * or thing of value of the United States or of...

  1. 46 CFR 151.10-15 - Certificate endorsement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Certificate endorsement. 151.10-15 Section 151.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Barge Hull Construction Requirements § 151.10-15 Certificate endorsement. (a)-(b) (c)...

  2. 46 CFR 50.10-15 - Marine inspector or inspector.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Marine inspector or inspector. 50.10-15 Section 50.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 50.10-15 Marine inspector or inspector. The term...

  3. 46 CFR 50.10-15 - Marine inspector or inspector.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Marine inspector or inspector. 50.10-15 Section 50.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 50.10-15 Marine inspector or inspector. The term...

  4. 46 CFR 50.10-15 - Marine inspector or inspector.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Marine inspector or inspector. 50.10-15 Section 50.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 50.10-15 Marine inspector or inspector. The term...

  5. 46 CFR 50.10-15 - Marine inspector or inspector.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Marine inspector or inspector. 50.10-15 Section 50.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 50.10-15 Marine inspector or inspector. The term...

  6. 46 CFR 50.10-15 - Marine inspector or inspector.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Marine inspector or inspector. 50.10-15 Section 50.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 50.10-15 Marine inspector or inspector. The term...

  7. 46 CFR 59.10-15 - Rivets and staybolts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Rivets and staybolts. 59.10-15 Section 59.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING REPAIRS TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service § 59.10-15...

  8. 46 CFR 59.10-15 - Rivets and staybolts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Rivets and staybolts. 59.10-15 Section 59.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING REPAIRS TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service § 59.10-15...

  9. 46 CFR 190.10-15 - Vertical ladders not accepted.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Vertical ladders not accepted. 190.10-15 Section 190.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 190.10-15 Vertical ladders not accepted. (a) Vertical...

  10. 46 CFR 190.10-15 - Vertical ladders not accepted.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Vertical ladders not accepted. 190.10-15 Section 190.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 190.10-15 Vertical ladders not accepted. (a) Vertical ladders and deck scuttles shall not in general...

  11. Site symmetry of Er3+ in In0.5Ga0.5P

    NASA Astrophysics Data System (ADS)

    Jeong, B. S.; Hong, Y. K.; An, J. Y.; Choi, J. C.; Chung, C. H.; Park, H. L.

    1995-01-01

    The site and site symmetry of Er3+ in LPE grown In0.5Ga0.5P have been investigated for the first time through Raman and polarized luminescence spectroscopic techniques. The Er3+ site was found to be ErIn in In0.5Ga0.5P. The site symmetry of Er3+ in In0.5Ga0.5P was positively confirmed asC2v.

  12. 43 CFR 2920.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Definitions. 2920.0-5 Section 2920.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) LEASES, PERMITS AND EASEMENTS Leases, Permits and Easements: General Provisions §...

  13. 43 CFR 3142.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Definitions. 3142.0-5 Section 3142.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Paying...

  14. 43 CFR 3142.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 3142.0-5 Section 3142.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Paying...

  15. 43 CFR 3142.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Definitions. 3142.0-5 Section 3142.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Paying...

  16. 43 CFR 3142.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 3142.0-5 Section 3142.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Paying...

  17. 43 CFR 9212.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 9212.0-5 Section 9212.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) FIRE MANAGEMENT Wildfire Prevention §...

  18. 43 CFR 9212.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Definitions. 9212.0-5 Section 9212.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) FIRE MANAGEMENT Wildfire Prevention §...

  19. 43 CFR 9212.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Definitions. 9212.0-5 Section 9212.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) FIRE MANAGEMENT Wildfire Prevention §...

  20. 43 CFR 9212.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 9212.0-5 Section 9212.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) FIRE MANAGEMENT Wildfire Prevention §...

  1. 43 CFR 4700.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 4700.0-5 Section 4700.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS General §...

  2. 43 CFR 2300.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Definitions. 2300.0-5 Section 2300.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... employee of the Bureau of Land Management to whom has been delegated the authority to perform the...

  3. 43 CFR 2911.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Definitions. 2911.0-5 Section 2911.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT...). (b) Authorized officer means any employee of the Bureau of Land Management who has been delegated...

  4. 43 CFR 8340.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Definitions. 8340.0-5 Section 8340.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Bureau of Land Management. (c) Bureau means the Bureau of Land Management. (d) Official use means use...

  5. 43 CFR 8340.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Definitions. 8340.0-5 Section 8340.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Bureau of Land Management. (c) Bureau means the Bureau of Land Management. (d) Official use means use...

  6. 43 CFR 4100.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Definitions. 4100.0-5 Section 4100.0-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Grazing Administration-Exclusive of Alaska; General §...

  7. 43 CFR 1815.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....0-5 Definitions. Major disaster means any hurricane, tornado, storm, flood, high water, winddriven..., which, in the determination of the President, is or threatens to be of sufficient severity and...

  8. 43 CFR 1815.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....0-5 Definitions. Major disaster means any hurricane, tornado, storm, flood, high water, winddriven..., which, in the determination of the President, is or threatens to be of sufficient severity and...

  9. 43 CFR 1815.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ....0-5 Definitions. Major disaster means any hurricane, tornado, storm, flood, high water, winddriven..., which, in the determination of the President, is or threatens to be of sufficient severity and...

  10. 43 CFR 1815.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....0-5 Definitions. Major disaster means any hurricane, tornado, storm, flood, high water, winddriven..., which, in the determination of the President, is or threatens to be of sufficient severity and...

  11. 43 CFR 2520.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) DESERT-LAND ENTRIES Desert-Land Entries: General § 2520.0-5 Definitions. (a) As used in the desert-land laws and the regulations of this subpart:...

  12. 43 CFR 2520.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) DESERT-LAND ENTRIES Desert-Land Entries: General § 2520.0-5 Definitions. (a) As used in the desert-land laws and the regulations of this subpart:...

  13. 43 CFR 2520.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) DESERT-LAND ENTRIES Desert-Land Entries: General § 2520.0-5 Definitions. (a) As used in the desert-land laws and the regulations of this subpart:...

  14. 43 CFR 2520.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) DESERT-LAND ENTRIES Desert-Land Entries: General § 2520.0-5 Definitions. (a) As used in the desert-land laws and the regulations of this subpart:...

  15. 20 CFR 10.15 - May compensation rights be waived?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false May compensation rights be waived? 10.15 Section 10.15 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT,...

  16. 20 CFR 10.15 - May compensation rights be waived?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true May compensation rights be waived? 10.15 Section 10.15 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT,...

  17. 46 CFR 53.10-15 - Manufacturers' data report forms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Vessel Code (incorporated by reference; see 46 CFR 53.01-1) must be made available to the marine... 46 Shipping 2 2013-10-01 2013-10-01 false Manufacturers' data report forms. 53.10-15 Section 53.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING...

  18. 46 CFR 53.10-15 - Manufacturers' data report forms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Vessel Code (incorporated by reference; see 46 CFR 53.01-1) must be made available to the marine... 46 Shipping 2 2011-10-01 2011-10-01 false Manufacturers' data report forms. 53.10-15 Section 53.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING...

  19. 46 CFR 53.10-15 - Manufacturers' data report forms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Vessel Code (incorporated by reference; see 46 CFR 53.01-1) must be made available to the marine... 46 Shipping 2 2014-10-01 2014-10-01 false Manufacturers' data report forms. 53.10-15 Section 53.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING...

  20. 46 CFR 53.10-15 - Manufacturers' data report forms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Vessel Code (incorporated by reference; see 46 CFR 53.01-1) must be made available to the marine... 46 Shipping 2 2012-10-01 2012-10-01 false Manufacturers' data report forms. 53.10-15 Section 53.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING...

  1. 46 CFR 53.10-15 - Manufacturers' data report forms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Vessel Code (incorporated by reference; see 46 CFR 53.01-1) must be made available to the marine... 46 Shipping 2 2010-10-01 2010-10-01 false Manufacturers' data report forms. 53.10-15 Section 53.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING...

  2. 43 CFR 3150.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... placing explosive charges, where permissible, for seismic exploration. (b) Casual use means activities..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ONSHORE OIL AND GAS GEOPHYSICAL EXPLORATION Onshore Oil and Gas Geophysical Exploration; General § 3150.0-5 Definitions. As used in this part, the term:...

  3. 43 CFR 3141.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.0-5 Definitions. As used in this subpart, the term: (a) Combined hydrocarbon lease means a lease issued in a Special Tar Sand Area for the removal of any gas and...

  4. 43 CFR 3141.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.0-5 Definitions. As used in this subpart, the term: (a) Combined hydrocarbon lease means a lease issued in a Special Tar Sand Area for the removal of any gas and...

  5. 43 CFR 3141.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.0-5 Definitions. As used in this subpart, the term: (a) Combined hydrocarbon lease means a lease issued in a Special Tar Sand Area for the removal of any gas and...

  6. 43 CFR 3141.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.0-5 Definitions. As used in this subpart, the term: (a) Combined hydrocarbon lease means a lease issued in a Special Tar Sand Area for the removal of any gas and...

  7. 43 CFR 8224.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR RECREATION PROGRAMS PROCEDURES Fossil Forest Research Natural Area § 8224.0-5..., bitumen, lignite, asphaltum and tar sands, even though they are of biologic origin: (c) Fossil Forest or Fossil Forest Research Natural Area means those public lands as described in section 103(a) of the...

  8. 43 CFR 2300.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) LAND WITHDRAWALS Withdrawals, General § 2300.0-5... employee of the Bureau of Land Management to whom has been delegated the authority to perform the...

  9. 43 CFR 3180.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ONSHORE OIL AND GAS UNIT AGREEMENTS: UNPROVEN AREAS Onshore Oil and Gas Unit Agreements: General § 3180.0-5 Definitions. The following terms, as used in this... or plan. Unitized substances. Deposits of oil and gas contained in the unitized land which...

  10. 43 CFR 3130.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING: NATIONAL PETROLEUM RESERVE, ALASKA Oil and Gas Leasing, National Petroleum Reserve, Alaska: General § 3130.0-5 Definitions. As used in... exploring, testing, surveying or otherwise investigating the potential of a lease for oil and gas or...

  11. 43 CFR 3130.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING: NATIONAL PETROLEUM RESERVE, ALASKA Oil and Gas Leasing, National Petroleum Reserve, Alaska: General § 3130.0-5 Definitions. As used in... exploring, testing, surveying or otherwise investigating the potential of a lease for oil and gas or...

  12. 43 CFR 3180.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ONSHORE OIL AND GAS UNIT AGREEMENTS: UNPROVEN AREAS Onshore Oil and Gas Unit Agreements: General § 3180.0-5 Definitions. The following terms, as used in this... or plan. Unitized substances. Deposits of oil and gas contained in the unitized land which...

  13. 43 CFR 3180.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ONSHORE OIL AND GAS UNIT AGREEMENTS: UNPROVEN AREAS Onshore Oil and Gas Unit Agreements: General § 3180.0-5 Definitions. The following terms, as used in this... or plan. Unitized substances. Deposits of oil and gas contained in the unitized land which...

  14. 43 CFR 3180.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ONSHORE OIL AND GAS UNIT AGREEMENTS: UNPROVEN AREAS Onshore Oil and Gas Unit Agreements: General § 3180.0-5 Definitions. The following terms, as used in this... or plan. Unitized substances. Deposits of oil and gas contained in the unitized land which...

  15. 43 CFR 3130.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING: NATIONAL PETROLEUM RESERVE, ALASKA Oil and Gas Leasing, National Petroleum Reserve, Alaska: General § 3130.0-5 Definitions. As used in... exploring, testing, surveying or otherwise investigating the potential of a lease for oil and gas or...

  16. 43 CFR 3130.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING: NATIONAL PETROLEUM RESERVE, ALASKA Oil and Gas Leasing, National Petroleum Reserve, Alaska: General § 3130.0-5 Definitions. As used in... exploring, testing, surveying or otherwise investigating the potential of a lease for oil and gas or...

  17. 43 CFR 8224.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR RECREATION PROGRAMS PROCEDURES Fossil Forest Research Natural Area § 8224.0-5... Land Management designated to perform the duties described in this subpart: (b) Fossil means the..., bitumen, lignite, asphaltum and tar sands, even though they are of biologic origin: (c) Fossil Forest...

  18. 43 CFR 8224.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR RECREATION PROGRAMS PROCEDURES Fossil Forest Research Natural Area § 8224.0-5... Land Management designated to perform the duties described in this subpart: (b) Fossil means the..., bitumen, lignite, asphaltum and tar sands, even though they are of biologic origin: (c) Fossil Forest...

  19. 43 CFR 8224.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR RECREATION PROGRAMS PROCEDURES Fossil Forest Research Natural Area § 8224.0-5... Land Management designated to perform the duties described in this subpart: (b) Fossil means the..., bitumen, lignite, asphaltum and tar sands, even though they are of biologic origin: (c) Fossil Forest...

  20. 43 CFR 3400.0-5 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-5 Definitions. As used in this group: (a) Alluvial valley floor has the meaning set forth in 30 CFR... consistent with 40 CFR 1508.9. (k) Exploration has the meaning set forth in § 3480.0-5(a)(17) of this title... approved mining or exploration plan. This is the same as the Federal lease bond referred to in 30 CFR...

  1. 43 CFR 3400.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-5 Definitions. As used in this group: (a) Alluvial valley floor has the meaning set forth in 30 CFR... consistent with 40 CFR 1508.9. (k) Exploration has the meaning set forth in § 3480.0-5(a)(17) of this title... approved mining or exploration plan. This is the same as the Federal lease bond referred to in 30 CFR...

  2. 43 CFR 3400.0-5 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-5 Definitions. As used in this group: (a) Alluvial valley floor has the meaning set forth in 30 CFR... consistent with 40 CFR 1508.9. (k) Exploration has the meaning set forth in § 3480.0-5(a)(17) of this title... approved mining or exploration plan. This is the same as the Federal lease bond referred to in 30 CFR...

  3. 43 CFR 3400.0-5 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-5 Definitions. As used in this group: (a) Alluvial valley floor has the meaning set forth in 30 CFR... consistent with 40 CFR 1508.9. (k) Exploration has the meaning set forth in § 3480.0-5(a)(17) of this title... approved mining or exploration plan. This is the same as the Federal lease bond referred to in 30 CFR...

  4. 43 CFR 4700.0-5 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... HORSES AND BURROS General § 4700.0-5 Definitions. As used in this part, the term: (a) Act means the Act... Horse and Burro Act. (b) Authorized officer means any employee of the Bureau of Land Management to whom... means using a wild horse or burro because of its characteristics of wildness for direct or...

  5. Dielectric and electrical characteristics of La0.5Na0.5Ga0.5V0.5O3

    NASA Astrophysics Data System (ADS)

    Acharya, Truptimayee; Choudhary, R. N. P.

    2016-07-01

    La0.5Na0.5Ga0.5V0.5O3 (LNGVO) ceramic was prepared using a high-temperature solid-state reaction method. The structural phase, microstructure, dielectric, ferroelectric and optical properties of the material were systematically investigated. The preliminary structural analysis using x-ray diffraction (XRD) data shows the formation of the material in an orthorhombic crystal structure at room temperature. Detailed studies of dielectric and electrical properties have been carried out over a wide range of frequency (1 kHz-1 MHz) and temperature (25-450 °C) in order to elucidate the basic mechanism of the conduction and relaxation process. The dielectric characteristics show that the ceramic is a relaxor with strong diffuse phase transition and frequency dispersion. The nature of the variation of ac conductivity as a function of frequency obeys the universal power law, and confirms the existence of a hopping conduction mechanism in the material. The material also exhibits ferroelectricity at room temperature with a very low value of remnant polarization. The ionic conductivity and transport number of the ferroelectric ionic conductor were obtained with the standard experiment and calculation respectively. The material shows NTCR behavior similar to that of a semi-conductor. Similar behavior has also been observed in the study of I-V characteristics of the material.

  6. Ultrathin Hf0.5Zr0.5O2 Ferroelectric Films on Si.

    PubMed

    Chernikova, Anna; Kozodaev, Maksim; Markeev, Andrei; Negrov, Dmitrii; Spiridonov, Maksim; Zarubin, Sergei; Bak, Ohheum; Buragohain, Pratyush; Lu, Haidong; Suvorova, Elena; Gruverman, Alexei; Zenkevich, Andrei

    2016-03-23

    Because of their immense scalability and manufacturability potential, the HfO2-based ferroelectric films attract significant attention as strong candidates for application in ferroelectric memories and related electronic devices. Here, we report the ferroelectric behavior of ultrathin Hf0.5Zr0.5O2 films, with the thickness of just 2.5 nm, which makes them suitable for use in ferroelectric tunnel junctions, thereby further expanding the area of their practical application. Transmission electron microscopy and electron diffraction analysis of the films grown on highly doped Si substrates confirms formation of the fully crystalline non-centrosymmetric orthorhombic phase responsible for ferroelectricity in Hf0.5Zr0.5O2. Piezoresponse force microscopy and pulsed switching testing performed on the deposited top TiN electrodes provide further evidence of the ferroelectric behavior of the Hf0.5Zr0.5O2 films. The electronic band lineup at the top TiN/Hf0.5Zr0.5O2 interface and band bending at the adjacent n(+)-Si bottom layer attributed to the polarization charges in Hf0.5Zr0.5O2 have been determined using in situ X-ray photoelectron spectroscopy analysis. The obtained results represent a significant step toward the experimental implementation of Si-based ferroelectric tunnel junctions. PMID:26931409

  7. Ordering and disordering of doped Ga[sub 0. 5]In[sub 0. 5]P

    SciTech Connect

    Kurtz, S.R.; Olson, J.M.; Friedman, D.J.; Kibbler, A.E.; Asher, S. )

    1994-05-01

    The band gap of Ga[sub 0.5]In[sub 0.5]P is reported as a function of doping level and growth rate. The lowest band gaps are obtained for hole concentrations of about 2 x 10[sup 17] cm[sup [minus]3]. For samples doped p-type above 1 x 10[sup 18] cm[sup [minus]3], the band gap increases dramatically, regardless of growth rate. This effect is shown to be the result of disordering during growth rather than a change in the equilibrium surface structure with doping. The doping level dependence of the band gap of Ga[sub 0.5]In[sub 0.5]P samples grown at higher and lower growth rates differs for selenium and zinc doping even though the effects of high doping are the same for both dopants. 22 refs., 3 figs.

  8. 46 CFR 59.10-15 - Rivets and staybolts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service § 59.10-15 Rivets and staybolts. (a) It is not permitted to reinforce or build up by welding the heads of rivets or staybolts that have deteriorated. Such rivets or staybolts shall be replaced. The seal welding of...

  9. 46 CFR 59.10-15 - Rivets and staybolts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service § 59.10-15 Rivets and staybolts. (a) It is not permitted to reinforce or build up by welding the heads of rivets or staybolts that have deteriorated. Such rivets or staybolts shall be replaced. The seal welding of...

  10. 46 CFR 59.10-15 - Rivets and staybolts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service § 59.10-15 Rivets and staybolts. (a) It is not permitted to reinforce or build up by welding the heads of rivets or staybolts that have deteriorated. Such rivets or staybolts shall be replaced. The seal welding of...

  11. 33 CFR 67.10-15 - Approval of sound signals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Approval of sound signals. 67.10... Sound signals § 67.10-15 Approval of sound signals. (a) The Coast Guard approves a sound signal if: (1) It meets the requirements for sound signals in § 67.10-1 (a), (b), (c), (d), and (e) when...

  12. 33 CFR 67.10-15 - Approval of sound signals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Approval of sound signals. 67.10... Sound signals § 67.10-15 Approval of sound signals. (a) The Coast Guard approves a sound signal if: (1) It meets the requirements for sound signals in § 67.10-1 (a), (b), (c), (d), and (e) when...

  13. 33 CFR 67.10-15 - Approval of sound signals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Approval of sound signals. 67.10... Sound signals § 67.10-15 Approval of sound signals. (a) The Coast Guard approves a sound signal if: (1) It meets the requirements for sound signals in § 67.10-1 (a), (b), (c), (d), and (e) when...

  14. 33 CFR 67.10-15 - Approval of sound signals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Approval of sound signals. 67.10... Sound signals § 67.10-15 Approval of sound signals. (a) The Coast Guard approves a sound signal if: (1) It meets the requirements for sound signals in § 67.10-1 (a), (b), (c), (d), and (e) when...

  15. 33 CFR 67.10-15 - Approval of sound signals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Approval of sound signals. 67.10... Sound signals § 67.10-15 Approval of sound signals. (a) The Coast Guard approves a sound signal if: (1) It meets the requirements for sound signals in § 67.10-1 (a), (b), (c), (d), and (e) when...

  16. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... system shall be of watertight construction and bear a label plate denoting the power requirement of the..., USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine van... incombustible materials. (b) Lighting fixtures, if installed, shall be of an approved type equipped with...

  17. 46 CFR 58.10-15 - Gas turbine installations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MACHINERY AND RELATED SYSTEMS Internal Combustion Engine Installations § 58.10-15 Gas turbine installations... reference, see 46 CFR 58.03-1). (b) Materials. The materials used for gas turbine installations shall have... submitted to substantiate their suitability and safety for the service intended: (1) Combustion chamber....

  18. 46 CFR 58.10-15 - Gas turbine installations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MACHINERY AND RELATED SYSTEMS Internal Combustion Engine Installations § 58.10-15 Gas turbine installations... reference, see 46 CFR 58.03-1). (b) Materials. The materials used for gas turbine installations shall have... submitted to substantiate their suitability and safety for the service intended: (1) Combustion chamber....

  19. 46 CFR 58.10-15 - Gas turbine installations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MACHINERY AND RELATED SYSTEMS Internal Combustion Engine Installations § 58.10-15 Gas turbine installations... reference, see 46 CFR 58.03-1). (b) Materials. The materials used for gas turbine installations shall have... submitted to substantiate their suitability and safety for the service intended: (1) Combustion chamber....

  20. 46 CFR 58.10-15 - Gas turbine installations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MACHINERY AND RELATED SYSTEMS Internal Combustion Engine Installations § 58.10-15 Gas turbine installations... reference, see 46 CFR 58.03-1). (b) Materials. The materials used for gas turbine installations shall have... submitted to substantiate their suitability and safety for the service intended: (1) Combustion chamber....

  1. 46 CFR 58.10-15 - Gas turbine installations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MACHINERY AND RELATED SYSTEMS Internal Combustion Engine Installations § 58.10-15 Gas turbine installations... reference, see 46 CFR 58.03-1). (b) Materials. The materials used for gas turbine installations shall have... submitted to substantiate their suitability and safety for the service intended: (1) Combustion chamber....

  2. Magnetic properties of nanocrystalline Fe0.5Ni0.5 permalloy

    NASA Astrophysics Data System (ADS)

    De, D.; Majumdar, S.; Giri, S.

    2012-06-01

    We investigate magnetic properties of nanocrystalline Fe0.5Ni0.5 alloy embedded in the amorphous SiO2 host with volume fractions φ ≈ 10%. The static and dynamic aspects of the magnetic properties are investigated by investigating thermal and time dependence of low-field dc magnetization. Signature of strong interparticle interaction is noted in the magnetization results. The relaxation process at low temperature is fitted with stretched exponential function, displaying coexistence of ferromagnetic and glassy magnetic components.

  3. Magnetization reversal in the orthochromite Y0 . 5 Gd0.5 CrO3

    NASA Astrophysics Data System (ADS)

    Duran, Alejandro; Escudero, Roberto; Escamilla, Raul; Morales, Fransisco; Verdin, Eduardo

    Complex oxide of transition metal with perovskite structure represent fascinating playground for basic solid state research: new electronics and exotic ground states emerge via the competing interplay like spin, orbital, charge as well as lattice degree of freedom. Accordingly, orthochromites are not exception to the rule. In these compounds have been found ferroelectric polarization, spin reorientation transition along with the characteristic behavior known as; magnetization reversal (MR) consisting that a characteristic temperature, T*, the system becomes diamagnetic. In this work, the magnetic behavior of the equimolar Y0.5Gd0.5CrO3 composition was studied. Negative magnetization was observed at T*~70 K in FC mode, and applied field of 100 Oe. The characteristic hysteresis loop in the M-H graph of the pristine sample disappears for a wide range of temperature below of TN, and the characteristic spin reorientation is shifted from 14 K in GdCrO3 to 5 K for Y0.5Gd0.5CrO3. The negative magnetization is explained according the model that take into account the anisotropic and antisymmetric exchange interaction between Gd +3 - Cr +3 sublattice. A.D. and R.E. thanks to grants by DGAPA-PAPIIT, IN103213 and IN 106014 respectively.

  4. Magnetoresistance of La0.5Sr0.5MnO3 nanoparticle compact

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Hong; Ji, Tian-Hao; Wang, Yi-Qian; Chen, Xin; Li, Run-Wei; Cai, Jian-Wang; Sun, Ji-Rong; Shen, Bao-Gen; Yan, Chun-Hua

    2000-05-01

    Magnetization, resistance, and current-voltage (I-V) measurements have been performed in La0.5Sr0.5MnO3 compact prepared by pressing sol-gel nanoparticles (46 nm) at 723 K with a high pressure (4 GPa). The pressed compound orders ferromagnetically at 340 K (TC) and has a substantial drop in the thermomagnetic curve below 158 K (TDP). After undergoing a metal-to-semiconductor transition at 140 K (TMS), the compound reenters into a strong semiconducting state below 60 K, demonstrating a charge localized behavior induced by the small grain rather than the magnetic disorder which is related with the frozen spin clusters below TDP. Instead of showing a feature near TMS, the magnetoresistance (MR) ratio increases almost linearly with decreasing temperature. The large low field MR corresponding to the sharp rise of magnetization is obtained at 5 K and, evidenced as the spin polarized intergrain tunneling (SPIT) effect by the nolinear I-V curve. Although La0.5Sr0.5MnO3 has a relatively high TC, the SPIT MR decays rapidly from 17.6% (5 K, 0.3 T) to 7.6% (150 K, 0.3 T), indicating that if trying to put the low field sensitivity of SPIT MR into application at room temperature, the selected compound having a higher TC seems to be a prerequisite.

  5. Ellipsometric study of Si(0.5)Ge(0.5)/Si strained-layer superlattices

    NASA Technical Reports Server (NTRS)

    Sieg, R. M.; Alterovitz, S. A.; Croke, E. T.; Harrell, M. J.

    1993-01-01

    An ellipsometric study of two Si(0.5)Ge(0.5)/Si strained-layer super lattices grown by MBE at low temperature (500 C) is presented, and results are compared with x ray diffraction (XRD) estimates. Excellent agreement is obtained between target values, XRD, and ellipsometry when one of two available Si(x)Ge(1-x) databases is used. It is shown that ellipsometry can be used to nondestructively determine the number of superlattice periods, layer thicknesses, Si(x)Ge(1-x) composition, and oxide thickness without resorting to additional sources of information. It was also noted that we do not observe any strain effect on the E(sub 1) critical point.

  6. Ellipsometric study of Si(0.5)Ge(0.5)/Si strained-layer superlattices

    NASA Technical Reports Server (NTRS)

    Sieg, R. M.; Alterovitz, S. A.; Croke, E. T.; Harrell, M. J.

    1993-01-01

    We present an ellipsometric study of two Si(0.5)Ge(0.5)/Si strained-layer superlattices grown by MBE at low temperature (500 C), and compare our results with X-ray diffraction (XRD) estimates. Excellent agreement is obtained between target values, XRD, and ellipsometry when one of two available Si(x)Ge(1-x) databases is used. We show that ellipsometry can be used to nondestructively determine the number of superlattice periods, layer thicknesses, Si(x)Ge(1-x) composition, and oxide thickness without resorting to additional sources of information. We also note that we do not observe any strain effect on the E1 critical point.

  7. Kinetics of the chemical oxidation of (5,10,15,20-tetraphenyl-21H,23H-porphinato)(chloro)(aqua)iridium(III)

    NASA Astrophysics Data System (ADS)

    Tyulyaeva, E. Yu.; Bichan, N. G.; Mozhzhukhina, E. G.; Lomova, T. N.

    2016-01-01

    The oxidation of (Cl)(H2O)IrTPP with atmospheric oxygen in the presence of concentrated H2SO4 accompanied by coordination of molecular O2 and substitution of axial ligands was studied spectrophotometrically. In 16.785-18.09 MH2SO4 at 298-318 K, (Cl)(H2O)IrTPP experienced two single-electron oxidations in sequence: with an increase in the oxidation state of the iridium cation and with formation of the π-radical cation form (HSO4)IrIVTPP•+ oxidized at the aromatic ligand ( k 298 = 7.2 × 10-6 mol-1 L s-1). Referring to the literature data on the oxidation of (Cl)(H2O)IrTPP in AcOH and CF3COOH, it was shown that the medium acidity and the nature of the axial ligands affect the electron removal site in the chemical oxidation of (Cl)(H2O)IrTPP with atmospheric oxygen in proton-donor solvents.

  8. (2,3,5,6-Tetra­fluoro­phenolato-κO)(5,10,15,20-tetra­phenyl­porphyrinato)iron(III)

    PubMed Central

    Xu, Nan; Powell, Douglas R.; Richter-Addo, George B.

    2013-01-01

    The title compound, [Fe(C44H28N4)(C6HF4O)], is a porphyrin complex with iron(III) in fivefold coordination with a tetra­fluoro­phenolate group as the axial ligand. The Fe atom and the phenolate ligand are disordered across the porphyrin ring with the two phenolates appearing to be roughly related by a center of symmetry. The occupancies of the two phenolate groups refined to 0.788 (3) for the major component and 0.212 (3) for the minor component. The structure shows extraordinary Fe displacements of 0.488 (4) (major) and 0.673 (4) Å (minor) from the 24-atom mean plane of the porphyrin. The Fe—Np distances range from 2.063 (4) to 2.187 (6) Å and the Fe—O distances are 1.903 (5) Å for major component and 1.87 (2) Å for minor component. The four phenyl groups attached to the porphyrin ring form dihedral angles of 63.4 (4), 49.6 (4), 62.4 (4), and 63.3 (4)° (in increasing numerical order) with the three nearest C atoms of the porphyrin ring. The major and minor component phenolate groups form dihedral angles of 24.9 (4)° and 24.8 (4)°, respectively, with the four porphyrin N atoms. The Fe⋯Fe distance between the two iron(III) atoms of adjacent porphyrin mol­ecules is 6.677 (3) Å. No close inter­molecular inter­action was observed. The crystal studied was twinned by inversion, with a major–minor component ratio of 0.53 (3):0.47 (3). PMID:24098188

  9. Tri-μ-oxido-bis­[(5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)niobium(V)

    PubMed Central

    Soury, Raoudha; Belkhiria, Mohamed Salah; Daran, Jean-Claude; Nasri, Habib

    2011-01-01

    In the title dinuclear NbV compound, [Nb2(C44H28N4)2O3], each Nb atom is seven-coordinated with three bridging O atoms and four N atoms from a chelating tetra­phenyl­porphyrinate anion. The Nb—O bond lengths range from 1.757 (6) to 2.331 (6) Å, and the average (niobium–pyrrole N atom) distance is 2.239 Å. In the dinuclear mol­ecule, the Nb⋯Nb separation is 2.8200 (8) Å, and the dihedral angle between the two porphyrinate mean planes is 5.4 (1)°. Weak inter­molecular C—H⋯π inter­actions are present in the crystal structure. PMID:21836860

  10. 3-NO2-5,10,15-triarylcorrolato-Cu as a versatile platform for synthesis of novel 3-functionalized corrole derivatives

    PubMed Central

    Stefanelli, M.; Mancini, M.; Raggio, M.; Fronczeck, F. R.; McCandless, G. T.; Smith, K. M.; Paolesse, R.

    2014-01-01

    β–Nitrocorrole derivatives are potentially valuable platforms for the preparation of a wide range of more elaborated corrole derivatives possessing unique chemical functionalities and electronic properties. Here we report our results on the chemical manipulation of a copper 3-NO2-triarylcorrolate using different organic reactions, all involving the reduction of –NO2 to –NH2 at an early stage, followed by further transformations. By way of a β-acylated copper corrolate, a novel corrole derivative bearing an alkyl azide group on the peripheral positions was obtained and exploited in the Huisgen 1,3-dipolar cycloaddition. PMID:25005049

  11. Hydrogen-induced phase separation in amorphous Cu0.5Ti0.5 alloys. I. Room-temperature experiments

    NASA Astrophysics Data System (ADS)

    Rodmacq, B.; Maret, M.; Laugier, J.; Billard, L.; Chamberod, A.

    1988-07-01

    The influence of hydrogen on the structure of an amorphous Cu0.5Ti0.5 alloy has been studied by means of x-ray and neutron scattering. These experiments include large-angle x-ray and neutron scattering and small-angle neutron scattering with hydrogen-deuterium substitution. The results indicate that large hydrogen contents (hydrogen-to-metal ratio of 0.84) induce a phase separation into Cu and TiHx regions on a scale of about 10-15 Å. Experiments on samples loaded with hydrogen by electrolysis or from the gas phase show that such a phase separation does not depend on the method of hydrogen loading. The results of a computer simulation with nearest-neighbor Cu-Ti permutations reproduce the main features of the diffraction data and confirm the large change of chemical ordering between Cu and Ti atoms upon hydrogen absorption.

  12. Isosbestic Point and Magnetoresistance Components in Ho_{0.5} Lu_{0.5} B_{12}

    NASA Astrophysics Data System (ADS)

    Khoroshilov, A. L.; Azarevich, A. N.; Bogach, A. V.; Glushkov, V. V.; Demishev, S. V.; Krasnorussky, V. N.; Voronov, V. V.; Shitsevalova, N. Yu; Filippov, V. B.; Gabani, S.; Flachbart, K.; Sluchanko, N. E.

    2016-01-01

    We present the results of precise magnetoresistance (MR) measurements of an antiferromagnetic cage-glass solid solution Ho_{0.5} Lu_{0.5} B_{12} in magnetic fields up to 80 kOe and at temperatures between 1.9 and 100 K. The analysis of results allows to separate the positive and negative contributions to MR. The dominant MR-term was found to be the high field positive contribution Δ ρ /ρ _{(m+)} =μ _D^2 H^2 which is caused by the drift mobility μ _D of charge carriers. It was also shown that the negative MR observed at temperatures T ≤ 10 K may be described by the well-known relation between MR and local magnetization Δ ρ /ρ _{(-)} =M_{loc}^2 obtained by Yosida in the framework of s-d exchange model. We discuss as well the scattering of charge carriers on antiferromagnetic nanosize domains of Ho^{3+} ions with effective magnetic moments 3.5-5.5 μ _B as the mechanism responsible for the appearance of the negative MR component.

  13. Magnetisation configuration at the interface of Fe_0.5Mn_0.5/Co(111)

    NASA Astrophysics Data System (ADS)

    Ujfalussy, Balazs; Schultess, T. C.; Stocks, G. M.; Canning, A.

    2002-03-01

    The microscopic understanding of the interface of a ferromagnet and an antiferromagnet is of fundamental importance in the problem of exchange bias. Of particular interest is the interface between Fe_0.5Mn_0.5/Co(111) however, it is rather difficult to study it experimentally. We performed an ab-initio spin-dynamics calculation to determine the magnetization configuration of this interface. We find that the magnetization changes from a 3Q-like state to a 1Q-like state which is perpendicular to the magnetization of the Co at the interface. We comment on the range of the interaction and possible mechanism of exchange bias. This work was supported by the Division of Materials Sciences and Engineering, and by the Director, Office of Advanced Scientific Computing Research, Division of Mathematical Information and Computational Sciences Division, of the U.S. Department of Energy, under contract number DE-AC03-76SF00098 and subcontract DE-AC05-00OR22725 with UT-Battelle LLC.

  14. Influence of electron beam irradiation on the structural, electrical and thermal properties of Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 manganites

    NASA Astrophysics Data System (ADS)

    Nagaraja, B. S.; Rao, Ashok; Babu, P. D.; Sanjeev, Ganesh; Okram, G. S.

    2016-01-01

    We present systematic studies on the effect of electron beam irradiation on structural, electrical and thermal properties of Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 manganites. The XRD patterns and Rietveld analysis show that the samples remain single phased even after they undergo electron beam irradiation. Both the series of the samples Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 show insulating trends in their temperature dependent electrical resistivity, ρ(T) behavior. The resistivity data for both the series of samples (pristine as well as irradiated) indicate that the small polaron hopping model is valid in high temperature region; on contrary, variable range hopping model governs the low temperature regime. Magnetic studies demonstrate that the Neel temperatures of pristine and irradiated samples of Gd0.5Sr0.5MnO3 and Dy0.5Sr0.5MnO3 do not change appreciably when they are subjected to irradiation. Thermo-electrical power is observed to increase with irradiation in Gd0.5Sr0.5MnO3 samples, whereas for Dy0.5Sr0.5MnO3 samples a decrease in thermo-electric power is seen when the samples are irradiated.

  15. 16 CFR 0.5 - Laws authorizing monetary claims.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Laws authorizing monetary claims. 0.5 Section 0.5 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.5 Laws authorizing monetary claims. The Commission is authorized to entertain monetary...

  16. Self-assembled In0.5Ga0.5As quantum dots on GaP

    NASA Astrophysics Data System (ADS)

    Song, Yuncheng; Simmonds, Paul J.; Lee, Minjoo Larry

    2010-11-01

    We demonstrate the growth and luminescence of coherently strained In0.5Ga0.5As self-assembled quantum dots on GaP. Cross-sectional and planar-view transmission electron microscopy confirmed the dislocation-free nature of the In0.5Ga0.5As quantum dots and GaP cap layers. Intense photoluminescence from the quantum dots was measured at 80 K and was visible to the unaided eye in ambient lighting. The photoluminescence results show that emission energy can be controlled by varying the In0.5Ga0.5As deposition thickness. In combination with recent advances in the growth of GaP on Si, the In0.5Ga0.5As quantum dots demonstrated here could enable monolithic optoelectronic integration on Si.

  17. Ni-doped La0.5Sr0.5TiO3 nanofibers: Fabrication and intrinsic ferromagnetism

    NASA Astrophysics Data System (ADS)

    Ponhan, Wichaid; Amornkitbamrung, Vittaya; Maensiri, Santi

    2016-06-01

    We report room-temperature ferromagnetism in ∼104–133 nm nanofibers of La0.5Sr0.5Ti1‑ x Ni x O3 (0.02 ≤ x ≤ 0.05). As-spun nanofibers of La0.5Sr0.5Ti1‑ x Ni x O3 are fabricated by an electrospinning technique. Nanofibers of the as spun and calcined La0.5Sr0.5Ti1‑ x Ni x O3 samples are characterized using X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), X-ray photoelectron microscopy (XPS), X-ray absorption near edge structure (XANES) determination, and vibrating sample magnetometry (VSM). The results of XRD analysis and TEM together with selected electron diffraction (SEAD) analysis indicate that La0.5Sr0.5Ti1‑ x Ni x O3 nanofibers have a cubic perovskite structure with no secondary phase. The as-spun samples are paramagnetic, whereas the La0.5Sr0.5Ti1‑ x Ni x O3 samples are ferromagnetic having specific magnetizations of 0.098–0.484 emu/g at 10 kOe. The XPS spectra show that there are some oxygen vacancies in the nanofibers, which its may play an important role in inducing room-temperature ferromagnetism in La0.5Sr0.5Ti1‑ x Ni x O3 nanofibers. XANES spectra show that most of the Ni ions in La0.5Sr0.5Ti1‑ x Ni x O3 nanofibers are in the Ni2+ state mixed with some Ni metal. The finding of room temperature ferromagnetism in this nanofibrous structure of the La0.5Sr0.5Ti1‑ x Ni x O3 system is of interest in research on diluted magnetic oxides.

  18. Near-infrared emitting CdTe0.5Se0.5/Cd0.5Zn0.5S quantum dots: synthesis and bright luminescence

    PubMed Central

    2012-01-01

    We present how CdTe0.5Se0.5 cores can be coated with Cd0.5Zn0.5S shells at relatively low temperature (around 200°C) via facile synthesis using organic ammine ligands. The cores were firstly fabricated via a less toxic procedure using CdO, trioctylphosphine (TOP), Se, Te, and trioctylamine. The cores with small sizes (3.2-3.5 nm) revealed green and yellow photoluminescence (PL) and spherical morphologies. Hydrophobic core/shell CdTe0.5Se0.5/Cd0.5Zn0.5S quantum dots (QDs) with tunable PL between green and near-infrared (a maximum PL peak wavelength of 735 nm) were then created through a facile shell coating procedure using trioctylphosphine selenium with cadmium and zinc acetate. The QDs exhibited high PL efficiencies up to 50% because of the formation of a protective Cd0.5Zn0.5S shell on the CdTe0.5Se0.5 core, even though the PL efficiency of the cores is low (≤1%). Namely, the slow growth process of the shell plays an important role for getting high PL efficiencies. The properties of the QDs are largely determined by the properties of CdTe0.5Se0.5 cores and shells preparation conditions such as reaction temperature and time. The core/shell QDs exhibited a small size diameter. For example, the average diameter of the QDs with a PL peak wavelength of 735 nm is 6.1 nm. Small size and tunable bright PL makes the QDs utilizable as bioprobes because the size of QD-based bioprobes is considered as the major limitation for their broad applications in biological imaging. PMID:23130948

  19. RF tests of the beta - 0.5 five cell TRASCO cavities

    SciTech Connect

    A. Bosotti; Carlo Pagani; P. Pierini; J.P. Charrier; B. Visentin; Gianluigi Ciovati; Peter Kneisel

    2004-07-01

    Two complete 5 cell superconducting cavities at {beta} = 0.5 have been fabricated in the TRASCO INFN program. The cavities have been designed to minimize peak electric and magnetic fields, with a goal of 8.5 MV/m of accelerating gradient, at a Q > 5 10{sup 9}. The cavities have been tested in vertical cryostats at TJNAF and Saclay and the results are summarized here.

  20. Non-random cation distribution in hexagonal Al 0.5Ga 0.5PO 4

    NASA Astrophysics Data System (ADS)

    Kulshreshtha, S. K.; Jayakumar, O. D.; Sudarsan, V.

    2010-05-01

    Based on powder X-ray diffraction and 31P Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) investigations of mixed phosphate Al 0.5Ga 0.5PO 4, prepared by co-precipitation method followed by annealing at 900 °C for 24 h, it is shown that Al 0.5Ga 0.5PO 4 phase crystallizes in hexagonal form with lattice parameter a=0.491(2) and c=1.106(4) nm. This hexagonal phase of Al 0.5Ga 0.5PO 4 is similar to that of pure GaPO 4. The 31P MAS NMR spectrum of the mixed phosphate sample consists of five peaks with systematic variation of their chemical shift values and is arising due to existence of P structural units having varying number of the Al 3+/Ga 3+ cations as the next nearest neighbors in the solid solution. Based on the intensity analysis of the component NMR spectra of Al 0.5Ga 0.5PO 4, it is inferred that the distribution of Al 3+ and Ga 3+ cations is non-random for the hexagonal Al 0.5Ga 0.5PO 4 sample although XRD patterns showed a well-defined solid solution formation.

  1. Impact of mechanical stress on ferroelectricity in (Hf0.5Zr0.5)O2 thin films

    NASA Astrophysics Data System (ADS)

    Shiraishi, Takahisa; Katayama, Kiliha; Yokouchi, Tatsuhiko; Shimizu, Takao; Oikawa, Takahiro; Sakata, Osami; Uchida, Hiroshi; Imai, Yasuhiko; Kiguchi, Takanori; Konno, Toyohiko J.; Funakubo, Hiroshi

    2016-06-01

    To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf0.5Zr0.5)O2 thin films were deposited on (111)Pt-coated SiO2, Si, and CaF2 substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10-6/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf0.5Zr0.5)O2 thin films deposited on SiO2 and Si substrates were under in-plane tensile strain and that their volume fraction of monoclinic phase decreased as this strain increased. In contrast, films deposited on CaF2 substrates were under in-plane compressive strain, and their volume fraction of monoclinic phase was the largest among the three kinds of substrates. The maximum remanent polarization of 9.3 μC/cm2 was observed for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2, while ferroelectricity was barely observable for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2/CaF2. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf0.5Zr0.5)O2 thin films.

  2. Synthesis and luminescence characterization of Sr(0.5)Ca(0.5)TiO3:Sm(3+) phosphor.

    PubMed

    Vidyadharan, Viji; Remya, Mohan P; Gopi, Subhash; Thomas, Sunil; Joseph, Cyriac; Unnikrishnan, N V; Biju, P R

    2015-11-01

    The spectroscopic properties of trivalent samarium doped Sr0.5Ca0.5TiO3 perovskite phosphor material (Sr0.5Ca0.5TiO3:xSm(3+), x=0.05, 0.1, 0.5, 1, 1.5) synthesized by the solid state method have been studied. The X-Ray Diffraction profile confirms the orthorhombic perovskite Sr0.5Ca0.5TiO3 structure of the prepared samples. The SEM study reveals the surface morphology. The Judd-Ofelt intensity parameters were calculated for 0.5 wt% Sm(3+) doped Sr0.5Ca0.5TiO3. Transition probabilities, branching ratios and radiative lifetime were evaluated by using Judd-Ofelt analysis. The emission spectra under 405 nm excitation shows five emission peaks at 564 nm, 599 nm, 645 nm, 707 nm and 776 nm corresponding to the transitions (4)G5/2→(6)Hj (j=5/2, 7/2, 9/2, 11/2 and 13/2) respectively. The higher values of branching ratio and stimulated emission cross-section for (4)G5/2→(6)H7/2 transition of Sr0.5Ca0.5TiO3:0.5 wt% Sm(3+) shows its suitability in the field of visible lasers and optical fiber amplifiers. The experimental lifetimes of Sm(3+) doped samples were estimated using the decay curves corresponding to (4)G5/2→(6)H7/2 transition upon 405 nm excitation. Concentration dependence on emission intensity and experimental lifetime were also studied. From the CIE diagram we can see that as the concentration of Sm(3+) ions increases from 0.05 wt% to 1.5 wt% the CIE color co-ordinates changes from greenish yellow to yellowish orange. PMID:26057096

  3. Ga0.5In0.5P Barrier Layer for Wet Oxidation of AlAs

    NASA Astrophysics Data System (ADS)

    Lee, Shih-Chang; Lee, Wei-I

    2000-05-01

    We study the stability of Ga0.5In0.5P and Al0.4Ga0.6As barrier layers for wet thermal oxidation of AlAs on GaAs. Samples with a Ga0.5In0.5P or Al0.4Ga0.6As barrier layer are oxidized in a water vapor environment under various oxidation conditions. The results of photoluminescence and secondary-ion mass spectrometry (SIMS) depth profile measurements indicate that the Ga0.5In0.5P barrier layer is more stable than the Al0.4Ga0.6As layer at higher oxidation temperatures and longer periods of oxidation time.

  4. Structure, phase evolution, and microwave dielectric properties of (Ag0.5Bi0.5)(Mo0.5W0.5)O4 ceramic with ultralow sintering temperature.

    PubMed

    Zhou, Di; Li, Wen-Bo; Guo, Jing; Pang, Li-Xia; Qi, Ze-Ming; Shao, Tao; Xie, Hui-Dong; Yue, Zhen-Xing; Yao, Xi

    2014-06-01

    In the present work, the microwave dielectric ceramic (Ag0.5Bi0.5)(Mo0.5W0.5)O4 was prepared by using the solid-state reaction method. (Ag0.5Bi0.5)(Mo0.5W0.5)O4 was found to crystallize in the scheelite structure, in which Ag(+) and Bi(3+) occupy the A site randomly with 8-coordination while Mo(6+) and W(6+) occupy the B site with 4-coordination, at a sintering temperature above 500 °C, with lattice parameters a = b = 5.29469(2) Å and c = 11.62114(0) Å, space group I4(1)/a (No. 88), and acceptable Rp = 9.38, Rwp = 11.2, and Rexp = 5.86. High-performance microwave dielectric properties, with permittivity ∼26.3, Qf value ∼10,000 GHz, and temperature coefficient ∼+20 ppm/°C, were obtained in the sample sintered at 580 °C. Its chemical compatibility with aluminum at its sintering temperature was revealed and confirmed by both X-ray and energy dispersive spectrometer analysis. This ceramic could be a good candidate for ultralow-temperature cofired ceramics. PMID:24848200

  5. 16 CFR 0.5 - Laws authorizing monetary claims.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Laws authorizing monetary claims. 0.5... ORGANIZATION § 0.5 Laws authorizing monetary claims. The Commission is authorized to entertain monetary claims..., unless the adjudicative officer finds that the party has committed a willful violation of law...

  6. Thermochromic effect at room temperature of Sm0.5Ca0.5MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Boileau, A.; Capon, F.; Barrat, S.; Laffez, P.; Pierson, J. F.

    2012-06-01

    Sm0.5Ca0.5MnO3 thermochromic thin films were synthesized using dc reactive magnetron co-sputtering and subsequent annealing in air. The film structure was studied by x-ray diffraction analysis. To validate the thermochromic potentiality of Sm0.5Ca0.5MnO3, electrical resistivity and infrared transmittance spectra were recorded for temperatures ranging from 77 K to 420 K. The temperature dependence of the optical band gap was estimated in the near infrared range. Upon heating, the optical transmission decreases in the infrared domain showing a thermochromic effect over a wide wavelength range at room temperature.

  7. Fully gapped superconductivity in In-doped topological crystalline insulator Pb0.5Sn0.5Te

    NASA Astrophysics Data System (ADS)

    Du, Guan; Du, Zengyi; Fang, Delong; Yang, Huan; Zhong, R. D.; Schneeloch, J.; Gu, G. D.; Wen, Hai-Hu

    2015-07-01

    Superconductors derived from topological insulators and topological crystalline insulators by chemical doping have long been considered to be candidates as topological superconductors. Pb0.5Sn0.5Te is a topological crystalline insulator with mirror symmetry protected surface states on (001)-, (011)-, and (111)-oriented surfaces. The superconductor (Pb0.5Sn0.5 )0.7In0.3Te is produced by In doping in Pb0.5Sn0.5Te , and is thought to be a topological superconductor. Here we report scanning tunneling spectroscopy measurements of the superconducting state as well as the superconducting energy gap in (Pb0.5Sn0.5 )0.7In0.3Te on a (001)-oriented surface. The spectrum can be well fitted by an anisotropic s -wave gap function of Δ (θ )=0.72 +0.18 cos4 θ meV using Dynes model. The results show that the superconductor seems to be a fully gapped one without any in-gap states, in contradiction with the expectation of a topological superconductor.

  8. Fabrication and properties of Mn 0.5Zn 0.5Fe 2O 4 nanofibers

    NASA Astrophysics Data System (ADS)

    Li, Qiailing; Wang, Wenting

    2010-08-01

    Zn-doped α-FeOOH nanofiber was synthesized by coprecipitation method. Then the α-FeOOH was enwraped by the complex of the Mn 2+ and citric acid. The morphology of α-FeOOH did not transform after the calcination process and Mn 0.5Zn 0.5Fe 2O 4 nanofiber was successfully prepared. The phase, morphology, particle diameter and the magnetic properties of samples were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The results indicated that Mn 0.5Zn 0.5Fe 2O 4 nanofibers with an aspect ratio over 40 and a diameter of 20 nm were prepared. Compared with the amorphous Mn 0.5Zn 0.5Fe 2O 4, the anisotropy of the Mn 0.5Zn 0.5Fe 2O 4 nanofiber increased, resulting in the higher coercivity and magnetization of the obtained sample. With an increase in the calcination temperature, the diameter and the saturation magnetization of the sample increased, while the aspect ratio and coercivity decreased. The coercivity of the sample obtained at 700 °C was maximal (up to 185.4 Oe). The saturation magnetization of the sample obtained at 900 °C was maximal (up to 65.3 emu/g). The use of citric acid method prevented the presence of Mn(OH) 2, resulting in the decrease of the calcination temperature.

  9. Preparation and Thermoelectric Properties of the Skutterudite-Related Phase Ru(0.5)Pd(0.5)Sb3

    NASA Technical Reports Server (NTRS)

    Caillat, T.; Kulleck, J.; Borshchevsky, A.; Fleurial, J.-P.

    1996-01-01

    A new skutterudite phase Ru(0.5)Pd(0.5)Sb3 was prepared. This new phase adds to a large number of already known materials with the skutterudite structure which have shown good potential for thermoelectric applications. Single phase, polycrystalline samples were prepared and characterized by x-ray analysis, electron probe microanalysis, density, sound velocity, thermal-expansion coefficient, and differential thermal analysis measurements. Ru(0.5)Pd(0.5)Sb3 has a cubic lattice, space group Im3 (T(sup 5, sub h)), with a = 9.298 A and decomposes at about 920 K. The Seebeck coefficient, the electrical resistivity, the Hall effect, and the thermal conductivity were measured on hot-pressed samples over a wide range of temperatures. Preliminary results show that Ru(0.5)Pd(0.5)Sb3 behaves as a heavily doped semiconductor with an estimated band gap of about 0.6 eV. The lattice thermal conductivity of Ru(0.5)Pd(0.5)Sb3 is substantially lower than that of the binary isostructural compounds CoSb3 and IrSb3. The unusually low thermal conductivity might be explained by additional hole and charge transfer phonon scattering in this material. The potential of this material for thermoelectric applications is discussed.

  10. Fully gapped superconductivity in In-doped topological crystalline insulator Pb0.5Sn0.5Te

    DOE PAGESBeta

    Du, Guan; Gu, G. D.; Du, Zengyi; Fang, Delong; Yang, Huan; Zhong, R. D.; Schneeloch, J.; Wen, Hai -Hu

    2015-07-27

    In this study, superconductors derived from topological insulators and topological crystalline insulators by chemical doping have long been considered to be candidates as topological superconductors. Pb0.5Sn0.5Te is a topological crystalline insulator with mirror symmetry protected surface states on (001)-, (011)-, and (111)-oriented surfaces. The superconductor (Pb0.5Sn0.5)0.7In0.3Te is produced by In doping in Pb0.5Sn0.5Te, and is thought to be a topological superconductor. Here we report scanning tunneling spectroscopy measurements of the superconducting state as well as the superconducting energy gap in (Pb0.5Sn0.5)0.7In0.3Te on a (001)-oriented surface. The spectrum can be well fitted by an anisotropic s-wave gap function of Δ =more » 0.72 + 0.18cos4θ meV using Dynes model. The results show that the superconductor seems to be a fully gapped one without any in-gap states, in contradiction with the expectation of a topological superconductor.« less

  11. 46 CFR 31.10-15 - Inspection for certification-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Inspection for certification-TB/ALL. 31.10-15 Section 31.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Inspections § 31.10-15 Inspection for certification—TB/ALL. (a) After receiving an application for...

  12. 46 CFR 31.10-15 - Inspection for certification-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Inspection for certification-TB/ALL. 31.10-15 Section 31.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Inspections § 31.10-15 Inspection for certification—TB/ALL. (a) After receiving an application for...

  13. 46 CFR 31.10-15 - Inspection for certification-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Inspection for certification-TB/ALL. 31.10-15 Section 31.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Inspections § 31.10-15 Inspection for certification—TB/ALL. (a) After receiving an application for...

  14. 46 CFR 31.10-15 - Inspection for certification-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Inspection for certification-TB/ALL. 31.10-15 Section 31.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Inspections § 31.10-15 Inspection for certification—TB/ALL. (a) After receiving an application for...

  15. 46 CFR 31.10-15 - Inspection for certification-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Inspection for certification-TB/ALL. 31.10-15 Section 31.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Inspections § 31.10-15 Inspection for certification—TB/ALL. (a) After receiving an application for...

  16. 46 CFR 38.10-15 - Safety relief valves-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Piping, Valves, Fittings, and Accessory Equipment § 38.10-15 Safety relief valves—TB/ALL. (a) Each tank shall be...

  17. 46 CFR 38.10-15 - Safety relief valves-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15..., Fittings, and Accessory Equipment § 38.10-15 Safety relief valves—TB/ALL. (a) Each tank shall be fitted with or (subject to approval by the Commandant) connected to one or more safety relief valves...

  18. Structure and dielectric dispersion in cubic-like 0.5K0.5Na0.5NbO3-0.5Na1/2Bi1/2TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Liu, Laijun; Knapp, Michael; Schmitt, Ljubomira Ana; Ehrenberg, Helmut; Fang, Liang; Fuess, Hartmut; Hoelzel, Markus; Hinterstein, Manuel

    2016-05-01

    The nature of the cubic-like state in the lead-free piezoelectric ceramics 0.5K0.5Na0.5NbO3-0.5Na1/2Bi1/2TiO3 (KNN-50BNT) has been examined in detail by synchrotron x-ray diffraction (SD), selected-area electron diffraction (SAED), neutron diffraction (ND), and temperature-dependent dielectric characterization. The SD pattern of KNN-50BNT presents a pure perovskite structure with pseudocubic symmetry. However, superlattice reflections were observed by SAED and completely indexed by tetragonal symmetry with P4bm space group in ND pattern. The relaxor behavior of KNN-50BNT is compared with Pb-based and Ba-based relaxors and discussed in the framework of the Vogel-Fulcher law and the new glass model. The KNN-50BNT ceramic exhibits the strongest dielectric dispersion among them.

  19. Phase formation, structure and dielectric properties of ceramics (Na0.5Bi0.5)TiO3-(K0.5Na0.5)NbO3-BiFeO3

    NASA Astrophysics Data System (ADS)

    Kaleva, G. M.; Mosunov, A. V.; Sadovskaya, N. V.; Politova, E. D.; Stefanovich, S. Yu.

    2016-04-01

    Influence of BiFeO3 (BF) on phase formation, unit cell parameters, microstructure, dielectric and ferroelectric properties of solid solutions close to the morphotropic phase boundary in the (Na0.5Bi0.5)TiO3-(K0.5Na0.5)NbO3 system additionally modified by the low-melting KCl additives has been studied. The formation of pure perovskite structure samples decrease in the unit cell parameters and increase in the TC value stimulated by the BF addition have been revealed. It was proved that modification of compositions by small amounts of the BF and KCl additives leads to improvement of dielectric parameters.

  20. Proton conduction and chemical stability of (La{sub 0.5}Sr{sub 0.5})(Mg{sub 0.5+y}Nb{sub 0.5-y})O{sub 3-{delta}}

    SciTech Connect

    Kawasaki, Yuya; Okada, Sachio; Ito, Naoki; Matsumoto, Hiroshige Ishihara, Tatsumi

    2009-02-04

    Electrical conduction properties of complex perovskite-type oxides in the (La{sub 0.5}Sr{sub 0.5})(Mg{sub 0.5+y}Nb{sub 0.5-y})O{sub 3-{delta}} (y = 0.02-0.06) series at intermediate-high temperatures were investigated; introduction of protons by hydration of oxide-ion vacancies was expected by increasing the Mg/Nb ratio from unity. The conductivity depended on y and a maximum conductivity was obtained at y = 0.04: {sigma} = 4.9 x 10{sup -6} S cm{sup -1} at 400 deg. C in wet H{sub 2} atmospheres. From electromotive force measurements of hydrogen and water vapor concentration cells, electrical conduction in wet H{sub 2} atmospheres can be attributed to ionic conduction, and proton conduction is dominant below 700 deg. C. Unlike other perovskite-type proton conductors, (La{sub 0.5}Sr{sub 0.5})(Mg{sub 0.54}Nb{sub 0.46})O{sub 3-{delta}} was stable in CO{sub 2} atmospheres even in the low-intermediate temperature region due to dilution of reactive strontium by lanthanum.

  1. Enhanced electrostricitive properties and thermal endurance of textured (Bi0.5Na0.5)TiO3-BaTiO3-(K0.5Na0.5)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Ye, Chenggen; Shen, Bo; Zhai, Jiwei

    2013-08-01

    Textured 0.92(Bi0.5Na0.5)TiO3-0.06BaTiO3-0.02(K0.5Na0.5)NbO3 (BNT-BT-KNN) ceramics have been produced by tape casting with pure-phase (Bi0.5Na0.5)TiO3 templates. Through the approach of texture construction, enhanced electrostrictive response was obtained with an electrostrictive coefficient Q33 (˜0.024 m4/C2 at 60 kV/cm) and good thermostability comparable with that of traditional Pb-based electrostrictors. Even at an electric-field as low as 35 kV/cm or at a temperature as high as 180 °C, samples still possess a large electrostrictive response with Q33 > 0.022 m4/C2, suggesting it is very promising for practical applications as a lead-free electrostrictive material owning to its wide usage range. Moreover, reducing the applied electric-filed or increasing temperature can both induce the predominant to pure electrostriction transition due to the little contributions of electrostriction strain from ferroelectric domain switching. Our work may provide a new recipe for designing high-performance BNT-based lead-free electrostrictive materials by means of texture construction.

  2. First-principles studies on Ti 3Si 0.5Ge 0.5C 2 under pressure

    NASA Astrophysics Data System (ADS)

    Feng, Wenxia; Hu, Haiquan; Cui, Shouxin; Zhang, Guiqing; Lv, Zengtao; Wu, Cheng

    2011-11-01

    The structural, electronic and elastic properties of Ti 3Si 0.5Ge 0.5C 2 have been investigated by using the pseudopotential plane-wave method within the density-functional theory. Our calculated equation of state (EOS) is consistent with the experimental results. The density of states (DOS) indicates that Ti 3Si xGe 1- xC 2 ( x=0, 0.5, 1.0) are metallic, and these compounds have nearly the same electrical conductivity. The elastic constants for Ti 3Si 0.5Ge 0.5C 2 are obtained at zero pressure, which is compared to Ti 3SiC 2 and Ti 3GeC 2. We can conclude that Ti 3Si 0.5Ge 0.5C 2 is brittle in nature by analyzing the ratio between bulk and shear moduli. There appears to be little effect on the electronic and elastic properties with the Ge substitution to Si atoms in Ti 3SiC 2.

  3. Enhanced susceptibility in LNiO3 perovskites ( L = La,Pr,Nd,Nd0.5Sm0. 5)

    PubMed

    Zhou; Goodenough; Dabrowski; Klamut; Bukowski

    2000-01-17

    The temperature dependence of the resistivity rho(T) and of the dc magnetic susceptibility chi(T) were measured on high-quality LNiO3 (L = La,Pr,Nd,Nd0.5Sm0.5) samples synthesized under high oxygen pressure. Subtraction of the rare-earth contribution to chi(T) allows the presentation of the evolution of the susceptibility of the NiO3 array from Pauli to Curie-Weiss paramagnetism with decreasing bandwidth. A metal-insulator transition occurring at a temperature T(t) = T(N) is first order for L = Pr and Nd; it becomes second order and produces no anomaly in chi(-1)(T) at a T(t)>T(N) for L = Nd0.5Sm0.5. In the antiferromagnetic domain T

  4. Highly Textured Superconducting FeSe0.5Te0.5 Thin Films on Glass Substrates

    NASA Astrophysics Data System (ADS)

    Chen, Li; Tsai, Chen-Fong; Lee, Joon Hwan; Zhang, Xinghang; Wang, Haiyan

    2013-02-01

    Superconducting FeSe0.5Te0.5 thin films are deposited on amorphous substrates, i.e., glass substrates by a pulsed laser deposition (PLD) technique. Microstructural characterizations show that the films are highly textured along (00l) with good crystallinity. The superconducting critical transition temperature (Tc) ranges from ˜8 to ˜10 K. The self-field critical current density (Jcsf) at 4 K is ˜1.2×104 A/cm2. The in-field critical current density (Jcinfield) decreases slowly under high magnetic field confirmed by both transport and magnetization measurements. The growth of high quality superconducting FeSe0.5Te0.5 thin films on amorphous substrates demonstrates a low cost architecture for future Fe-based superconductor coated conductors.

  5. Superconductivity induced by In substitution into the topological crystalline insulator Pb0.5Sn0.5Te

    NASA Astrophysics Data System (ADS)

    Zhong, R. D.; Schneeloch, J. A.; Liu, T. S.; Camino, F. E.; Tranquada, J. M.; Gu, G. D.

    2014-07-01

    Indium substitution turns the topological crystalline insulator (TCI) Pb0.5Sn0.5Te into a possible topological superconductor. To investigate the effect of the indium concentration on the crystal structure and superconducting properties of (Pb0.5Sn0.5)1-xInxTe, we have grown high-quality single crystals using a modified floating-zone method and have performed systematic studies for indium content in the range 0≤x≤0.35. We find that the single crystals retain the rocksalt structure up to the solubility limit of indium (x ˜0.30). Experimental dependencies of the superconducting transition temperature (Tc) and the upper critical magnetic field (Hc2) on the indium content x have been measured. The maximum Tc is determined to be 4.7 K at x =0.30, with μ0Hc2(T =0)≈5 T.

  6. Strong red emission in Pr doped (Bi0.5Na0.5)TiO3 ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Sun, Haiqin; Peng, Dengfeng; Wang, Xusheng; Tang, Mianmian; Zhang, Qiwei; Yao, Xi

    2011-07-01

    The photoluminescence of Pr doped (Bi0.5Na0.5)TiO3 ferroelectric ceramics prepared by conventional solid-state reaction were investigated. A bright red emission is observed at room temperature, which ascribed to 1D2→3H4 transition. The excitation bands are mainly located at 440 ˜ 505 nm, which is adaptable to the emission band of commercial blue light-emitting diodes (LEDs) chips. The optimal emission intensity was also obtained when Pr doping level was 0.003 mol. Meanwhile, the enhanced ferroelectric properties were obtained by Pr doping. The results show that Pr doped (Bi0.5Na0.5)TiO3 ceramics as a multifunctional material may be useful for white LEDs, sensor, and optical-electro integration.

  7. Photocarrier dynamics in transition metal dichalcogenide alloy Mo0.5W0.5S2.

    PubMed

    He, Jiaqi; He, Dawei; Wang, Yongsheng; Zhao, Hui

    2015-12-28

    We report a transient absorption study of photocarrier dynamics in transition metal dichalcogenide alloy, Mo0.5W0.5S2. Photocarriers were injected by a 400-nm pump pulse and detected by a 660-nm probe pulse. We observed a fast energy relaxation process of about 0.7 ps. The photocarrier lifetime is in the range of 50 - 100 ps, which weakly depends on the injected photocarrier density and is a few times shorter than MoS2 and WS2, reflecting the relatively lower crystalline quality of the alloy. Saturable absorption was also observed in Mo0.5W0.5S2, with a saturation energy fluence of 32 μJ cm(-2). These results provide important parameters on photocarrier properties of transition metal dichalcogenide alloys. PMID:26832001

  8. Structural and Dielectric Studies on Pb(Mg0.5Mo0.5)O3 Compound

    NASA Astrophysics Data System (ADS)

    Barbur, I.; Ardelean, I.; Borodi, G.; Ciomos, D.

    Structural and dielectric measurements were performed on Pb(Mg0.5Mo0.5)O3 (PMM). Polycrystalline samples of PMM were synthesized by solid-state reaction technique at normal pressure. The X-ray measurements indicate formation of single-phase perovskite structure with absence of Mg and Mo ions ordering. The temperature dependence of the relative dielectric constant suggests that PMM undergoes a phase transition (FE or AFE) at 63°C.

  9. Interrelation between Structure Magnetic Properties in La0.5Sr0.5CoO3

    SciTech Connect

    Biegalski, Michael D; Takamura, Y; Mehta, A; Gai, Zheng; Kalinin, Sergei; Ambaye, Hailemariam; Lauter, Valeria; He, Jun; Kim, Young Min; Borisevich, Albina Y; Siemons, Wolter; Christen, Hans M

    2014-01-01

    Differing anisotropic strain induced from the underlying substrates not only control the long-range structural symmetries in La0.5Sr0.5CoO3 but also impact the magnetic properties of these epitaxial thin films. The two dominant structural distortions: oxygen octahedral tilts and epitaxial strain, however, have complex and non-intuitive effects on the splitting of the t2g states and consequently on magnetization.

  10. Solid state synthesis and characterization of bulk FeTe0.5Se0.5 superconductors

    NASA Astrophysics Data System (ADS)

    Onar, K.; Yakinci, M. E.

    2016-01-01

    FeTe0.5Se0.5 polycrystalline superconductor samples were synthesized by solid- state reaction method at different heating temperatures. The morphological and structural characterization of FeTe0 5Se0.5 samples were carried out by X-rays Diffraction, Scanning Electron Microscope and Energy Dispersive X-ray Spectroscopy. The electrical, magnetic and thermal transport properties were investigated up to 8 T by using physical property measurement system. The results reveal that the sensitivity of electrical and magnetic properties strongly depends on the heat treatment cycles. The upper critical field, Hc2(0), was determined with the magnetic field parallel to the sample surface. It gives a maximum value of 36.3 T. The lower critical field, Hc1(T), was obtained as 210, 140 and 70 Oe at 5, 8 and 12 K, respectively. The coherence length, ξ, at the zero field, was calculated to be 1.94 nm and suggested a transparent intergrain boundaries peculiarity. The μ0Hc2(0)/kBTc rate shows higher value (3.36 T/K) than the Pauli limit (1.84 T/K) which suggests unconventional nature of superconductivity for the polycrystalline FeTe0.5Se0.5 superconducting samples.

  11. Fabrication and Characterization of Mn0.5Zn0.5Fe2O4 Magnetic Nanofibers

    NASA Astrophysics Data System (ADS)

    Xiang, Jun; Shen, Xiang-Qian; Song, Fu-Zhan; Meng, Xian-Feng

    2010-01-01

    Mn0.5Zn0.5Fe2O4 Magnetic nanofibers were fabricated by calcining electrospun polymer/inorganic composite nanofibers and characterized by thermogravimetric and differential thermal analysis, x-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy and a vibrating sample magnetometer. The experimental results show that the pure spinel structure is basically formed when the composite nanofibers are calcined at 450°C for 2h. With the increasing calcination temperature, both the saturation magnetization and coercivity of nanofiber samples increase initially along with the growth of Mn0.5Zn0.5Fe2O4 nanocrystals contained in the nanofibers. However, when the calcination temperature reaches 550°C, the saturation magnetization of nanofibers starts to dramatically decrease owing to the formation of the α-Fe2O3 phase at this temperature. The prepared Mn0.5Zn0.5Fe2O4 nanofibers calcined at 500°C for 2h have diameters ranging from 100 to 200nm. Their saturation magnetization and coercivity are 12.37 emu/g and 4.81 kA/m at room temperature, respectively.

  12. In0.5Ga0.5As self-assembled quantum dots on GaP/Si

    NASA Astrophysics Data System (ADS)

    Song, Yuncheng

    This thesis focuses on demonstrating monolithic integration of III-V optoelectronic devices with Si by means of GaP on Si templates. Though high-quality epitaxial GaP on Si has been developed, GaP itself is not useful for most photonic applications due to its indirect bandgap. Historically, deep level impurities have allowed the realization of GaP light emitting diodes (LEDs), but these devices had low efficiency and the gain was insufficient for laser action. The lattice matched dilute nitride material Ga(NAsP) is an option for direct bandgap material on GaP, but N-related point defects make the material challenging to grow. InxGa1--xAs self-assembled quantum dots (SAQDs) grown on GaP offer another path to integration of direct-bandgap III-V material onto Si. The use of InxGa 1--xAs allows access to a wide range of bulk bandgaps (1.42-0.36 eV for x=0-1) and the potential for great flexibility in emission wavelength from visible to near-infrared. While chip-to-chip optical communication remains a goal, a range of sensing applications could also benefit from the direction integration of Si electronics with light sources. Sample growth was carried out by solid-source molecular beam epitaxy (MBE) using conditions similar to those used for the well-known case of InAs/GaAs SAQDs. SAQD formation was through Stranski--Krastanov (S-K) growth mode, as evidenced by reflection high-energy electron diffraction (RHEED) and transmission electron microscopy (TEM). Cross-sectional transmission microscopy (XTEM) with several two-beam conditions confirmed that both the SAQDs and the GaP cap layer were free of dislocations. Intense photoluminescence was visible from the quantum dots at both 80 K and room temperature to the unaided eye in ambient lighting. The photoluminescence results also showed that emission energy can be controlled by varying the In0.5Ga0.5As deposition thickness. The commercial availability of high-quality GaP/Si templates enabled research on In0.5Ga0.5As

  13. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR COMMERCIAL AND PRIVATE OPERATIONS § 5.10 Eating, drinking, or lodging establishments. (a) No establishment offering food,...

  14. 29 CFR 5.10 - Restitution, criminal action.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 1 2013-07-01 2013-07-01 false Restitution, criminal action. 5.10 Section 5.10 Labor... Procedures § 5.10 Restitution, criminal action. (a) In cases other than those forwarded to the Attorney... in violation of a criminal statute, the matter shall be forwarded to the Attorney General of...

  15. 29 CFR 5.10 - Restitution, criminal action.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Restitution, criminal action. 5.10 Section 5.10 Labor Office... Procedures § 5.10 Restitution, criminal action. (a) In cases other than those forwarded to the Attorney... in violation of a criminal statute, the matter shall be forwarded to the Attorney General of...

  16. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 1 General Provisions 1 2012-01-01 2012-01-01 false Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  17. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1 General Provisions 1 2011-01-01 2011-01-01 false Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  18. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1 General Provisions 1 2010-01-01 2010-01-01 false Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  19. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 1 General Provisions 1 2014-01-01 2012-01-01 true Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  20. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 1 General Provisions 1 2013-01-01 2012-01-01 true Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  1. Dielectric relaxation and magnetodielectric response in DyMn0.5Cr0.5O3

    NASA Astrophysics Data System (ADS)

    Yuan, B.; Yang, J.; Zuo, X. Z.; Kan, X. C.; Zu, L.; Zhu, X. B.; Dai, J. M.; Song, W. H.; Sun, Y. P.

    2015-09-01

    We investigate the structural, magnetic, and magnetodielectric properties of DyMn0.5Cr0.5O3. The sample can be indexed with an orthorhombic phase with B site disordered space group Pbnm. The valence state of both Mn and Cr ions are suggested to be +3 based on the results of x-ray photoelectron spectroscopy. Two thermally excited dielectric relaxation at temperatures TN2 < T< 300 K and large magnetodielectric effect (MDC = 20%-30%) due to the disordered arrangement of Mn3+/Cr3+ ions associated with electron hopping between them are observed. The absence of any noticeable magnetoresistance effect (MR < 0.5%) demonstrates that the observed magnetodielectric effect is an intrinsic behavior. These results suggest that DyMn0.5Cr0.5O3 is a magnetodielectric compound, whose dielectric properties are dependence of the applied magnetic field, which exhibits such effects near room temperature and holds great promise for future device applications.

  2. Charge-ordered ferromagnetic phase in La(0.5)Ca(0.5)MnO3.

    PubMed

    Loudon, James C; Mathur, Neil D; Midgley, Paul A

    Mixed-valent manganites are noted for their unusual magnetic, electronic and structural phase transitions. For example, the La(1-x)Ca(x)MnO(3) phase diagram shows that below transition temperatures in the range 100-260 K, compounds with 0.2 < x < 0.5 are ferromagnetic and metallic, whereas those with 0.5 < x < 0.9 are antiferromagnetic and charge ordered. In a narrow region around x = 0.5, these totally dissimilar ground states are thought to coexist. It has been shown that charge order and charge disorder can coexist in the related compound, La(0.25)Pr(0.375)Ca(0.375)MnO(3). Here we present electron microscopy data for La(0.5)Ca(0.5)MnO(3) that shed light on the distribution of these coexisting phases, and uncover an additional, unexpected phase. Using electron holography and Fresnel imaging, we find micrometre-sized ferromagnetic regions spanning several grains coexisting with similar-sized regions with no local magnetization. Holography shows that the ferromagnetic regions have a local magnetization of 3.4 +/- 0.2 Bohr magnetons per Mn atom (the spin-aligned value is 3.5 micro (B) per Mn). We use electron diffraction and dark-field imaging to show that charge order exists in regions with no net magnetization and, surprisingly, can also occur in ferromagnetic regions. PMID:12490944

  3. Charge-ordered ferromagnetic phase in La0.5Ca0.5MnO3

    NASA Astrophysics Data System (ADS)

    Loudon, James C.; Mathur, Neil D.; Midgley, Paul A.

    2002-12-01

    Mixed-valent manganites are noted for their unusual magnetic, electronic and structural phase transitions. For example, the La1-xCaxMnO3 phase diagram shows that below transition temperatures in the range 100-260K, compounds with 0.2 < x < 0.5 are ferromagnetic and metallic, whereas those with 0.5 < x < 0.9 are antiferromagnetic and charge ordered. In a narrow region around x = 0.5, these totally dissimilar ground states are thought to coexist. It has been shown that charge order and charge disorder can coexist in the related compound, La0.25Pr0.375Ca0.375MnO3. Here we present electron microscopy data for La0.5Ca0.5MnO3 that shed light on the distribution of these coexisting phases, and uncover an additional, unexpected phase. Using electron holography and Fresnel imaging, we find micrometre-sized ferromagnetic regions spanning several grains coexisting with similar-sized regions with no local magnetization. Holography shows that the ferromagnetic regions have a local magnetization of 3.4 +/- 0.2Bohr magnetons per Mn atom (the spin-aligned value is 3.5µB per Mn). We use electron diffraction and dark-field imaging to show that charge order exists in regions with no net magnetization and, surprisingly, can also occur in ferromagnetic regions.

  4. Magnetocaloric and phase coexistence in La0.5Ca0.5-xSrxMnO3 manganites

    NASA Astrophysics Data System (ADS)

    Khondabi, M.; Ahmadvand, H.; Kameli, P.; Amirzadeh, P.; Salamati, H.; Dasgupta, P.; Poddar, A.

    2015-12-01

    Structural, magnetic, and magnetocaloric properties of the phase separated La0.5Ca0.5-xSrxMnO3 (x = 0, 0.2, 0.3, 0.4, and 0.5) manganites have been studied. The results show that the phase coexistence state can be investigated by magnetocaloric studies (especially the field dependence of magnetic entropy change at constant temperature). Magnetic entropy change (△SM) shows positive (negative) peak at the vicinity of TN (TC). However, in the intermediate temperatures between TN and TC, both the sign and magnitude of △SM are strongly dependent on temperature and magnetic field, manifesting the competition of ferromagnetic (FM) (negative △SM) and non-FM (positive △SM) phases. This behavior is more pronounced in the parent compound, La0.5Ca0.5MnO3, in which the intermediate phase separation ranges between 160 and 225 K. The substitution of Ca by Sr enhances the ferromagnetic state, weakens the phase separation, and thus narrows the temperature range in which the field related effects (such as the sign change of △SM) are observed.

  5. Structural And Electrical Properties oF (La0.5-xPrxBa0.5)(Mn0.5Ti0.5)O3 Perovskite

    NASA Astrophysics Data System (ADS)

    Alias, Nor Hayati; Shaari, Abdul Halim; Wan Yusoff, Wan Mohd Daud; Mahmood, Che Seman

    2010-01-01

    A single phase monoclinic new perovskite based titano-manganite (La0.5-xPrxBa0.5)(Mn0.5Ti0.5)O3 has been successfully prepared by ceramic solid-state technique at sintering temperature of 1300° C. The concentration of Pr (Praseodymium), x, in molar proportion in A site has been varied as x = 0, 0.02 and 0.2. Analysis has been carried out to determine the electrical properties of the synthesized material at frequency ranging from 5 Hz to 1 MHz; and at temperature range between 25° C to 200° C. It is found that Pr addition promoted liquid phase sintering diffusion, porosity and agglomeration formation at 1300° C. Dual relaxation is observed in unsubstituted Pr sample x = 0 and high Pr substituted sample x = 0.2. This phenomenon was a combinational contribution from a quasi dc (QDC) or low frequency dispersion (LFD), two cole-cole relaxational responses and a resistor. While low concentrated Pr substituted sampled x = 0.02 shows a combinational contribution from a quasi dc (QDC) or low frequency dispersion (LFD), single cole-cole relaxational response and a resistor at room temperature. Pr substitution at x = 0 (max 12000) and x = 0.2 (max 16000) showed high dielectric values compared to low substituted sample x = 0.02. Variation of dielectric loss tangent (tan δ) are observed for all samples at temperature ranged studied.

  6. Synthesis and characterization of (Bi{sub 0.5}Ba{sub 0.5}) (Fe{sub 0.5}Ti{sub 0.5}) O{sub 3} ceramic

    SciTech Connect

    Parida, B.N.; Das, Piyush R.; Padhee, R.; Suara, D.; Mishra, A.; Rout, J.; Choudhary, R.N.P.

    2015-01-15

    Graphical abstract: Temperature variation of (a) dielectric constant (b) dielectric loss of the sample. - Highlights: • The high values of dielectric permittivity and low value of tangent loss. • It used for microwave applications. • The impedance and dielectric relaxation in the material is non exponential and non Debye-type. • Its ac conductivity obeys Jonscher universal power law. - Abstract: The polycrystalline sample of (Bi{sub 0.5}Ba{sub 0.5}) (Fe{sub 0.5}Ti{sub 0.5}) O{sub 3} (BF–BT) was prepared by a standard mixed oxide method. Analysis of room temperature XRD pattern and Raman/FTIR spectra of the compound does not exhibit any change in its crystal structure of BaTiO{sub 3} on addition of BiFeO{sub 3} in equal ratio. The surface morphology of the gold-plated sintered pellet sample recorded by SEM (scanning electron microscope) exhibits a uniform distribution of grains with less porosity. Detailed studies of nature and quantity of variation of dielectric constant, tangent loss, and polarization with temperature and frequency indicate the existence of ferroelectric phase transition at high-temperature. There is a low-temperature anti-ferromagnetic phase transition below 375 °C in the material. Detailed studies of electrical properties (impedance, modulus, etc.) of the material confirmed a strong correlation between micro-structure and properties.

  7. Phase diagram and electrostrictive properties of Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Zhang, Shan-Tao; Yan, Feng; Yang, Bin; Cao, Wenwu

    2010-09-01

    Phase diagram of Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3 ternary system has been analyzed and (0.94-x)BNT-0.06BT-xKNN (0.15≤x≤0.30) ceramics have been prepared and investigated. Pseudocubic structures were confirmed by x-ray diffractions and its preliminary Rietveld refinements. P-E, S-E, and S-P2 profiles (where P, E, and S denote polarization, electric field, and strain, respectively) indicate electrostrictive behavior of all ceramics. The compositions with x =0.20 and 0.25 show pure electrostrictive characteristics. The dissipation energy, electrostrictive strain, and electrostrictive coefficient have been determined and compared with other lead-free and lead-containing electrostrictors. The electrostrictive coefficient can reach as high as 0.026 m4/C2, about 1.5 times of the value of traditional Pb-based electrostrictors.

  8. High-field electromechanical response of Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 across its morphotropic phase boundary

    NASA Astrophysics Data System (ADS)

    Moosavi, A.; Bahrevar, M. A.; Aghaei, A. R.; Ramos, P.; Algueró, M.; Amorín, H.

    2014-02-01

    Lead-free (1 - x)Bi0.5Na0.5TiO3-xBi0.5K0.5TiO3 [(BNKTx); x = 0.18, 0.20, 0.22, 0.24] piezoelectric ceramics were prepared via conventional solid-state reactions. Phase characterization using x-ray diffraction showed coexistence of perovskite rhombohedral and tetragonal polymorphs as anticipated for compositions across the morphotropic phase boundary (MPB). Electrical and electromechanical properties were studied as a function of x. Permittivity and polarization figures were comparable to the best values previously reported. Largest piezoelectric and high field electromechanical responses were obtained for BNKT0.20 samples, considered to have optimum MPB phases. This material exhibited giant field-induced strains of 0.13% and 0.38% under electric fields of 1 and 2.4 kV mm-1 at room temperature by a phase-change mechanism. Figures are comparable to those reported for other BNT-based systems, but under significantly lower driving fields, which is a clear advantage for actuation.

  9. Structure, electrical properties and temperature characteristics of Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3-Bi0.5Li0.5TiO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Lin, Dunmin; Zheng, Qiaoji; Xu, Chenggang; Kwok, K. W.

    2008-11-01

    (1- x- y)Bi0.5Na0.5TiO3- xBi0.5K0.5TiO3- yBi0.5Li0.5TiO3 lead-free piezoelectric ceramics have been prepared by an ordinary sintering technique, and their structure, electrical properties, and temperature characteristics have been studied systematically. The ceramics can be well-sintered at 1050-1150 °C. The increase in K+ concentration decreases the grain-growth rate and promotes the formation of grains with a cubic shape, while the addition of Li+ decreases greatly the sintering temperature and assists in the densification of BNT-based ceramics. The results of XRD diffraction show that K+ and Li+ diffuse into the Bi0.5Na0.5TiO3 lattices to form a solid solution with a pure perovskite structure. As x increases from 0.05 to 0.50, the ceramics transform gradually from rhombohedral phase to tetragonal phase and consequently a morphotropic phase boundary (MPB) is formed at 0.15≤ x≤0.25. The concentration y of Li+ has no obvious influence on the crystal structure of the ceramics. Compared with pure Bi0.5Na0.5TiO3, the partial substitution of K+ and Li+ for Na+ lowers greatly the coercive field E c and increases the remanent polarization P r of the ceramics. Because of the MPB, lower E c and large P r, the piezoelectricity of the ceramics is improved significantly. For the ceramics with the compositions near the MPB ( x=0.15-0.25 and y=0.05-0.10), the piezoelectric properties become optimum: piezoelectric coefficient d 33=147-231 pC/N and planar electromechanical coupling factor k P=20.2-41.0%. In addition, the ceramics exhibit relaxor characteristic, which probably results from the cation disordering in the 12-fold coordination sites. The depolarization temperature T d shows a strong dependence on the concentration x of K+ and reaches the lowest values at the MPB. The temperature dependences of the ferroelectric and dielectric properties at high temperatures may imply that the ceramics may contain both the polar and non-polar regions at temperatures above T d.

  10. Microwave properties of Ba0.5Sr0.5TiO3 thin film coplanar phase shifters

    NASA Astrophysics Data System (ADS)

    Suherman, P. M.; Jackson, T. J.; Tse, Y. Y.; Jones, I. P.; Chakalova, R. I.; Lancaster, M. J.; Porch, A.

    2006-05-01

    Coplanar waveguide transmission lines have been used to show that the temperature dependent properties of Ba0.5Sr0.5TiO3 thin films used for microwave phase shifters in the frequency range 45 MHz-50 GHz are correlated strongly with the microstructure of the films. The highest tunability and figure of merit of the phase shifters were obtained for films with the narrowest ferroelectric-paraelectric phase transition range, lowest mosaic spread, and widest columnar microstructure. The study also showed that the operating temperature plays an important role in achieving the optimum phase shift for microwave applications.

  11. Strain enhanced charge order melting in Pr0.5Ca0.5MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Baisnab, Dipak Kumar; Kumary, T. Geetha; Satya, A. T.; Mani, Awadhesh; Janaki, J.; Nithya, R.; Vaidhyanathan, L. S.; Janawadkar, M. P.; Bharathi, A.

    2011-06-01

    The effect of strain on charge order melting in half doped manganite Pr0.5Ca0.5MnO3 thin films of different thicknesses has been investigated. The films were deposited on (100) oriented MgO substrates by pulsed laser deposition technique and were characterized by x-ray diffraction, electrical resistivity and magnetoresistance measurements. A field induced charge order melting is observed for films with very small thickness. The charge order transition temperature and the magnetic field induced charge order melting appears to be governed by the nature of strain that is experienced by the film.

  12. Radiation hardness of Ga0.5In0.5 P/GaAs tandem solar cells

    NASA Technical Reports Server (NTRS)

    Kurtz, Sarah R.; Olson, J. M.; Bertness, K. A.; Friedman, D. J.; Kibbler, A.; Cavicchi, B. T.; Krut, D. D.

    1991-01-01

    The radiation hardness of a two-junction monolithic Ga sub 0.5 In sub 0.5 P/GaAs cell with tunnel junction interconnect was investigated. Related single junction cells were also studied to identify the origins of the radiation losses. The optimal design of the cell is discussed. The air mass efficiency of an optimized tandem cell after irradiation with 10(exp 15) cm (-2) 1 MeV electrons is estimated to be 20 percent using currently available technology.

  13. Exact size control of KTa0.5Nb0.5O3 nanoparticles using flexible hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Lin, Jiaqi; Chen, Gaoru; Yang, Wenlong; Jiang, Zhichao; Li, Haidong; Wang, Li; Yan, Zhehua; Wang, Xuan; Lei, Qingquan

    2016-04-01

    KTa0.5Nb0.5O3 (KTN) nanoparticles with a perovskite structure were synthesized in orthogonal experiments under different hydrothermal conditions. Controlled sizes were generated by analyzing four variables using an orthogonal array experimental design (OA16 matrix): reaction temperature, KOH concentration, reaction time and solution volume. The effects of the four factors on the KTN nanoparticle size were systematically examined using range analysis and analysis of variance. The KOH concentration had the largest effect on the average size of the KTN nanoparticles. The KTN particles with a designed grain size can be obtained by controlling the four effect factors.

  14. Impedance and modulus spectroscopy analysis of Mn0.5Zn0.5Fe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Aireddy, H.; Bidayat, U.; Das, A. K.

    2013-02-01

    Nanocrystalline spinel ferrite of Mn0.5Zn0.5Fe2O4 was prepared by sol-gel method. Structural analysis using high resolution X-ray diffraction, scanning electron microscope, and high resolution transmission electron microscope, reveals the formation of single phase compound in cubic symmetry of spinel structure. The variation of impedance spectra with temperature indicates retention of typical negative temperature coefficient of resistivity, and the presence of temperature dependent electrical relaxation phenomena. Complex modulus spectra confirmed the presence of non-Debye type single relaxation process. The relaxation observed at low temperatures and low frequencies corresponds to grain boundary polarization.

  15. Infrared absorption spectra of a Nd0.5Ho0.5Fe3(BO3)4 crystal

    NASA Astrophysics Data System (ADS)

    Gerasimova, Yu. V.; Sofronova, S. N.; Gudim, I. A.; Oreshonkov, A. S.; Vtyurin, A. N.; Ivanenko, A. A.

    2016-01-01

    Infrared absorption spectra of a Nd0.5Ho0.5Fe3(BO3)4 crystal in the spectral range of 30-1700 cm-1 have been measured at temperatures from 6 to 300 K. The experimental spectra have been analyzed based on the semiempirical calculation of the lattice dynamics and the analysis of correlation diagrams of borate complexes. No changes associated with structural phase transitions have been detected in the temperature range of measurements; the effect of magnetic ordering on the infrared absorption spectra has not been observed.

  16. Li(V0.5Ti0.5)S2 as a 1 V lithium intercalation electrode

    NASA Astrophysics Data System (ADS)

    Clark, Steve J.; Wang, Da; Armstrong, A. Robert; Bruce, Peter G.

    2016-03-01

    Graphite, the dominant anode in rechargeable lithium batteries, operates at ~0.1 V versus Li+/Li and can result in lithium plating on the graphite surface, raising safety concerns. Titanates, for example, Li4Ti5O12, intercalate lithium at~1.6 V versus Li+/Li, avoiding problematic lithium plating at the expense of reduced cell voltage. There is interest in 1 V anodes, as this voltage is sufficiently high to avoid lithium plating while not significantly reducing cell potential. The sulfides, LiVS2 and LiTiS2, have been investigated as possible 1 V intercalation electrodes but suffer from capacity fading, large 1st cycle irreversible capacity or polarization. Here we report that the 50/50 solid solution, Li1+x(V0.5Ti0.5)S2, delivers a reversible capacity to store charge of 220 mAhg-1 (at 0.9 V), 99% of theoretical, at a rate of C/2, retaining 205 mAhg-1 at C-rate (92% of theoretical). Rate capability is excellent with 200 mAhg-1 at 3C. C-rate is discharge in 1 h. Polarization is low, 100 mV at C/2. To the best of our knowledge, the properties/performances of Li(V0.5Ti0.5)S2 exceed all previous 1 V electrodes.

  17. Superconductivity and abnormal pressure effect in Sr{}_{0.5}La{}_{0.5}FBiSe2 superconductor

    NASA Astrophysics Data System (ADS)

    Li, Lin; Xiang, Yongliang; Chen, Yihong; Jiao, Wenhe; Zhang, Chuhang; Zhang, Li; Dai, Jianhui; Li, Yuke

    2016-04-01

    Through the solid state reaction method, we synthesized a new BiSe2-based superconductor Sr{}0.5La{}0.5FBiSe2 with superconducting transition temperature T {}c ≈ \\quad 3.8 K. A strong diamagnetic signal below T c in susceptibility χ (T) is observed indicating the bulk nature of superconductivity. Different to most BiS2-based compounds where superconductivity develops from a semiconducting-like normal state, the present compound exhibits a metallic behavior down to T c . Under weak magnetic field or pressure, however, a remarkable crossover from metallic to insulating behaviors takes place around T min where the resistivity picks up a local minimum. With increasing pressure, T {}c decreases monotonously and T min shifts to high temperatures, while the absolute value of the normal state resistivity at low temperatures first decreases and then increases with pressure up to 2.5 GPa. These results imply that the electronic structure of Sr{}0.5La{}0.5FBiSe2 may be different to those in the other BiS2-based systems.

  18. Charge ordered ferromagnetic phase in La_0.5Ca_0.5MnO_3

    NASA Astrophysics Data System (ADS)

    Mathur, Neil

    2003-03-01

    Charge order and ferromagnetism should be mutually exclusive in the manganites, because ferromagnetism in these materials is normally promoted by delocalised electrons. Surprisingly, a phase that is both strongly charge ordered and fully ferromagnetic is observed [1] at 90 K in La_0.5Ca_0.5MnO_3, using Fresnel imaging, dark-field TEM and electron holography. This new phase coexists with the two low temperature phases that were already known to coexist in La_0.5Ca_0.5MnO_3. (One of these expected phases is ferromagnetic but not charge-ordered, the other is charge-ordered but not ferromagnetic.) Strain fields could be responsible for the novel microscopic texture presented here - perhaps creating conditions in which nearest neighbour hopping is sufficient to promote ferromagnetism. Similarly, strain fields are believed to cause sub-micron phase separation in the manganites. It therefore seems that the manganites can adapt to their environments over a wide range of length scales [2]. [1] http://xxx.lanl.gov/abs/cond-mat/0209436 [2] Neil Mathur and Peter Littlewood, Physics Today, early 2003.

  19. Octahedral distortion induced magnetic anomalies in LaMn0.5Co0.5O3 single crystals

    NASA Astrophysics Data System (ADS)

    Manna, Kaustuv; Bhadram, Venkata Srinu; Elizabeth, Suja; Narayana, Chandrabhas; Anil Kumar, P. S.

    2014-07-01

    Single crystals of LaMn0.5Co0.5O3 belonging to the ferromagnetic-insulator and distorted perovskite class were grown using a four-mirror optical float zone furnace. The as-grown crystal crystallizes into an orthorhombic Pbnm structure. The spatially resolved 2D Raman scan reveals a strain-induced distribution of transition metal (TM)-oxygen (O) octahedral deformation in the as-grown crystal. A rigorous annealing process releases the strain, thereby generating homogeneous octahedral distortion. The octahedra tilt by reducing the bond angle TM-O-TM, resulting in a decline of the exchange energy in the annealed crystal. The critical behavior is investigated from the bulk magnetization. It is found that the ground state magnetic behavior assigned to the strain-free LaMn0.5Co0.5O3 crystal is of the 3D Heisenberg kind. Strain induces mean field-like interaction in some sites, and consequently, the critical exponents deviate from the 3D Heisenberg class in the as-grown crystal. The temperature-dependent Raman scattering study reveals strong spin-phonon coupling and the existence of two magnetic ground states in the same crystal.

  20. 0.5 gigapixel microscopy using a flatbed scanner.

    PubMed

    Zheng, Guoan; Ou, Xiaoze; Yang, Changhuei

    2013-12-01

    The capability to perform high-resolution, wide field-of-view (FOV) microscopy imaging is highly sought after in biomedical applications. In this paper, we report a wide FOV microscopy system that uses a closed-circuit-television (CCTV) lens for image relay and a flatbed scanner for data acquisition. We show that such an imaging system is capable of capturing a 10 mm × 7.5 mm FOV image with 0.78 µm resolution, resulting in more than 0.5 billion pixels across the entire image. The resolution and field curve of the proposed system were characterized by imaging a USAF resolution target and a hole-array target. To demonstrate its application, 0.5 gigapixel images of histology slides were acquired using this system. PMID:24466471

  1. 0.5% levobupivacaine versus 0.5% ropivacaine: Are they different in ultrasound-guided sciatic block?

    PubMed Central

    Pham Dang, Charles; Langlois, Cécile; Lambert, Chantal; Nguyen, Jean-Michel; Asehnoune, Karim; Lejus, Corinne

    2015-01-01

    Context and Aims: Little is known about onset and duration of sciatic block after 0.5% levobupivacaine (Levo) versus 0.5% ropivacaine (Ropi) for ultrasound-guided technique. We assessed these parameters in the ultrasound-guided block, to know for the practice. Setting and Design: A comparative randomized double-blind study was conducted in the University Hospital. Materials and Methods: Were included 35 adults of ASA I-II, scheduled for foot surgery, presenting clear imaging of their sciatic nerve at mid-thigh. A volume of 20 mL of either 0.5% Levo or 0.5% Ropi were injected around the sciatic nerve at mid-thigh using ultrasound guidance (out of the plane) followed by placement of a catheter to use, if necessary, for perioperative analgesia. A femoral single shot block was systematically performed to block the saphenous nerve. The onset times until complete foot block (primary outcome) and the sensory and motor block duration (secondary outcome) were assessed using Wilcoxon test. Values were expressed as medians (1st-3rd quartile). Results: Except for two delayed sciatic blocks in each group, the onset time otherwise was 35 min (20-60) in Ropi versus 40 min (30-60) in Levo, P = 0.5. Sensory block lasted longer in Levo, 17 h (14-27) compared with 15 h (10-17) in Ropi, P = 0.04. No significant between-group difference was found with motor block durations, 15 h (12-18) in Levo and 15 h (12-16) in Ropi, P = 0.3. Conclusion: No difference of onset times was found in ultrasound-guided sciatic block whether using Levo or Ropi. Levo induced a longer-lasting sensory block. PMID:25558190

  2. Comparative Dielectric and Ferroelectric Characteristics of Bi0.5Na0.5TiO3, CaCu3Ti4O12, and 0.5Bi0.5Na0.5TiO3-0.5CaCu3Ti4O12 Electroceramics

    NASA Astrophysics Data System (ADS)

    Singh, Laxman; Yadava, Shiva Sundar; Sin, Byung Cheol; Rai, Uma Shanker; Mandal, K. D.; Lee, Youngil

    2016-06-01

    The dielectric and ferroelectric characteristics of Bi0.5Na0.5TiO3 (BNT), CaCu3Ti4O12 (CCTO), and 0.5Bi0.5Na0.5TiO3-0.5CaCu3Ti4O12 (BNT/CCTO) ceramics are compared. X-ray diffraction patterns confirmed the formation of single phase of all the ceramics after sintering at 950°C for 15 h. Scanning electron microscopy images of the sintered ceramics reveal average grain sizes in the range from 200 nm to 2.5 μm. Energy-dispersive x-ray mapping and x-ray photoelectron spectroscopy show the presence of the elements Bi, Na, Ca, Cu, Ti, and O with uniform distribution in the ceramics. BNT/CCTO exhibits high dielectric constant ( ɛ r ˜ 6.9 × 104) compared with BNT ( ɛ r ˜ 0.13 × 104) and CCTO ( ɛ r ˜ 1.68 × 104) ceramics at 1 kHz and 503 K. The high dielectric constant of BNT/CCTO compared with BNT and CCTO is associated with a major contribution from grain boundaries, as confirmed by impedance and modulus analyses. The P- E hysteresis loop of all the ceramics measured at room temperature and 50°C exhibited typical ferroelectric nature. The remanent polarization ( P r) of BNT (1.58 μC/cm2) and CCTO (0.654 μC/cm2) ceramics are higher than that of BNT/CCTO (0.267 μC/cm2) ceramic.

  3. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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  4. 46 CFR 30.10-15 - Combustible liquid-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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  5. 46 CFR 30.10-15 - Combustible liquid-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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  6. 46 CFR 30.10-15 - Combustible liquid-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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  7. 46 CFR 30.10-15 - Combustible liquid-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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  8. 46 CFR 30.10-15 - Combustible liquid-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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  9. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Emergency lighting and power systems-T/ALL. 35.10-15... Emergency Requirements § 35.10-15 Emergency lighting and power systems—T/ALL. (a) Where fitted, it shall be the duty of the master to see that the emergency lighting and power systems are tested and...

  10. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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  11. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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  12. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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  13. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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  14. 38 CFR 10.15 - Designation of more than one beneficiary under an adjusted service certificate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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  15. Monoclinic crystal structure of polycrystalline Na0.5Bi0.5TiO3

    NASA Astrophysics Data System (ADS)

    Aksel, Elena; Forrester, Jennifer S.; Jones, Jacob L.; Thomas, Pam A.; Page, Katharine; Suchomel, Matthew R.

    2011-04-01

    Bismuth-based ferroelectric ceramics are currently under intense investigation for their potential as Pb-free alternatives to lead zirconate titanate-based piezoelectrics. Na0.5Bi0.5TiO3 (NBT), one of the widely studied compositions, has been assumed thus far to exhibit the rhombohedral space group R3c at room temperature. High-resolution powder x-ray diffraction patterns, however, reveal peak splitting in the room temperature phase that evidence the true structure as monoclinic with space group Cc. This peak splitting and Cc space group is only revealed in sintered powders; calcined powders are equally fit to an R3c model because microstructural contributions to peak broadening obscure the peak splitting.

  16. Ferroelectricity and ferroelectric resistive switching in sputtered Hf0.5Zr0.5O2 thin films

    NASA Astrophysics Data System (ADS)

    Fan, Zhen; Xiao, Juanxiu; Wang, Jingxian; Zhang, Lei; Deng, Jinyu; Liu, Ziyan; Dong, Zhili; Wang, John; Chen, Jingsheng

    2016-06-01

    Ferroelectric properties and ferroelectric resistive switching (FE-RS) of sputtered Hf0.5Zr0.5O2 (HZO) thin films were investigated. The HZO films with the orthorhombic phase were obtained without capping or post-deposition annealing. Ferroelectricity was demonstrated by polarization-voltage (P-V) hysteresis loops measured in a positive-up negative-down manner and piezoresponse force microscopy. However, defects such as oxygen vacancies caused the films to become leaky. The observed ferroelectricity and semiconducting characteristics led to the FE-RS effect. The FE-RS effect may be explained by a polarization modulated trap-assisted tunneling model. Our study not only provides a facile route to develop ferroelectric HfO2-based thin films but also explores their potential applications in FE-RS memories.

  17. Phase separation and direct magnetocaloric effect in La0.5Ca0.5MnO3 manganite

    NASA Astrophysics Data System (ADS)

    Amirzadeh, P.; Ahmadvand, H.; Kameli, P.; Aslibeiki, B.; Salamati, H.; Gamzatov, A. G.; Aliev, A. M.; Kamilov, I. K.

    2013-03-01

    A series of phase separated La0.5Ca0.5MnO3 manganite samples with different grain sizes were studied by ac susceptibility, direct magnetocaloric effect (ΔT), and heat capacity measurements. The ac susceptibility shows that fractions of ferromagnetic and antiferromagnetic phases and consequently the phase separated state can be controlled by means of sintering temperature. Lower sintering temperature leads to a ferromagnetic state, while higher sintering temperature increases antiferromagnetic phase fraction, resulting in a phase separated state. In the phase separated samples, ΔT shows a conventional positive peak near TC and an anomalous positive peak at lower temperature near TN. The anomalous positive peak appears at higher magnetic field and is accompanied with thermal hysteresis. It is suggested that the anomalous magnetocaloric behaviors result from phase separation and first order magnetostructural phase transition. This study shows that direct magnetocaloric effect is a useful technique for the study of manganites.

  18. Diode pumped Nd:Lu0.5Y0.5VO4-LBO red laser at 671 nm

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Liu, J. Y.; Zhang, Y. C.

    2012-03-01

    We report a efficient compact red laser at 671 nm generation by intracavity frequency doubling of a continuous wave laser operation of a diode pumped Nd:Lu0.5Y0.5VO4 laser on the 4 F 3/2-4 I 13/2 transition at 1342 nm. An LBO crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an absorbed pump power of 17.8 W, as high as 2.25 W of continuous wave output power at 671 nm is achieved with 10-mm-long LBO. The optical-to-optical conversion efficiency is up to 12.6%, and the fluctuation of the red output power was better than 3.6% in the given 30 min.

  19. Complex domain structure in polycrystalline Pb(Sc0.5Nb0.5)O3

    NASA Astrophysics Data System (ADS)

    Ursic, Hana; Drnovsek, Silvo; Malic, Barbara

    2016-03-01

    This letter provides evidence of ferroelectric domains existing in polycrystalline B-site cation disordered Pb(Sc0.5Nb0.5)O3. A complex domain structure with variations in characteristic length and morphology is observed below the relaxor-ferroelectric phase transition at ~98 °C. At room temperature the micrometer-sized wedge-like, lamellar-like and irregularly shaped domains are found. By approaching the relaxor-ferroelectric phase transition temperature, the domain structure changes; the fraction of micrometer-sized domains is progressively decreasing. Approximately 100 nm large domains, which form mottled patterns, are observed, and associated with polar nano domains as described in other relaxor materials.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  1. Synthesis of functionalized Co0.5Zn0.5Fe2O4 nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Bohara, R. A.; Yadav, H. M.; Thorat, N. D.; Mali, S. S.; Hong, C. K.; Nanaware, S. G.; Pawar, S. H.

    2015-03-01

    In this paper, we report a simple one step method for the synthesis of uniform, water dispersible amine functionalized Co0.5Zn0.5Fe2O4 nanoparticles (AF-CZF) of size about 6 nm. The synthesis process was accomplished by refluxing Fe(acac)3, Co(acac)2 and Zn(acac)2 in diethylene glycol and ethanolamine. The magnetic nanoparticles were characterized by XRD, TGDTA, FTIR, SEM and TEM techniques. Their magnetic properties were also studied by using SQUID. The synthesized particles show superparamagnetism at room temperature. AF-CZF nanoparticles exhibit good cell viability, which is above 95% at a concentration of 80 μg mL-1 on MCF7 cell line. The AF-CZF can be a new versatile platform for many interesting biomedical applications.

  2. Zr and Sn substituted (Na0.5Bi0.5)TiO3 -based solid solutions

    NASA Astrophysics Data System (ADS)

    Ishchuk, V. M.; Gusakova, L. G.; Kisel, N. G.; Kuzenko, D. V.; Spiridonov, N. A.; Sobolev, V. L.

    2016-02-01

    The paper attempts to investigate the phase formation of a Zr- and Sn-substituted [(Na0.5Bi0.5)0.80Ba0.20](Ti1-yBy)O3 system during its solid state synthesis. The synthesis was found to be a multi-step process associated with the formation of a number of intermediate phases which however depended on the compositions and sintering temperatures. Single phase solid solutions were obtained when the sintering temperature was increased to 1000 °C-1100 °C. Increase in the concentration of substituting ions, on the one hand, tends to linearly increase the crystal cell size whereas the tolerance factor, on the other hand, gets reduced bolstering the stability of anti-ferroelectric phase as compared to that of ferroelectric phase’.

  3. An In0.5Ga0.5N nanowire photoanode for harvesting deep visible light photons

    NASA Astrophysics Data System (ADS)

    Fan, S.; Woo, S. Y.; Vanka, S.; Botton, G. A.; Mi, Z.

    2016-07-01

    III-nitride semiconductors hold tremendous promise for realizing high efficiency photoelectrodes. However, previously reported InGaN photoelectrodes generally exhibit very low photocurrent densities, due to the presence of extensive defects, dislocations, and indium phase separation. Here, we show that In0.5Ga0.5N nanowires with nearly homogeneous indium distribution can be achieved by plasma-assisted molecular beam epitaxy. Under AM1.5G one sun illumination, the InGaN nanowire photoanode exhibits a photocurrent density of 7.3 mA/cm2 at 1.2 V (vs. NHE) in 1M HBr. The incident-photon-to-current efficiency is above 10% at 650 nm, which is significantly higher than previously reported values of metal oxide photoelectrodes.

  4. Exchange bias in a mixed metal oxide based magnetocaloric compound YFe0.5Cr0.5O3

    NASA Astrophysics Data System (ADS)

    Sharma, Mohit K.; Singh, Karan; Mukherjee, K.

    2016-09-01

    We report a detailed investigation of magnetization, magnetocaloric effect and exchange bias studies on a mixed metal oxide YFe0.5Cr0.5O3 belonging to perovskite family. Our results reveal that the compound is in canted magnetic state (CMS) where ferromagnetic correlations are present in an antiferromagnetic state. Magnetic entropy change of this compound follows a power law (∆SM∼Hm) dependence of magnetic field. In this compound, inverse magnetocaloric effect (IMCE) is observed below 260 K while conventional magnetocaloric effect (CMCE) above it. The exponent 'm' is found to be independent of temperature and field only in the IMCE region. Investigation of temperature and magnetic field dependence studies of exchange bias, reveal a competition between effective Zeeman energy of the ferromagnetic regions and anisotropic exchange energy at the interface between ferromagnetic and antiferromagnetic regions. Variation of exchange bias due to temperature and field cycling is also investigated.

  5. Magnetocaloric and magnetic properties of SmFe0.5Mn0.5O3 complex perovskite

    NASA Astrophysics Data System (ADS)

    Silva-Santana, M. C.; daSilva, C. A.; Barrozo, P.; Plaza, E. J. R.; de los Santos Valladares, L.; Moreno, N. O.

    2016-03-01

    In this paper, we have investigated the physical properties of SmFe0.5Mn0.5O3 complex perovskite samples, synthesized by means of combustion reaction method. X-ray powder diffraction indicates the formation of single phase perovskite with orthorhombic structure. Low magnetic field measurements show remarkable transition at 234 K related to spin reorientation. The magnetocaloric effect shows two peaks related to magnetic behavior changes, at 18 K and at 234 K. The transition about 234 K presents inverse magnetocaloric effect. The entropy variation from magnetocaloric effect shows power law as function of applied magnetic field with maximum entropy change 5.6 J/kg K with field variation of 70 kOe. Critical exponents extracted from ΔS vs. H presents a remarkable sharp peak near antiferromagnetic to weak ferromagnetic transition temperature.

  6. Synthesis and crystal structure of Bi6(Bi0.5Cu0.5)V2O15+y

    NASA Astrophysics Data System (ADS)

    Gupta, Akanksha; Uma, S.

    2015-10-01

    The structure of the oxide with composition Bi6(Bi0.5Cu0.5)V2O15+y has been solved based on single crystal X-ray diffraction and is found to be monoclinic (S. G. I2), a=11.276(1) Å, b=5.4513(2) Å, c=11.055(3) Å, β=96.70°(1). The crystal was twinned by 180° rotoinversion about [ 1 bar 0 1] in the direct lattice as found in the the phosphates, Bi6TiP2O16 and Bi6+xM1-xP2O15+y (M=Mn, Fe and Ni), wherein chains of edge sharing (OBi4) tetrahedral units are connected by layers of VO4 tetrahedra and (Bi/Cu)O6-x (x=oxygen vacancies) octahedra.

  7. Ternary monodispersed Mn0.5Zn0.5Fe2O4 ferrite nanoparticles: preparation and magnetic characterization

    NASA Astrophysics Data System (ADS)

    Parekh, Kinnari; Upadhyay, Ramesh V.; Belova, Lyubov; Rao, K. V.

    2006-12-01

    A ternary system of Mn0.5Zn0.5Fe2O4 has been synthesized for the first time using thermal decomposition of metal acetylacetonate in the presence of a high temperature boiling point solvent and fatty acids. Unlike the results of synthesis of this material by other techniques, we obtain nearly monodispersed nanoparticles, rendering them ideal for applications like in hyperthermia. The crystal structure and morphology of the particles obtained using x-ray diffraction (XRD) and transmission electron microscopy (TEM) are those of a single phase spinel structure with no other impurity phases. The particles are of 7 nm average diameter, with a very narrow (<10%) size distribution. The oleic acid surfactant on the particles shows a 28% weight loss in thermo-gravimetric analyses (TGAs), which corresponds to a monolayer thickness of the coating. Magnetic measurements show the particles to be superparamagnetic with a characteristic blocking temperature of around 50 K.

  8. High pressure Raman study of layered Mo0.5W0.5S2 ternary compound

    NASA Astrophysics Data System (ADS)

    Kim, Joon-Seok; Moran, Samuel T.; Nayak, Avinash P.; Pedahzur, Shahar; Ruiz, Itzel; Ponce, Gabriela; Rodriguez, Daniela; Henny, Joanna; Liu, Jin; Lin, Jung-Fu; Akinwande, Deji

    2016-06-01

    Ternary two-dimensional (2D) transition metal dichalcogenide compounds exhibit a tunable electronic structure allowing for control of the interlayer and the intralayer atomic displacement to efficiently tune their physical and electronic properties. Using a diamond anvil cell, hydrostatic pressure was applied to Mo0.5W0.5S2 up to 40 GPa in order to study the optical phonon vibrational modes. Analysis of the high-pressure Raman spectra shows that the two in-plane E2g modes resembling that of pristine MoS2 and WS2, as well as disorder-activated longitudinal acoustic phonon mode, are hardened and suppressed as pressure increases. The two A1g modes of the ternary compound that resemble the A1g modes of pristine MoS2 and WS2, displayed similar Raman shifts to the pristine compounds as pressure increases. A Raman peak at 470 cm-1 that is close to A1g peaks emerges at ˜8 GPa, which represents a disorder-activated pressure-induced out-of-plane Raman mode observed only in the ternary compound under high pressure. At pressures above ˜30 GPa, a Raman peak at approximately 340 cm-1 is observed, signifying additional disorder-activated vibration mode. Our results reveal the enhanced interactions in the structural and vibrational behavior of the MoS2 and WS2 domains in the Mo0.5W0.5S2 compound under hydrostatic pressure. These results could have implications in understanding the electronic, optical, and structural properties of the new 2D ternary compound materials under extreme mechanical conditions.

  9. Improvement of cycling performance in Ti substituted 0.5Li2MnO3-0.5LiNi0.5Mn0.5O2 through suppressing metal dissolution

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shinji; Noguchi, Hideyuki; Zhao, Wenwen

    2015-03-01

    Ti substituted 0.5Li2MnO3-0.5LiNi0.5Mn0.5O2 cathode material with the composition of Li1.5Ni0.25Mn0.75-xTixO2.5 has been synthesized by spray pyrolysis method. A great variety of characterization methods have been applied to study the influence of Ti substitution for Mn on the structural, morphological and electrochemical performances of Li1.5Ni0.25Mn0.75-xTixO2.5. X-ray diffraction (XRD) results of Li1.5Ni0.25Mn0.75-xTixO2.5 show that they exhibit similar XRD patterns as those of lithium-excess manganese metal oxide based cathode materials. It is confirmed from energy dispersive x-ray spectroscopy (EDX) data that Ti was homogenously substituted for Mn and well distributed in the host structure. X-ray absorption near edge structure (XANES) spectra analysis reveals that oxidation state of Mn in Li1.5Ni0.25Mn0.75-xTixO2.5 remains +4 while that of Ni changes from +2 to +4 during the initial activation process. Further investigation of the local structure of transition metal (TM) ions indicates that Ti has same coordination environment as that of Mn. Drastic capacity fade occurred in full cells with Li1.5Ni0.25Mn0.75O2.5 cathode and graphite anode, while full cell with Ti substituted cathode shows high capacity retention after 100 cycles. Further examination of the amount of dissolved transition metal (TM) ions after long cycling test enable us to demonstrate that substitution of Mn with Ti in Li1.5Ni0.25Mn0.75O2.5 has a significant impact on suppressing the TM ions dissolution and its deposition on both separator and anode thus leads to improved cycleability.

  10. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Public reading room. 5.10 Section 5.10 Education Office of the Secretary, Department of Education AVAILABILITY OF INFORMATION TO THE PUBLIC Agency Records... at the National Library of Education, 400 Maryland Avenue, SW., Plaza Level (Level B), Washington,...

  11. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false Public reading room. 5.10 Section 5.10 Education Office of the Secretary, Department of Education AVAILABILITY OF INFORMATION TO THE PUBLIC Agency Records... at the National Library of Education, 400 Maryland Avenue, SW., Plaza Level (Level B), Washington,...

  12. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Public reading room. 5.10 Section 5.10 Education Office of the Secretary, Department of Education AVAILABILITY OF INFORMATION TO THE PUBLIC Agency Records... at the National Library of Education, 400 Maryland Avenue, SW., Plaza Level (Level B), Washington,...

  13. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Rocky Mountain, Sequoia-Kings Canyon, Yellowstone, and Yosemite National Parks may be operated without a... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF...

  14. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Rocky Mountain, Sequoia-Kings Canyon, Yellowstone, and Yosemite National Parks may be operated without a... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF...

  15. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Rocky Mountain, Sequoia-Kings Canyon, Yellowstone, and Yosemite National Parks may be operated without a... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF...

  16. Switching of morphotropic phase boundary and large strain response in lead-free ternary (Bi0.5Na0.5)TiO3-(K0.5Bi0.5)TiO3-(K0.5Na0.5)NbO3 system

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Shen, Bo; Zhai, Jiwei; Liu, Chunze; Li, Xiaolong; Gao, Xingyu

    2013-03-01

    In this work, we report the phase diagram of lead-free ternary (1 - y)[(1 - x)(Bi0.5Na0.5)TiO3-x(Bi0.5K0.5)TiO3]-y(K0.5Na0.5)NbO3 (BNT-BKT-KNN) system and study the switching characteristics of the morphotropic phase boundary (MPB). The addition of KNN intrinsically changes the structural nature of the system with the shift of MPB from MPB(I) between ferroelectric rhombohedral and ferroelectric tetragonal phases to MPB(II) between ferroelectric rhombohedral and relaxor pseudocubic phases. As the MPB(I) switches to MPB(II), large piezoelectric response with d33 ˜ 150pC/N that obtained for BNT-0.20BKT near MPB(I) almost disappears. Instead, a significant jump of electric-filed-induced strain S up to 0.32%-0.46% (Smax/Emax = 400-575 pm/V) is achieved near MPB(II) due to the shift of the ferroelectric-relaxor transition temperature TF-R down to room temperature. In this study, giant strain ˜0.46% occurs in a very narrow region in the BNT-BKT-KNN system with x = 0.20, y = 0.01, which lies on an underlying tricritical triple point of a rhombohedral (R), tetragonal (T), and pseudocubic (Pc) phases. In-situ high-energy X-ray scattering experiments with external electric field reveal an initial electric-field-induced distortion from the Pc structure for the MPB(II) compositions, while those with single R phase shows no such distortion, which suggests that the large strain achieved near the MPB(II) is likely to be induced by the electric-field-induced structure distortion due to its relative instability structure. We believe that the discovery of a compositional line in the pseudo-ternary system, where the strain response is consistently derivable, should be useful for designing high-performance piezoelectric materials in other BNT-based systems by searching MPBs.

  17. Luminous Red Galaxies at Z=0.4-0.5

    NASA Technical Reports Server (NTRS)

    Heap, Sally; Lindler, Don

    2009-01-01

    We report on a study of approx.20,000 luminous red galaxies (LRG's) at z=0.4-0.5 observed by the Sloan Digital Sky Survey. In order to differentiate among them, we measured restframe magnitudes, u (3000-3500 A), b (4200-4800 A), and y (5700-6300 A) from the spectra themselves. The galaxies show a significant range in restframe colors and absolute magnitudes. We binned the spectra according to the restframe u-b color and y-band absolute magnitude in order to increase the S/N. We used 3 approaches to estimate the ages and metal content of these binned spectra: via their spectral energy distributions, from spectral-line indices, and by full spectral fitting. The three methods usually produce discordant results

  18. Possible radio emission from Uranus at 0.5 MHz

    NASA Technical Reports Server (NTRS)

    Brown, L. W.

    1975-01-01

    Radio emission from the direction of Uranus was detected in data from the radio astronomy experiment on the IMP-6 spacecraft. Previously, emission from the direction of Jupiter and Saturn was observed by the IMP-6 at a number of frequencies near 1 MHz during the period April 1971 to October 1972. These radio bursts were identified in the IMP-6 data through an analysis of the phase of the observed modulated signal detected from the spinning dipole antenna. This technique was applied to the direction of the planet Uranus with possible positive results. Over the approximately 500 days of data, three to six bursts with unique spectral characteristics were found. Identification with Uranus is confused by the likely presence of low level terrestrial and solar emission. The observed events persisted less than three minutes and are strongest in intensity near 0.5 MHz.

  19. BaZr0.5Ti0.5O3 : Lead-free relaxor ferroelectric or dipolar glass

    NASA Astrophysics Data System (ADS)

    Filipič, C.; Kutnjak, Z.; Pirc, R.; Canu, G.; Petzelt, J.

    2016-06-01

    Glassy freezing dynamics was investigated in BaZr0.5Ti0.5O3 (BZT50) ceramic samples by means of dielectric spectroscopy in the frequency range 0.001 Hz-1 MHz at temperatures 10

  20. Colossal elastoresistance, electroresistance and magnetoresistance in Pr0.5Sr0.5MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Chen, Liping; Guo, Xuexiang; Gao, J.

    2016-05-01

    Pr0.5Sr0.5MnO3 thin films on substrates of (001)-oriented LaAlO3 were epitaxially grown by pulsed laser deposition. It was found that a substrate-induced strain of ~1.3% brings a great resistivity change of ~98% at 25 K. We studied the dependence of resistivity on the applied electric current and magnetic field. In the greatly strained films of 60 nm thickness the electroresistance ER=[ρ(I1 μA)-ρ(I1000 μA)]/ρ(I1 μA) reaches ~70% at T=25 K, much higher than ER~7% in the strain-relaxed films of 400 nm thickness, implying the strain effect on ER. Also the magnetoresistance of the film falls with strain-relaxation. Therefore the electric properties of the film could be efficiently modified by strain, electric current and magnetic field. All of them may be explained by the effect on the percolative phase separation and competition in the half-doped manganite material. The manganite films located at phase boundary are expected to be an ideal compound for providing practical colossal effects of elastoresistance, electroresistance and magnetoresistance due to the multiphase coexistence.

  1. Dielectric dynamics of the polycrystalline Ba0.5Sr0.5TiO3 thin films

    NASA Astrophysics Data System (ADS)

    Pečnik, Tanja; Eršte, Andreja; Matavž, Aleksander; Bobnar, Vid; Ivanov, Maksim; Banys, Juras; Xiang, Feng; Wang, Hong; Malič, Barbara; Glinšek, Sebastjan

    2016-05-01

    Polycrystalline Ba0.5Sr0.5TiO3 films, with thicknesses between 90 and 600 nm, were prepared on alumina substrates at 900 °C by chemical solution deposition (CSD) and a dielectric spectroscopy investigation of the in-plane properties was performed. The 5-kHz permittivity ε‧ shows a non-monotonic thickness dependence, reaching 1230 at room temperature for the 310-nm-thick film, whose grain size is ∼75 nm. Its 15-GHz-value and losses are 1105 and 0.05, respectively. The temperature of the permittivity maximum T max at 5 kHz decreases with increasing thickness from 277 to 250 K for the 170- and 600-nm-thick films, respectively, which has been linked to the residual biaxial stress. A hysteresis is observed in the permittivity ε‧-electric field E DC characteristics in all the films up to ∼50 K above T max . Frequency dispersion in which permittivity decreases with increasing frequency is present below T max in films thicker than 90 nm. The high permittivity values of the thinnest films, which are among the highest reported in the (Ba,Sr)TiO3 films with grain sizes below 75 nm, are a direct proof of the optimized CSD processing conditions.

  2. Structural characteristics of thermally evaporated Cu0.5Ag0.5InSe2 thin films

    NASA Astrophysics Data System (ADS)

    Gullu, H. H.; Parlak, M.

    2016-05-01

    In this work, Cu0.5Ag0.5InSe2 (CAIS) thin film samples were prepared by thermal evaporation of Cu, Ag, InSe and Se evaporants sequentially on glass substrates. Following the deposition, annealing processes were applied at different temperatures. The as-grown and annealed CAIS samples were nearly stoichiometric in the detection limit of the compositional measurement. The x-ray diffraction (XRD) measurements revealed that they were in polycrystalline structure with a preferred orientation along the (112) direction. Moreoever, the crystallinity of the films improved with increasing annealing temperature. According to the results of Raman measurements, the highest Raman intensity was found in the A1 mode which is directly proportional to the crystallinity of the samples. The surface properties of the thin films were analyzed by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM). These results showed that there was a Se agglomeration on the deposited film surfaces and with annealing processes segregation effects were observed on the surface of the annealed samples. X-ray photoelectron spectroscopy (XPS) measurements were carried out to get information about surface and near-surface properties of the films. The results from the surface and depth surface analyses of the films were found to be in agreement with the energy dispersive spectroscopy (EDS) analysis.

  3. Structural and dielectric properties of lead free Bi0.5Na0.5TiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Pattipaka, Srinivas; Mahesh, P.; Pamu, D.

    2016-05-01

    The lead free Bi0.5Na0.5TiO3 (BNT) ceramics were synthesized by using a solid state reaction method. The effect of sintering temperature on structure and dielectric properties of BNT ceramics studied systematically. It was observed that the samples calcined at 800 °C and sintered at 1100 °C shown the maximum density (5.67 g/cm3), with larger crystallite size (52 nm), high dielectric constant (ɛr = 694 at 1 kHz), and low dielectric loss (tanδ = 0.103). The XRD pattern reveals that rhombohedral phase with R3c space group at room temperature. The temperature dependent ɛr and tanδ displayed the two phase transitions including ferroelectric to anti-ferroelectric low phase transition (198 °C) and anti-ferroelectric to para electric phase transition (330 °C). The high frequency dielectric analysis revealed that weak relaxor behaviour presented in the system.

  4. Hydrothermal synthesis, evolution, and electrochemical performance of LiMn0.5Fe0.5PO4 nanostructures.

    PubMed

    Xiang, Wei; Zhong, Yan-Jun; Ji, Jun-Yi; Tang, Yan; Shen, HuiHui; Guo, Xiao-Dong; Zhong, Ben-He; Dou, Shi Xue; Zhang, Zhi-Ye

    2015-07-28

    LiMn0.5Fe0.5PO4 (LMFP) materials are synthesized by the hydrothermal approach in an organic-free and surfactant-free aqueous solution. The phase and morphological evolution of the material intermediates at different reaction temperatures and times are characterized by XRD, SEM and TEM, respectively. The results show that during temperature increase, the solubility product (Ksp) of the precursors (Li3PO4, Fe3(PO4)2 and (Mn,Fe)3(PO4)2) is the decisive parameter for the precipitation processes. Once the temperature locates at the range of 100-110 °C, the unstable precursors dissolve quickly and then LMFP nuclei are formed, followed by a dissolution-reprecipitation process. As the reaction progresses, the primary particles self-aggregate to form rod or plate particles to reduce the overall surface energy through oriented attachment (OA) and the Ostwald ripening (OR) mechanism. Moreover, the resultant concentration of the precursor significantly affects the crystal size of LMFP by altering the supersaturation degree of solution at the nucleation stage. The carbon coated LMFP nanostructure synthesized at 0.6 mol L(-1) (resultant concentration of PO4(3-)) delivers discharge capacities of 155, 100 and 81 mA h g(-1) at 0.1, 5 and 20 C rate, respectively. The understanding of nanostructural evolution and its influence on the electrochemical performance will pave a way for a high-performance LMFP cathode. PMID:26119980

  5. Compositional inhomogeneityand segregation in (K0.5Na0.5)NbO3 ceramics

    DOE PAGESBeta

    Chen, Kepi; Tang, Jing; Chen, Yan

    2016-03-11

    The effects of the calcination temperature of (K0.5Na0.5)NbO3 (KNN) powder on the sintering and piezoelectric properties of KNN ceramics have been investigated in this report. KNN powders are synthesized via the solid-state approach. Scanning electron microscopy and X-ray diffraction characterizations indicate that the incomplete reaction at 700 °C and 750 °C calcination results in the compositional inhomogeneity of the K-rich and Na-rich phases while the orthorhombic single phase is obtained after calcination at 900 °C. During the sintering, the presence of the liquid K-rich phase due to the lower melting point has a significant impact on the densification, the abnormalmore » grain growth and the deteriorated piezoelectric properties. From the standpoint of piezoelectric properties, the optimal calcination temperature obtained for KNN ceramics calcined at this temperature is determined to be 800 °C, with piezoelectric constant d33=128.3 pC/N, planar electromechanical coupling coefficient kp=32.2%, mechanical quality factor Qm=88, and dielectric loss tan δ=2.1%.« less

  6. Improved magnetic properties of microwave processed Mn0.5Zn0.5Fe2O4 particles

    NASA Astrophysics Data System (ADS)

    Suneetha, T.; Kashyap, Subhash C.; Gupta, Hem C.

    2013-02-01

    Mn0.5Zn0.5Fe2O4 nanoparticles, first prepared by citrate precursor route, have been processed by two different methods to obtain polycrystalline samples. In one case the pressed pellets are processed in microwave H-field at 500 °C for different duration: 1, 3 and 5 min, and in another case the pellets are conventionally sintered at 500 °C for 180 min. The powder x-ray diffraction patterns confirmed the single cubic phase in the all samples. The scanning electron micrographs revealed the grain growth during microwave processing, with the particle size increasing to 1μm for the sample heated at 500 °C for 5 min, whereas the sintered samples had a particle size of ˜20 nm. A maximum saturation magnetization of 56 emu/g at room temperature was estimated by vibration sample magnetometer for this sample; where as conventional sintered sample has 24 emu/g. With microwave processing we can obtain microcrystalline samples with improved magnetization in a short span of 5 min.

  7. 30 CFR 5.10 - Purpose and scope.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.10 Purpose and scope... to process the application; (2) Clerical services, computer tracking and status reporting,...

  8. 30 CFR 5.10 - Purpose and scope.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.10 Purpose and scope... to process the application; (2) Clerical services, computer tracking and status reporting,...

  9. 30 CFR 5.10 - Purpose and scope.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.10 Purpose and scope... to process the application; (2) Clerical services, computer tracking and status reporting,...

  10. Compositional variations in In0.5Ga0.5N nanorods grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Cherns, D.; Webster, R. F.; Novikov, S. V.; Foxon, C. T.; Fischer, A. M.; Ponce, F. A.; Haigh, S. J.

    2014-05-01

    The composition of InxGa1 - xN nanorods grown by molecular beam epitaxy with nominal x = 0.5 has been mapped by electron microscopy using Z-contrast imaging and x-ray microanalysis. This shows a coherent and highly strained core-shell structure with a near-atomically sharp boundary between a Ga-rich shell (x ˜ 0.3) and an In-rich core (x ˜ 0.7), which itself has In- and Ga-rich platelets alternating along the growth axis. It is proposed that the shell and core regions are lateral and vertical growth sectors, with the core structure determined by spinodal decomposition.

  11. Design of Si0.5Ge0.5 based tunnel field effect transistor and its performance evaluation

    NASA Astrophysics Data System (ADS)

    Singh, Gurmeet; Amin, S. Intekhab; Anand, Sunny; Sarin, R. K.

    2016-04-01

    In this work, the performance comparison of two heterojunction PIN TFETs having Si channel and Si0.5Ge0.5 source with high-k (SiGe DGTFET HK) and hetero-gate dielectric (SiGe DGTFET HG) respectively with those of two homojunction Si based PIN (DGTFET HK and DGTFET HG) TFETs is performed. Similarly, by employing the technique of pocketing at source junction in above four PIN TFETs, the performances of resultant four PNPN TFETs (SiGe PNPN DGTFET HK, SiGe PNPN DGTFET HG, PNPN DGTFET HK and PNPN DGTFET HG) are also compared with each other. Due to lower tunnel resistance of SiGe based heterojunction PIN and PNPN TFETs, the DC parameters such as ON current, ON-OFF current ratio, average subthreshold slope are improved significantly as compared to Si based PIN and PNPN TFETs respectively. The output characteristics of HG architectures in Si based homojunction PIN and PNPN TFETs is observed to be identical to with respective Si based HK PIN and PNPN TFET architectures. However, the output characteristics of HG architectures in SiGe based heterojunction PIN and PNPN TFETs degrade as compared to their respective SiGe based HK PIN and PNPN TFET architectures. In ON state, SiGe based HK and HG PIN and PNPN TFETs have lower gate capacitance (Cgg) as compared to their respective Si based HK and HG PIN and PNPN TFETs. Moreover, HG architecture suppresses gate to drain capacitance (Cgd) and ambipolar conduction. Transconductance (gm) and cut off frequency (fT) is also observed to be higher for SiGe based PIN and PNPN TFETs.

  12. Possible radio emission from Uranus at 0.5 MHz

    NASA Technical Reports Server (NTRS)

    Brown, L. W.

    1976-01-01

    Radio emission from the direction of Uranus has been detected in data from the Goddard radio astronomy experiment on the IMP-6 spacecraft. Previously, emission from the direction of Jupiter and Saturn had been observed by IMP-6 at a number of frequencies near 1 MHz and were identified through an analysis of the phase of the observed modulated signal detected from the spinning dipole antenna. This technique was applied to the direction of Uranus with possible positive results. Over the approximately 500 days of data, three to six bursts with unique spectral characteristics have been found. The events persisted less than 3 minutes and are strongest in intensity near 0.5 MHz. Identification with Uranus is confused by the likely presence of low-level terrestrial and solar emission. Because of the unfavorable angular separation of earth and Uranus, there is a possibility that the bursts are atypical terrestrial magnetospheric phenomena, although the uniqueness of the set of events indicates the probable detection of radiation from Uranus.

  13. Initial oxidation kinetics and energetics of Cu 0.5Au 0.5 (0 0 1) film investigated by in situ ultrahigh vacuum transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Zhou, Guang-Wen; Eastman, Jeffrey A.; Yang, Judith C.

    2006-06-01

    The initial oxidation behavior of Cu 0.5Au 0.5 (0 0 1) thin film was investigated by in situ ultrahigh vacuum transmission electron microscopy to model nano-oxidation of alloys with one active component and one noble component. The formation of irregular-shaped octahedron Cu 2O islands with cube-on-cube crystallographic orientation to the substrate film was observed at all temperature studied. The energetics of Cu 2O nucleation for Cu and Cu 0.5Au 0.5 oxidation was compared. Cu 0.5Au 0.5 oxidation has lower nucleation activation energy due to the reduced mismatch strain between Cu 2O and Cu 0.5Au 0.5 films. On the other hand, the reaction kinetics for Cu 0.5Au 0.5 alloy oxidation is slower due to the higher diffusion activation energy of Cu.

  14. Epitaxial La0.5Sr0.5CoO3 thin films: Structure, magnetism, and transport

    NASA Astrophysics Data System (ADS)

    Torija, M. A.; Sharma, M.; Fitzsimmons, M. R.; Varela, M.; Leighton, C.

    2008-07-01

    La1-xSrxCoO3 has received considerable attention in bulk form. This is due to interest in the fundamental magnetic properties (spin-state transitions and magnetic phase separation) as well as potential applications in ferroelectric memory and solid-oxide fuel cells. The structure and properties in thin film form are not well understood, and the influence of dimensional confinement on effects such as magnetic phase separation is unknown. Here, we report a comprehensive investigation of structure, magnetism, and transport in strained epitaxial La0.5Sr0.5CoO3 (001) films deposited on SrTiO3 (001) substrates by reactive dc magnetron sputtering. The crystalline quality, phase purity, strain state, oxygen stoichiometry, morphology, and magnetic and electronic properties of the epilayers are all probed and are found to be particularly sensitive to the total sputtering gas pressure and the ratio of reactive to inert gas (PO2/PAr). The various structure-property relationships are discussed in detail, particularly with respect to the degree of oxygenation and oxygen-induced resputtering. The films are strained and tetragonally distorted due to the 1.9% lattice mismatch with SrTiO3. Significant strain relaxation occurs at thicknesses around 200 Å, resulting in a crossover from two-dimensional-like to three-dimensional growth. Polarized neutron reflectometry was combined with x-ray reflectometry to obtain chemical and magnetic depth profiles, which are compared with cross-sectional scanning transmission electron microscopy. The results indicate a thin (˜10 Å) layer at the film/substrate interface with significantly different structural properties to the bulk of the film, as well as a strongly graded magnetic and chemical profile at the film surface due to the significant roughness. The Curie temperature was found to decrease very slowly as the thickness is reduced down to ˜50 Å, at which point a rapid decrease occurs, almost coincident with a sharp decrease in saturation

  15. Electric polarization of Sr0.5Ba0.5MnO3: a multiferroic Mott insulator

    NASA Astrophysics Data System (ADS)

    Nourafkan, Reza

    2015-03-01

    Multiferroics, materials which display simultaneous magnetic and ferroelectric orders, are interesting both for their rich physics and for their promising practical applications. The search for multiferroic materials with strong-magnetoelectric coupling is challenging and requires an understanding of how the magnetic order, or more specifically the correlations, influence the electric polarization and vice versa. A calculations of the electric polarization in the paramagnetic (PM) insulating phase of multiferroics is essential to address this mutual influence. Ab inito calculations of the electric polarization are based on the modern theory of polarization, which is a single-electron theory. Thus, a correlation driven insulating state is beyond the scope of this approach. Here we show that combining correlated band structure calculations (DFT+DMFT) with a formula for the electric polarization of interacting insulators, expressed in terms of the full Green and vertex functions, allows for the first time to reliably calculate the polarization in the PM phase. We focus on the Mott insulator Sr0.5Ba0.5MnO3, in which both magnetic and ferroelectric instabilities are related to the Mn ions. We predict a ferroelectric polarization of ~= 16 . 5 μC / cm2 in the high temperature paramagnetic phase and recover the measured value of ~= 13 . 3 μC / cm2 in the low temperature antiferromagnetic phase. Our calculations reveal that the the driving force behind the ferroelectric distortion comes from the tendency of Mn eg states to establish a stronger covalency with the surrounding oxygens. This covalency is reduced by correlations, in particular by Hund coupling. On the other hand, the half-filled Mn t2 g orbitals give rise to the magnetic ordering which decreases the ionic displacement, hence its contribution to the polarization. For fixed ionic displacement, the magnetic order also slightly decreases the electronic contribution to the electric polarization by partially

  16. Upper critical fields in a FeSe0.5Te0.5 superconducting single crystal

    NASA Astrophysics Data System (ADS)

    Velasco-Soto, D.; Rivera-Gómez, F. J.; Santillán-Rodríguez, C. R.; Sáenz-Hernández, R. J.; Botello-Zubiate, M. E.; Matutes Aquino, J. A.

    2013-05-01

    A single crystal with a nominal composition FeSe0.5Te0.5 was obtained by the Bridgman method. A quartz ampulla with the sample inside was vacuum-sealed and maintained at 1050 °C for 37 h to homogenize the sample. Subsequently, the quartz ampulla with the sample was moved with a speed of 2.2 mm/h to a furnace which was at 450 °C. X-ray diffraction confirmed the tetragonal structure of the grown single crystal with the cleavage plane corresponding to the ab plane. Resistance measurements were carried out with magnetic fields from 0 to 9 T, applied parallel to the c axis and ab plane, respectively. A zero-field critical temperature Tc = 14 K was determined. The upper critical field vs. temperature phase diagram was built for temperatures where the resistance drops to 90%, 50%, and 10% of the normal state resistance. The linear extrapolation to T = 0 K gave upper critical fields of 57.2, 51.8, and 46.0 T for Hǁc axis and 109.6, 95.5, and 80.9 T for Hǁab. Applying the Werthamer-Helfand-Hohenberg (WHH) theory, upper critical fields of 39.6, 35.9, and 31.8 T and coherence lengths of 28.8, 30.3, and 32.1 Å were obtained for Hǁc; while for Hǁab, upper critical fields of 51.3, 40.7, and 37.5 T and coherence lengths of 22.3, 26.7, and 31.5 Å were obtained. The value of μ0Hc2/kBTc calculated by the WHH theory exceeds the Pauli limit (1.84 T/K) indicating the unconventional nature of superconductivity. The activation energy U0 has two different rates of change with the applied magnetic field probably due to two different thermal activation mechanisms; the origin of which requires further investigation. A similar behavior is observed in the irreversibility lines.

  17. Crystal structure, oxidation state and magnetism of SrxLa2-xCu0.5Ru0.5O4 (x=1, 1.5)

    NASA Astrophysics Data System (ADS)

    Lü, Minfeng; Deng, Xiaolong; Waerenborgh, João C.; Wu, Xiaojie; Meng, Jian

    2014-03-01

    SrxLa2-xCu0.5Ru0.5O4 (x=1, 1.5) oxides with K2NiF4-type structure were prepared by solid state reaction and characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, magnetic and electrical resistivity measurements. The SrLaCu0.5Ru0.5O4 phase was obtained for the first time with a negligible amount of impurities. The octahedral Cu/RuO6 units are more elongated in SrLaCu0.5Ru0.5O4 than in Sr1.5La0.5Cu0.5Ru0.5O4 indicating a greater extent of static Jahn-Teller distortion. XPS suggests that mixed ion pairs Ru5+/Ru4+↔Cu+/Cu2+ are present in SrLaCu0.5Ru0.5O4, while Ru remains as Ru5+ and Cu as Cu2+ in Sr1.5La0.5Cu0.5Ru0.5O4. Both samples show spin-glass behavior, which can be explained by competition between ferromagnetic and antiferromagnetic superexchange interactions. The negative Weiss temperature estimated for SrLaCu0.5Ru0.5O4, -318 K, is significantly lower than -11.5 K deduced for Sr1.5La0.5Cu0.5Ru0.5O4 which may be related to the higher static Jahn-Teller distortion in the former oxide.

  18. Giant Dielectric Behavior of BaFe0.5Nb0.5O3 Perovskite Ceramic

    NASA Astrophysics Data System (ADS)

    Intatha, Uraiwan; Eitssayeam, Sukum; Tunkasiri, Tawee

    2009-12-01

    Single-phase cubic Ba(Fe,Nb)0.5O3 (BFN) powder was synthesized by solid-state reaction at 1443 K for 4 hour in air. X-ray diffraction indicated that the BFN oxide mixture calcined at 1200°C crystallizes to the pure cubic perovskite phase. BFN ceramics were produced from this powder by sintering at 1623-1673 K for 4 hrs in air. Samples prepared under these conditions achieved up to 94.7% of the theoretical density. The temperature dependence of their dielectric constant and loss tangent, measured at difference frequencies, shows an increase in the dielectric constant with temperature which is probably due to disorder on the B site ion of the perovskite. Non-Debye type of relaxation phenomena has been observed in the BFN ceramics as confirmed by Cole-Cole plots. The higher value of ɛ' at the lower frequency is explained on the basis of the Maxwell-Wagner (MW) polarization model.

  19. Giant Dielectric Behavior of BaFe0.5Nb0.5O3 Perovskite Ceramic

    NASA Astrophysics Data System (ADS)

    Intatha, Uraiwan; Eitssayeam, Sukum; Tunkasiri, Tawee

    Single-phase cubic Ba(Fe,Nb)0.5O3 (BFN) powder was synthesized by solid-state reaction at 1443 K for 4 hour in air. X-ray diffraction indicated that the BFN oxide mixture calcined at 1200°C crystallizes to the pure cubic perovskite phase. BFN ceramics were produced from this powder by sintering at 1623-1673 K for 4 hrs in air. Samples prepared under these conditions achieved up to 94.7% of the theoretical density. The temperature dependence of their dielectric constant and loss tangent, measured at difference frequencies, shows an increase in the dielectric constant with temperature which is probably due to disorder on the B site ion of the perovskite. Non-Debye type of relaxation phenomena has been observed in the BFN ceramics as confirmed by Cole-Cole plots. The higher value of ɛ‧ at the lower frequency is explained on the basis of the Maxwell-Wagner (MW) polarization model.

  20. Defect distribution and compositional inhomogeneities in Al0.5Ga0.5N layers grown on stepped surfaces

    NASA Astrophysics Data System (ADS)

    Mogilatenko, A.; Knauer, A.; Zeimer, U.; Weyers, M.

    2016-02-01

    This study reports on defect distribution and compositional homogeneity of Al x Ga1-x N layers with a nominal composition x of 0.5 grown on AlN by metal organic vapor phase epitaxy. The AlN layers with a low threading dislocation density (TDD) of a few 108 cm-2 were obtained by ELO and showed periodic surface macrosteps. Al x Ga1-x N growth on these AlN surfaces results in inhomogeneous Ga distribution due to enhanced Ga incorporation on the macrostep sidewalls. Variation of AlGaN deposition rate strongly influences the Ga distribution as well as the defect structure in the layers. Low growth rates (0.2 μm h-1) result in an inhomogeneous TD distribution with formation of alternating stripes with lower and higher defect densities. Additionally, self-organized formation of additional Ga-rich areas at the top edge of the steps is observed. In contrast, at a higher growth rate of 1 μm h-1 the formation of additional Ga-rich areas can be completely suppressed, but the defect density increases. This leads to an optimum growth rate to minimize the TDD.

  1. 129I AMS at 0.5 MV tandem accelerator

    NASA Astrophysics Data System (ADS)

    Alfimov, Vasily; Synal, Hans-Arno

    2010-04-01

    The 129I measurement program has been established at the 0.5 MV 'Tandy' accelerator of the PSI/ETH Zürich AMS facility. This development was made possible by using a SiN window instead of Mylar one in a gas ionization detector. The setting up of the 129I measurement at Tandy is simple, the acquired performance is stable and reliable, and the quality of results is equal to or better than at our larger EN-tandem. With this setup, high sample throughput, which is required in many 129I studies, can be easily achieved. The measurements are performed in the +3 charge state. At this charge state the major difficulty in the 129I +3 identification is caused by a highly abundant 43 +1 ( m = 43, q = +1) molecule interference. This is a positive molecular ion, because its intensity reduces exponentially with an increase in gas stripper pressure. We conclude that this molecule is 27Al 16O + ( m/ q = 43/1 = 129/3) and comes from the break-up of (Al 2O 3 + Al) - ( m = 129) precursor at the terminal: (Al 2O 3 + Al) - → 27Al 16O +. The expected isobaric interferences 43Ca +1 and 86Sr +2, which also originate from the break-up of molecules in the stripper, were found to be low and do not disturb the 129I +3 measurements. The best repeatable performance with our standard sample material was achieved at 0.14 μg/cm 2 Ar gas stripper pressure with machine blanks showing ˜6 × 10 -14 normalized 129I/I ratio and 9% transmission through the accelerator. However, high 27Al 16O + molecular rates were observed from the user samples, and in order to destroy these molecules we had to increase the stripper pressure to ˜0.22 μg/cm 2. This increase in the stripper pressure degraded the machine blank values to ˜9 × 10 -14 and reduced transmission to 8%. Nevertheless, the achieved measurement conditions are sufficient for measurement of nearly all 129I samples that have been submitted to PSI/ETH over the last few years.

  2. First-principles investigations on thermodynamic properties of the ordered and disordered Si0.5Ge0.5 alloys

    NASA Astrophysics Data System (ADS)

    Zhu, Yan; Zhang, Xinyu; Zhang, Suhong; Sun, Xiaowei; Wang, Limin; Ma, Mingzhen; Liu, Riping

    2014-05-01

    The structure, formation energy, and thermodynamic properties of Si0.5Ge0.5 alloys are investigated through first-principles method. The ordered and disordered structures of Si0.5Ge0.5 compounds are considered. Our results show that thermodynamic instabilities of Si0.5Ge0.5 alloys at 0 K can be judged from the calculated formation energy. However, the alloy might be prepared at specified environment owing to the entropy effects considered. Moreover, the temperature dependence of the heat capacity, Debye temperature and thermal expansion coefficient of ordered and disordered structures are discussed.

  3. X-ray photoelectron spectroscopic study of direct reforming catalysts Ln0.5Sr0.5Ti0.5Mn0.5O3±d (Ln = La, Nd, and Sm) for high temperature-operating solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Kim, Keunsoo; Jeong, Jihoon; Azad, Abul K.; Jin, Sang Beom; Kim, Jung Hyun

    2016-03-01

    Chemical states of lanthanide doped perovskite for direct reforming anode catalysts, Ln0.5Sr0.5Ti0.5Mn0.5O3±d (Ln = La, Nd, and Sm) have been studied by X-ray Photoelectron Spectroscopy (XPS) in order to determine the effects of various lanthanide substitution in complex perovskites for high temperature-operating solid oxide fuel cells (HT-SOFC). The charge state of lanthanide ions remained at 3+ and the binding energies of the lanthanide ions in Ln0.5Sr0.5Ti0.5Mn0.5O3±d were located in a relatively lower range compared to those of conventional lanthanide oxides. Mn and Ti were regarded as charge compensation components in Ln0.5Sr0.5Ti0.5Mn0.5O3±d; Mn was more influential than Ti. In the cases of substituting Nd and Sm into Ln0.5Sr0.5Ti0.5Mn0.5O3±d, some portion of Ti showed metallic behavior; the specific Mn satellite peak indicating an electro-catalytic effect had occurred. Three types of oxygen species comprised of lattice oxygen, carbonate species, and adsorbed oxygen species were observed in Ln0.5Sr0.5Ti0.5Mn0.5O3±d from the O 1s spectra; a high portion of lattice oxygen was observed in both Nd0.5Sr0.5Ti0.5Mn0.5O3±d (NSTM) and Sm0.5Sr0.5Ti0.5Mn0.5O3±d (SSTM). In various respects, NSTM and SSTM will be desirable reforming catalysts and anode candidates for high temperature solid oxide fuel cell.

  4. Structure and dielectric properties of Na0.5Bi0.5TiO3-CaTiO3 solid solutions

    NASA Astrophysics Data System (ADS)

    Birks, E.; Dunce, M.; Ignatans, R.; Kuzmin, A.; Plaude, A.; Antonova, M.; Kundzins, K.; Sternberg, A.

    2016-02-01

    Despite wide studies of Na0.5Bi0.5TiO3, structure of this material and its connection with the observed physical properties still raise numerous questions due to mutually contradicting results obtained. Here, structure and dielectric properties of poled and unpoled Na0.5Bi0.5TiO3-CaTiO3 solid solutions are studied, projecting the obtained concentration dependence of structure and dielectric properties on pure Na0.5Bi0.5TiO3 as the end member of this material group. X-ray diffraction patterns for Na0.5Bi0.5TiO3-CaTiO3 solid solutions reveal dominating of an orthorhombic Pnma phase, even for the compositions approaching the end composition (Na0.5Bi0.5TiO3), whereas structure of pure Na0.5Bi0.5TiO3 can be considered, assuming coexistence of rhombohedral and orthorhombic phases. This allows one to avoid appearance of a large difference of rhombohedral distortions between the unpoled and poled Na0.5Bi0.5TiO3, if the rhombohedral distortion is calculated as for single R3c phase. Features of dielectric permittivity, corresponding to the observed structural phase transition, are identified. It is discussed that the rhombohedral R3c phase is responsible for appearance of the frequency-dependent shoulder of dielectric permittivity temperature dependence, characteristic for unpoled Na0.5Bi0.5TiO3.

  5. One-dimensional SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers and enhancement magnetic property.

    PubMed

    Song, Fuzhan; Shen, Xiangqian; Liu, Mingquan; Xiang, Jun

    2011-08-01

    SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers of diameters about 100 nm with mass ratio 1:1 have been prepared by the electrospinning and calcination process. The SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrites are formed after calcined at 700 degrees C for 2 hours. The composite ferrite nanofibers are fabricated from nanosized Ni(0.5)Zn(0.5)Fe2O4 and SrFe12O19 ferrite grains with a uniform phase distribution. The ferrite grain size increases from about 11 to 36 nm for Ni(0.5)Zn(0.5)Fe12O4 and 24 to 56 nm for SrFe12O19 with the calcination temperature increasing from 700 to 1100 degrees C. With the ferrite grain size increasing, the coercivity (Hc) and remanence (Mr) for the SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers initially increase, reaching a maximum value of 118.4 kA/m and 31.5 Am2/kg at the grain size about 40 nm (SrFe12O19) and 24 nm (Ni(0.5)Zn(0.5)Fe2O4) respectively, and then show a reduction tendency with a further increase of the ferrite grain size. The specific saturation magnetization (Msh) of 63.2 Am2/kg for the SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers obtained at 900 degrees C for 2 hours locates between that for the single SrFe12O19 ferrite (48.5 Am2/kg) and the single Ni(0.5)Zn(0.5)Fe2O4 ferrite (69.3 Am2/kg). In particular, the Mr value 31.5 Am2/kg for the SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers is much higher than that for the individual SrFe12O19 (25.9 Am2/kg) and Ni(0.5)Zn(0.5)Fe2O4 ferrite (11.2 Am2/kg). These enhanced magnetic properties for the composite ferrite nanofibers can be attributed to the exchange-coupling interaction in the composite. PMID:22103109

  6. Superconductivity phase diagram of Se-substituted CeO0.5F0.5Bi(S1-xSex)2

    NASA Astrophysics Data System (ADS)

    Mizuguchi, Yoshikazu; Hiroi, Takafumi; Miura, Osuke

    2016-02-01

    We investigated the effects of Se substitution on the lattice constants and superconducting properties of CeO0.5F0.5Bi(S1-xSex)2. With increasing Se concentration, the a lattice constant increased, while the c lattice constant did not show any significant increase between x = 0.1 and x = 0.5. Bulk superconductivity was observed in samples with x = 0.2-0.4, and the superconducting transition temperature was the highest at x = 0.3. The obtained superconductivity phase diagram was compared to those of LaO0.5F0.5Bi(S1-xSex)2 and NdO0.5F0.5Bi(S1-xSex)2.

  7. (2,3,5,6-Tetra­fluoro­phenolato)[5,10,15,20-tetra­kis­(4-meth­oxy­phen­yl)porphyrinato]iron(III) cyclo­hexane monosolvate

    PubMed Central

    Xu, Nan; Powell, Douglas R.; Richter-Addo, George B.

    2013-01-01

    The title compound, [Fe(C6HF4O)(C48H36N4O4)]·C6H12, represents a five-coordinate iron(III) porphyrin complex in a square-pyramidal geometry with a tetra­fluoro­phenolate anion as the axial ligand. The FeIII atom is displaced by 0.364 (2) Å from the 24-atom mean plane of the porphyrinate ring towards the tetra­fluoro phenolate anion. The average Fe—N distance is 2.053 (2) Å and the Fe—O distance is 1.883 (2) Å. A porphyrin aryl H atom points in the general direction of the phenoxide ring. The mean plane separation between the 24-atom porphyrin planes of two adjacent porphyrin rings is ∼3.7 Å, and the lateral shift is ∼3.5 Å resu, ting in an Fe⋯Fe separation of 5.6167 (14) Å. PMID:24098166

  8. 21 CFR 73.3117 - 16,23-Dihydrodinaphtho[2,3-a:2′,3′-i] naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... paragraph (a) of this section may be used as a color additive in contact lenses in amounts not to exceed the... Federal Food, Drug, and Cosmetic Act with respect to the contact lens in which the color additive is...

  9. 21 CFR 73.3117 - 16,23-Dihydrodinaphtho[2,3-a:2′,3′-i] naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Federal Food, Drug, and Cosmetic Act with respect to the contact lens in which the color additive is used... paragraph (a) of this section may be used as a color additive in contact lenses in amounts not to exceed...

  10. 21 CFR 73.3117 - 16,23-Dihydrodinaphtho[2,3-a:2′,3′-i] naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Federal Food, Drug, and Cosmetic Act with respect to the contact lens in which the color additive is used... paragraph (a) of this section may be used as a color additive in contact lenses in amounts not to exceed...

  11. Artificial layered perovskite oxides A(B{sub 0.5}B′{sub 0.5})O{sub 3} as potential solar energy conversion materials

    SciTech Connect

    Chen, Hungru; Umezawa, Naoto

    2015-02-07

    Perovskite oxides with a d{sup 0} electronic configuration are promising photocatalysts and exhibit high electron mobilities. However, their band gaps are too large for efficient solar energy conversion. On the other hand, transition metal cations with partially filled d{sup n} electronic configurations give rise to visible light absorption. In this study, by using hybrid density functional theory calculations, it is demonstrated that the virtues of the two categories of materials can be combined in perovskite oxide A(B{sub 0.5}B′{sub 0.5})O{sub 3} with a layered B-site ordering along the [001] direction. The electronic structures of the four selected perovskite oxide compounds, La(Ti{sub 0.5}Ni{sub 0.5})O{sub 3}, La(Ti{sub 0.5}Zn{sub 0.5})O{sub 3}, Sr(Nb{sub 0.5}Cr{sub 0.5})O{sub 3}, and Sr(Nb{sub 0.5}Fe{sub 0.5})O{sub 3} are calculated and discussed.

  12. 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

  13. Electron-phonon superconductivity in LaO{sub 0.5}F{sub 0.5}BiSe{sub 2}

    SciTech Connect

    Feng, Yanqing; Du, Yongping; Wan, Xiangang Wang, Bogen; Ding, Hang-Chen; Savrasov, Sergey Y.; Duan, Chun-Gang

    2014-06-21

    We report density functional calculations of the electronic structure, Fermi surface, phonon spectrum and electron–phonon coupling for the newly discovered superconductor LaO{sub 0.5}F{sub 0.5}BiSe{sub 2}. It is confirmed that there is a strong Fermi surface nesting at (π,π,0), which results in unstable phonon branches. Combining the frozen phonon total energy calculations and an anharmonic oscillator model, we find that the quantum fluctuation prevents the appearance of static long–range order. The calculation shows that LaO{sub 0.5}F{sub 0.5}BiSe{sub 2} is highly anisotropic, and same as its cousin LaO{sub 0.5}F{sub 0.5}BiS{sub 2}, this compound is also a conventional electron-phonon coupling induced superconductor.

  14. Effect of annealing temperature on photoelectrochemical properties of nanocrystalline MoBi2(Se0.5Te0.5)5 thin films

    NASA Astrophysics Data System (ADS)

    Salunkhe, Manauti; Pawar, Nita; Patil, P. S.; Bhosale, P. N.

    2014-10-01

    Nanocrystalline MoBi2(Se0.5Te0.5)5 thermoelectric thin films have been deposited on ultrasonically cleaned glass and FTO-coated glass substrates by Arrested Precipitation Technique. The change in properties of MoBi2(Se0.5Te0.5)5 thin films were examined after annealing at the temperature 473 K for 3 h. The structural, morphological, compositional and electrical properties of thin films were characterized by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, etc. Thermoelectric properties of the thin films have been evaluated by measurements of electrical conductivity and Seebeck coefficient in the temperature range 300-500 K. Our aim is to investigate the effect of annealing on behaviour of MoBi2(Se0.5Te0.5)5 thin films along with photoelectrochemical properties.

  15. Influence of Co doping on structural and electrical properties of La0.5Ce0.5Mn1-xCoxO3 manganites

    NASA Astrophysics Data System (ADS)

    Mansuri, Irfan; Shaikh, M. W.; Kuo, Y. K.; Varshney, Dinesh

    2013-02-01

    The effect of Co doping on structural, electrical and magnetic properties of half doped La0.5Ce0.5Mn1-xCoxO3 (x = 0, 0.05) is investigated. The structure of the compounds crystallizes in to orthorhombically distorted perovskite structure. The electrical resistivity of La0.5Ce0.5MnO3 exhibits metal-semiconductor transition (TMS ˜ 225 K). However, La0.5Ce0.5Mn1-xCo0.05O3 manganites show semiconducting behavior throughout temperature range. The magnetic susceptibility measurement confirms that both the samples undergo a transition from paramagnetic to ferromagnetic phase. The metallic resistivity (T < TMS) is analyzed by considering the electron-electron, electron-phonon and spin fluctuation mechanism while semiconducting resistivity is fitted with small polaron conduction model.

  16. Degenerate rhombohedral and orthorhombic states in Ca-substituted Na0.5Bi0.5TiO3

    NASA Astrophysics Data System (ADS)

    Ranjan, Rajeev; Kothai, V.; Garg, Rohini; Agrawal, Anupriya; Senyshyn, Anatoliy; Boysen, Hans

    2009-07-01

    Neutron powder diffraction and temperature dependent dielectric studies were carried out on Ca-substituted Na0.5Bi0.5TiO3, i.e., (Na0.5Bi0.5)1-xCaxTiO3. Stabilization of an orthorhombic phase even at a low Ca concentration (0.050.5Bi0.5TiO3 (NBT) is susceptible to orthorhombic distortion. The orthorhombic and rhombohedral phases coexist for x =0.10, suggesting these phases to be nearly degenerate. The orthorhombic distortion favoring tendency of Ca assists in promoting the inherent instability with regard to this structure in pure NBT, which was reported recently.

  17. Transport and photoresponse properties in Pr0.5Ca0.5CoO3/Nb-SrTiO3 heterostructure

    NASA Astrophysics Data System (ADS)

    Zhao, S. G.; Gu, A.; Yan, X. L.; Hao, L. M.; Xie, Y.; Zhang, T.; Jin, K. X.

    2015-01-01

    Transport and photoresponse properties of the heterostructure consisting of a Pr0.5Ca0.5CoO3 film and a Nb-SrTiO3 substrate were investigated. The Pr0.5Ca0.5CoO3 film exhibits semiconducting behavior and the resistances are decreased when irradiated by a 532 nm laser. The rectifying behaviors are observed in the heterostructure. The ideality factors and the diffusion voltages monotonically decrease with increasing the temperature. The photovoltatges of the heterostructure under the irradiation approach the saturation at about 8.5 \\text{mW/mm}2 . The minority carrier lifetime of τp=0.281 \\text{s} is estimated from the time response properties in the falling process of photovoltages. These results reveal that the Pr0.5Ca0.5CoO3 heterostructures have great potentials in photoresponse and photoelectric conversion applications.

  18. (Y0.5In0.5)Ba(Co,Zn)4O7 cathodes with superior high-temperature phase stability for solid oxide fuel cells

    SciTech Connect

    Young Nam, Kim; Kim, Jung-Hyun; Paranthaman, Mariappan Parans; Manthiram, Arumugam; Huq, Ashfia

    2012-01-01

    (Y0.5In0.5)BaCo4-xZnxO7 (1.0 x 2.0) oxides crystallizing in a trigonal P31c structure have been synthesized and explored as cathode materials for solid oxide fuel cells (SOFC). At a given Zn content, the (Y0.5In0.5)BaCo4-xZnxO7 sample with 50 % Y and 50 % In exhibits much improved phase stability at intermediate temperatures (600 - 800 oC) compared to the samples with 100 % Y or In. However, the substitution of Zn for Co in (Y0.5In0.5)Ba(Co4-xZnx)O7 (1.0 x 2.0) decreases the amount of oxygen loss on heating, total electrical conductivity, and cathode performance in SOFC while providing good long-term phase stability at high temperatures. Among the various chemical compositions investigated in the (Y0.5In0.5)Ba(Co4-xZnx)O7 system, the (Y0.5In0.5)BaCo3ZnO7 sample offers a combination of good electrochemical performance and low thermal expansion coefficient (TEC) while maintaining superior phase stability at 600 800 oC for 100 h. Fuel cell performances of the (Y0.5In0.5)Ba(Co3Zn)O7 + Ce0.8Gd0.2O1.9 (GDC) (50 : 50 wt. %) composite cathodes collected with anode-supported single cell reveal a maximum power density value of 521 mW cm-2 at 700 oC.

  19. Distortional phase transitions accompanying spin reorientation in the intermetallide Tb/sub 0. 5/Nd/sub 0. 5/Fe/sub 2/

    SciTech Connect

    Ilyushin, A.S.; Kakhadze, S.O.; Makhmud, I.A.

    1988-01-01

    The thermal expansion and spin reorientation in the intermetallide Tb/sub 0.5/Nd/sub 0.5/Fe/sub 2/ at temperatures ranging from 4.2 to 300/sup 0/K were studied by the method of low-temperature x-ray diffractometry. It was established that with spin reorientation in Tb/sub 0.5/Nd/sub 0.5/Fe/sub 2/ the orientation of the magnetic moment vector changes from <111> to <110> with the formation of corner magnetic phases.

  20. Structural and electrical properties of 1 − x(Na{sub 0.5}K{sub 0.5})NbO{sub 3}–x(Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} ceramics

    SciTech Connect

    Lee, Tae-Ho; Lee, Sung-Gap Yeo, Jin-Ho; Jung, Hye-Rin

    2014-10-15

    Highlights: • We fabricated lead-free (Na{sub 0.5}K{sub 0.5})NbO{sub 3} ceramics. • We studied the structural and electrical properties of 1 − x(Na{sub 0.5}K{sub 0.5})NbO{sub 3}–x(Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} ceramics. • The structural and electrical properties improved with increasing amount of (Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3}. - Abstract: In this study, 1 − x(Na{sub 0.5}K{sub 0.5})NbO{sub 3}–x(Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} ceramics were fabricated using the conventional mixed oxide method. The effects of the addition of (Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} on the structural and electrical properties of the specimens were investigated for their application in piezoelectric devices. As the results of X-ray diffraction analysis show, all specimens display the typical polycrystalline perovskite structure without the presence of the second phase. Sintered densities increased with an increase in the amount of (Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} added and the specimen with 0.08 mol% of (Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} added showed the maximum value of 4.54 g/cm{sup 3}. Both average grain size and densification increased with an increase in the amount of (Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3}. The electromechanical coupling factor, dielectric constant ϵ{sub r}, dielectric loss tan δ, d{sub 33} and Curie temperature of the 0.92(Na{sub 0.5}K{sub 0.5})NbO{sub 3}–0.08(Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} specimens doped with 0.08 mol% of (Sr{sub 0.5}Ca{sub 0.5})TiO{sub 3} were 0.31, 1338, 0.021, 138 and 445 °C, respectively.

  1. Fully gapped superconductivity in In-doped topological crystalline insulator Pb0.5Sn0.5Te

    SciTech Connect

    Du, Guan; Gu, G. D.; Du, Zengyi; Fang, Delong; Yang, Huan; Zhong, R. D.; Schneeloch, J.; Wen, Hai -Hu

    2015-07-27

    In this study, superconductors derived from topological insulators and topological crystalline insulators by chemical doping have long been considered to be candidates as topological superconductors. Pb0.5Sn0.5Te is a topological crystalline insulator with mirror symmetry protected surface states on (001)-, (011)-, and (111)-oriented surfaces. The superconductor (Pb0.5Sn0.5)0.7In0.3Te is produced by In doping in Pb0.5Sn0.5Te, and is thought to be a topological superconductor. Here we report scanning tunneling spectroscopy measurements of the superconducting state as well as the superconducting energy gap in (Pb0.5Sn0.5)0.7In0.3Te on a (001)-oriented surface. The spectrum can be well fitted by an anisotropic s-wave gap function of Δ = 0.72 + 0.18cos4θ meV using Dynes model. The results show that the superconductor seems to be a fully gapped one without any in-gap states, in contradiction with the expectation of a topological superconductor.

  2. Transition metal redox and Mn disproportional reaction in LiMn0.5Fe0.5PO4 electrodes cycled with aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Zhuo, Zengqing; Hu, Jiangtao; Duan, Yandong; Yang, Wanli; Pan, Feng

    2016-07-01

    We performed soft x-ray absorption spectroscopy (sXAS) and a quantitative analysis of the transition metal redox in the LiMn0.5Fe0.5PO4 electrodes upon electrochemical cycling. In order to circumvent the complication of the surface reactions with organic electrolyte at high potential, the LiMn0.5Fe0.5PO4 electrodes are cycled with aqueous electrolyte. The analysis of the transitional metal L-edge spectra allows a quantitative determination of the redox evolution of Mn and Fe during the electrochemical cycling. The sXAS analysis reveals the evolving Mn oxidation states in LiMn0.5Fe0.5PO4. We found that electrochemically inactive Mn2+ is formed on the electrode surface during cycling. Additionally, the signal indicates about 20% concentration of Mn4+ at the charged state, providing a strong experimental evidence of the disproportional reaction of Mn3+ to Mn2+ and Mn4+ on the surface of the charged LiMn0.5Fe0.5PO4 electrodes.

  3. Effect of rare-earth (Er and Gd) substitution on the magnetic and multiferroic properties of DyFe0.5Cr0.5O3.

    PubMed

    Sharma, Mohit K; Basu, Tathamay; Mukherjee, K; Sampathkumaran, E V

    2016-10-26

    We report the results of our investigations on the influence of partial substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic susceptibility and heat capacity data, apart from confirming the occurrence of magnetic transitions at ~121 and 13 K in DyFe0.5Cr0.5O3, bring out that the lower transition temperature only is suppressed by rare-earth substitution. Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln  =  Er and Gd). There is an evidence for magnetoelectric coupling in all these materials with qualitative differences in its behavior as the temperature is changed across these two transitions. Remnant electric polarization is observed for all the compounds. The most notable observation is that electric polarization is seen to get enhanced as a result of rare-earth substitution with respect to that in DyFe0.5Cr0.5O3. Interestingly, a similar trend is seen in the magnetocaloric effect, consistent with the existence of magnetoelectric coupling. The results thus provide evidence for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides. PMID:27588356

  4. Research on Cs activation mechanism for Ga0.5Al0.5As(0 0 1) and GaN(0 0 0 1) surface

    NASA Astrophysics Data System (ADS)

    Shen, Yang; Chen, Liang; Qian, Yunsheng; Dong, Yanyan; Zhang, Shuqin; Wang, Meishan

    2015-01-01

    Based on first-principle density functional theory (DFT), plane wave with ultrasoft pseudopotential method was used to calculate and compare the Cs activation mechanism for Ga0.5Al0.5As(0 0 1) surface and GaN(0 0 0 1) surface. In this work, eight possible Cs adsorption sites are chosen for the Ga0.5Al0.5As(0 0 1) surface while five high-symmetry sites are considered in the calculation model of GaN(0 0 0 1) surface. Results show that Cs adsorption lowers the surface work function and benefits to get the most stable adsorption sites. Then dipole moment with different Cs coverage on two surfaces is investigated. The dipole moment decreases with the increase of Cs coverage and GaN(0 0 0 1) surface changes more obviously than Ga0.5Al0.5As(0 0 1) surface. The repulsion between Cs atomic dipole-dipole is enhanced and it causes depolarization and work function rising again. Finally, an activation experiment is performed to verify the result of our calculations, GaN photocathodes gets the minimum work function earlier than Ga0.5Al0.5As photocathodes.

  5. Thermal Conductivities and Thermal Expansion Coefficients of (Sm0.5Gd0.5)2(Ce1- x Zr x )2O7 Ceramics

    NASA Astrophysics Data System (ADS)

    Hongsong, Zhang; Lei, Shi; Yongde, Zhao; Gang, Li; Zhenjun, Li

    2015-09-01

    The (Sm0.5Gd0.5)2(Ce1- x Zr x )2O7 oxides were prepared by solid-state reaction, and their phase compositions, microstructures, and thermophysical properties were investigated. Results of x-ray diffraction reveal that pure (Sm0.5Gd0.5)2(Ce1- x Zr x )2O7 oxides with fluorite structure are successfully synthesized in the current study. The thermal expansion coefficient decreases with increasing content of ZrO2, which is higher than that of 7 wt.% yttria-stabilized zirconia (YSZ). The substitution of Zr4+ for Ce4+ reduces the thermal conductivity of Sm2Ce2O7 oxide. The thermal conductivity decreases from 1.69 W/m K ( x = 0) to 1.22 W/m K ( x = 0.3) at 1000 °C. The composition with x = 0.3 exhibits the lowest thermal conductivity at all temperatures, and the thermal conductivity of (Sm0.5Gd0.5)2 (Ce1- x Zr x )2O7 ceramics was obviously lower than those of fully dense 7 wt.% YSZ. These results suggested promising potential applications of the (Sm0.5Gd0.5)2 (Ce1- x Zr x )2O7 ceramics for high-temperature thermal barrier coatings.

  6. Spectroscopic and photoluminescence characterization of Dy(3+) in Sr0.5Ca0.5TiO3 phosphor.

    PubMed

    Vidyadharan, Viji; Sreeja, E; Jose, Saritha K; Joseph, Cyriac; Unnikrishnan, N V; Biju, P R

    2016-02-01

    The spectroscopic and photoluminescence characteristics of trivalent dysprosium (Dy(3+))-doped Sr0.5Ca0.5TiO3 phosphor materials synthesized via solid-state reaction method were studied. The X-ray diffraction profile confirmed the orthorhombic perovskite structure of the prepared samples. Judd-Ofelt analysis was carried out to obtain the intensity parameters and predicted radiative properties of Sr0.5Ca0.5TiO3:2wt%Dy(3+). The photoluminescence spectrum of Dy(3+)-doped Sr0.5Ca0.5TiO3 showed three emission peaks at 481, 574 and 638 nm corresponding to (4)F9/2 →(6)H15/2, (4)F9/2 →(6)H13/2 and (4)F9/2 →(6)H11/2 transitions respectively. The variation of luminescence intensity with different excitation wavelengths and Dy(3+) concentrations is discussed. The decay profiles of (4)F9/2 excited levels of Dy(3+) ions show bi-exponential behaviour and also a decrease in average lifetime with increase in Dy(3+) concentration. Yellow to blue luminescence intensity ratio, CIE chromaticity co-ordinates and correlated color temperature were also calculated for different concentrations of Dy(3+)-doped Sr0.5Ca0.5TiO3 phosphor at different λex. PMID:26032295

  7. Structural, thermal and electrical conductivity characteristics of Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (Ln: La, Nd and Sm) complex perovskites as anode materials for solid oxide fuel cell

    SciTech Connect

    Jeong, Jihoon; Azad, Abul K.; Schlegl, Harald; Kim, Byungjun; Baek, Seung-Wook; Kim, Keunsoo; Kang, Hyunil; Kim, Jung Hyun

    2015-03-15

    The Ti and Mn replaced complex perovskites, Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (Ln: La, Nd and Sm), were reported as potential anode materials for high temperature-operating solid oxide fuel cells (HT-SOFCs). For the present research study, synthesis, crystallographic, thermal and electrical conductivity properties of Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} complex perovskites were investigated using X-ray diffraction (XRD), Rietveld method, thermogravimetric analysis (TGA) and electrical conductivity to apply these oxide materials for the HT-SOFC anode materials. XRD results showed that Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} oxide systems synthesized as single phases did not react with 8 mol% yttria stabilized zirconia (8YSZ) and 10 mol% Gd-doped cerium oxide (CGO91) up to 1500 °C and did not decompose under dry 3.9% hydrogen at 850 °C. The crystal structures of La{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (LSTM), Nd{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (NSTM) and Sm{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (SSTM) showed orthorhombic symmetry with the space group Pbnm and SSTM showed a more distorted structure. Thermogravimetric analysis (TGA) proved weight gains in these three sample occurred under oxidizing conditions and weight loss under reducing conditions. Electrical conductivity values of NSTM were higher than those of LSTM and SSTM under oxidizing and reducing conditions. - Graphical abstract: The B-site cations (Ti/Mn) are surrounded by regular octahedra of oxygen in Nd{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d}(NSTM). These octahedra are linked together in a corner sharing three dimensional framework, while Nd/Sr ion occupies 12-coordinated A-site between these octahedra. The Ti/Mn–O{sub 6} octahedra are elongated along the c-axis. The crystal structure distortion was due to the smaller ionic radius of the A-site cations, which force the (Ti

  8. Effect of impurity substitution on band structure and mass renormalization of the correlated FeTe0.5Se0.5 superconductor

    NASA Astrophysics Data System (ADS)

    Thirupathaiah, S.; Fink, J.; Maheshwari, P. K.; Kishore, V. V. Ravi; Liu, Z.-H.; Rienks, E. D. L.; Büchner, B.; Awana, V. P. S.; Sarma, D. D.

    2016-05-01

    Using angle-resolved photoemission spectroscopy (ARPES), we studied the effect of the impurity potential on the electronic structure of FeTe0.5Se0.5 superconductor by substituting 10% of Ni for Fe, which leads to an electron doping of the system. We could resolve three hole pockets near the zone center and an electron pocket near the zone corner in the case of FeTe0.5Se0.5 , whereas only two hole pockets near the zone center and an electron pocket near the zone corner are resolved in the case of Fe0.9Ni0.1Te0.5Se0.5 , suggesting that the hole pocket having predominantly the x y orbital character is very sensitive to the impurity scattering. Upon electron doping, the size of the hole pockets decreases and the size of the electron pockets increases as compared to the host compound. However, the observed changes in the size of the electron and hole pockets are not consistent with the rigid-band model. Moreover, the effective mass of the hole pockets is reduced near the zone center and of the electron pockets is increased near the zone corner in the doped Fe0.9Ni0.1Te0.5Se0.5 as compared to FeTe0.5Se0.5 . We refer these observations to the changes of the spectral function due to the effect of the impurity potential of the dopants.

  9. Structural and Mössbauer spectroscopy characterization of bulk and nanostructured TiFe0.5 Ni0.5/graphite compounds and their hydrides

    NASA Astrophysics Data System (ADS)

    Martínez, M. A. R.; André-Filho, J.; Félix, L. L.; Coaquira, J. A. H.; Garg, V. K.; Oliveira, A. C.; Mestnik-Filho, J.

    2015-06-01

    The structural and hyperfine properties of bulk TiFe0.5Ni0.5 intermetallic and ball-milled TiFe0.5Ni0.5/graphite compounds and their hydrides have been studied. The bulk and nanostructured TiFe0.5Ni0.5 compounds crystallize in the cubic crystal structure of CsCl (B2). After hydrogenation, the formation of hydrogen-poor phase (∝-phase) and hydride phase ( β-phase) have been determined for the bulk compound. However, the formation of the ∝-phase and the hydrogen-richest phase ( γ-phase) and other secondary phases have been determined for the ball-milled TiFe0.5Ni0.5/graphite sample. It has been determined that the ball-milled TiFe0.5Ni0.5/graphite sample presents a large amount of the γ-phase which indicates that the presence of graphite nearby nanostructured intermetallic grains enhances the absorption of hydrogen. Mossbauer results are consistent with the structural results. Meanwhile, no significant changes in the isomer shift (IS) value has been determined for the α-phase with respect to the intermetallic compound, a strong increase in the IS value has been determined for the β- and γ-phases with respect to the ∝-phase. That increase indicates a decrease of the s-electron density at the Fe nuclei due to the charge transfer from the metal to the nearby hydrogen atoms.

  10. A Gel-Polymer Sn-C/LiMn0.5Fe0.5PO4 Battery Using a Fluorine-Free Salt.

    PubMed

    Di Lecce, Daniele; Fasciani, Chiara; Scrosati, Bruno; Hassoun, Jusef

    2015-09-30

    Safety and environmental issues, because of the contemporary use of common liquid electrolytes, fluorinated salts, and LiCoO2-based cathodes in commercial Li-ion batteries, might be efficiently mitigated by employing alternative gel-polymer battery configurations and new electrode materials. Herein we study a lithium-ion polymer cell formed by combining a LiMn0.5Fe0.5PO4 olivine cathode, prepared by simple solvothermal pathway, a nanostructured Sn-C anode, and a LiBOB-containing PVdF-based gel electrolyte. The polymer electrolyte, here analyzed in terms of electrochemical stability by impedance spectroscopy (EIS) and voltammetry, reveals full compatibility for cell application. The LiBOB electrolyte salt and the electrochemically delithiaded Mn0.5Fe0.5PO4 have a higher thermal stability compared to conventional LiPF6 and Li0.5CoO2, as confirmed by thermogravimetric analysis (TGA) and by galvanostatic cycling at high temperature. LiMn0.5Fe0.5PO4 and Sn-C, showing in lithium half-cell a capacity of about 120 and 350 mAh g(-1), respectively, within the gelled electrolyte configuration are combined in a full Li-ion polymer battery delivering a stable capacity of about 110 mAh g(-1), with working voltage ranging from 2.8 to 3.6 V. PMID:26348604

  11. Characterization of Cu3P phase in Sn3.0Ag0.5Cu0.5P/Cu solder joints

    NASA Astrophysics Data System (ADS)

    Chen, Jian-xun; Zhao, Xing-ke; Zou, Xu-chen; Huang, Ji-hua; Hu, Hai-chun; Luo, Hai-lian

    2014-01-01

    This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.5Cu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interfacial microstructure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like Cu3P phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear testing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.

  12. Effect of Zn2+ Substitution on the Structure and Magnetic Properties of Co0.5Cu0.5Fe2O4 Synthesized by Solvothermal Method

    NASA Astrophysics Data System (ADS)

    Huang, Xusheng; Zhou, Yuan; Wu, Wenwei; Xu, Jiawei; Liu, Shangqian; Liu, Dongsheng; Wu, Juan

    2016-06-01

    A series of Zn2+ doped Co-Cu ferrites with the formula Co0.5Cu0.5- x Zn x Fe2O4 (0.0 ≤ x ≤ 0.3) have been successfully synthesized using the solvothermal method. X-ray diffraction and scanning electron microscopy results indicate that a high-crystallized cubic Co0.5Cu0.5- x Zn x Fe2O4 with rod-like structure is obtained when the precursor is calcined at 800°C in air for 3 h. The lattice parameters increase with the increase of Zn2+ additional amount, attributed to the larger ionic radius of the substituted ion Zn2+ than Cu2+ ionic radius. Zn2+ substitution can improve the magnetic properties of Co0.5Cu0.5- x Zn x Fe2O4. Co0.5Cu0.4Zn0.1Fe2O4 obtained at 800°C has the highest specific saturation magnetization (73.7 ± 0.9 emu/g) and magnetic moment (3.13 ± 0.04 B.M.).

  13. Temperature dependent structures and properties of Bi0.5Na0.5TiO3-based lead free piezoelectric composite.

    PubMed

    Zhang, Ji; Sun, Lei; Geng, Xiao-Yu; Zhang, Bin-Bin; Yuan, Guo-Liang; Zhang, Shan-Tao

    2016-07-01

    The thermal depolarization around 100 °C of the Bi0.5Na0.5TiO3-based piezoelectric solid solutions leads to the disappearance of macroscopic ferroelectric/piezoelectric properties and remains a long-standing obstacle for their actual applications. In this communication, we report lead-free piezoelectric composites of 0.94Bi0.5Na0.5TiO3-0.06BaTiO3:0.5ZnO (BNT-6BT:0.5ZnO, where 0.5 is the mole ratio of ZnO to BNT-6BT) with deferred thermal depolarization, which is experimentally confirmed by systematic temperature dependent dielectric, ferroelectric, piezoelectric measurements. Especially, based on temperature dependent X-ray diffraction measurements on unpoled and poled samples, thermal depolarization is confirmed to have no relationship with the structural phase transition, the possible mechanism for the deferred thermal depolarization is correlated with the ZnO-induced local electric field which can suppress the depolarization field. We believe our results may be helpful for understanding the origin of thermal depolarization in BNT-based piezoelectric materials, and thus provide an effective way to overcoming this obstacle. PMID:27334673

  14. La{sub 0.5}Sr{sub 0.5}TiO{sub 3} nanopowders prepared by the hydrothermal method

    SciTech Connect

    Putjuso, Thanin; Maensiri, Santi; Hunpratub, Sitchai; Swatsitang, Ekaphan

    2012-09-15

    Graphical abstract: LRTEM image of the single-phase La{sub 0.5}Sr{sub 0.5}TiO{sub 3} particles. It is seen from the figure that the product has a plate-like morphology with average particles sizes in the range of 100–300 nm. In addition, the SAED data taken from an individual particle (lower inset) shows the presence of sharp diffraction rings, which are indicative of polycrystalline La{sub 0.5}Sr{sub 0.5}TiO{sub 3} formation. The high-resolution TEM image (upper inset) shows for further confirmation of a crystalline structure of La{sub 0.5}Sr{sub 0.5}TiO{sub 3} powder. This image shows a clearly resolved crystalline domain with uniform interplanar spacing of 0.276 nm. Highlights: ► La{sub 0.5}Sr{sub 0.5}TiO{sub 3} nanopowder is prepared in 2 M KOH solution by hydrothermal method. ► The solution is heat treated at 220 °C for 24 h in air. ► LRTEM reveals a plate-like morphology of particle with average size of 100–300 nm. ► HRTEM image shows a crystalline domain with interplanar spacing of 0.276 nm. -- Abstract: La{sub 0.5}Sr{sub 0.5}TiO{sub 3} nanopowders were prepared by the hydrothermal method. The influence of processing parameters, including KOH concentration, reaction temperature and reaction time on the obtained products were studied. The structure and morphology of the obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD results show that pure phase La{sub 0.5}Sr{sub 0.5}TiO{sub 3} nanopowders can be successfully synthesized with 2 M KOH concentration at a low temperature of 220 °C for 24 h. In addition, the product has a plate-like shape with particle sizes in the range of 25–100 nm as estimated by TEM.

  15. Enhanced nanoscale resistive switching memory characteristics and switching mechanism using high-Ge-content Ge0.5Se0.5 solid electrolyte

    PubMed Central

    2012-01-01

    We demonstrate enhanced repeatable nanoscale bipolar resistive switching memory characteristics in Al/Cu/Ge0.5Se0.5/W, as compared with Al/Cu/Ge0.2Se0.8/W structures, including stable AC endurance (>105 cycles), larger average SET voltage (approximately 0.6 V), excellent data retention (>105 s) at 85°C, and a high resistance ratio (>104) with a current compliance of 8 μA and a small operation voltage of ±1.5 V. A small device size of 150 × 150 nm2 and a Cu nanofilament with a small diameter of 30 nm are both observed by high-resolution transmission electron microscope in the SET state. The GexSe1 − x solid electrolyte compositions are confirmed by both energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The switching mechanism relies on the smaller barrier heights for holes rather than for electrons; the positively charged Cuz+ ions (i.e., holes) migrate through the defects in the GexSe1 − x solid electrolytes during SET/RESET operations. Hence, the Cu nanofilament starts to grow at the Ge0.5Se0.5/W interface, and starts to dissolve at the Cu/Ge0.5Se0.5 interface, as illustrated in the energy band diagrams. Owing to both the higher barrier for hole injection at the Cu/Ge0.5Se0.5 interface than at the Cu/Ge0.2Se0.8 interface and greater thermal stability, the resistive switching memory characteristics of the Al/Cu/Ge0.5Se0.5/W are improved relative to the Al/Cu/Ge0.2Se0.8/W devices. The Al/Cu/Ge0.5Se0.5/W memory device can also be operated with a low current compliance of 1 nA, and hence, a low SET/RESET power of 0.61 nW/6.4 pW is achieved. In addition, a large memory size of 1,300 Pbit/in2 is achieved with a small nanofilament diameter of 0.25 Å for a small current compliance of 1 nA. PMID:23130908

  16. Synthesis and electrochemical assessment of Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} ceramics and derived composite electrolytes

    SciTech Connect

    Martins, Natércia C.T.; Rajesh, Surendran; Marques, Fernando M.B.

    2015-10-15

    Highlights: • Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} prepared for the first time through solid state reaction. • High energy milling needed to assist the ceramic route. • Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} is oxide-ion conductor in air and n-type conductor at low pO{sub 2}. • Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} decomposes slightly when exposed to alkaline carbonates. • Composites based on Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} show standard electrical performance. - Abstract: Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} was prepared for the first time through high temperature (1600 °C for 5 h) solid state reaction, after high energy milling to enhance the mechano-chemical interaction of precursor oxides (CeO{sub 2} and Yb{sub 2}O{sub 3}). Single phase formation was confirmed by powder X-ray diffraction. Impedance spectroscopy data obtained under wide temperature (300–800 °C) and oxygen partial pressure (0.21 to about 10{sup −25} atm) ranges indicates that this material exhibits predominant oxide-ion conductivity under oxidizing conditions while n-type electronic conductivity prevails at low oxygen partial pressure. The mixed oxide shows modest ionic conductivity (1.1 × 10{sup −3} S cm{sup −1} at 800 °C) with activation energy of 1.3 eV in the 600–800 °C temperature range. When combined with molten carbonates (Li{sub 2}CO{sub 3} + Na{sub 2}CO{sub 3}, 1:1 molar ratio) to produce composite electrolytes, Ce{sub 0.5}Yb{sub 0.5}O{sub 1.75} slightly decomposed. However, the composite electrical performance is still acceptable and closely matches the conductivity of similar materials (>0.1 S cm{sup −1} immediately above 500 °C)

  17. Microwave characterization of Pb1-xCaxFe0.5Nb0.5O3 multiferroics at X-band

    NASA Astrophysics Data System (ADS)

    Dhiman, Tanvi; Singh, Charanjeet; Puri, Maalti; Kaur, Harpreet; Kaur, Randeep; Bindra Narang, S.

    2015-10-01

    The microwave characteristics of Pb1- x Ca x Fe0.5Nb0.5O3 multiferroics ( x = 0.0, 0.4, 0.45, 0.5, 0.55, 0.6), have been investigated as a function of frequency and substitution. The results depict -13.99 dB reflection loss at 11.65 GHz in composition x = 0.6. Microwave absorption is enhanced with substitution of Ca2+ ions and undoped composition 0.0 behaves as electromagnetic shield. The model governing microwave absorption is discussed and different compositions for electromagnetic applications have been suggested.

  18. A mixed iron-manganese based pyrophosphate cathode, Na2Fe0.5Mn0.5P2O7, for rechargeable sodium ion batteries.

    PubMed

    Shakoor, Rana A; Park, Chan Sun; Raja, Arsalan A; Shin, Jaeho; Kahraman, Ramazan

    2016-02-01

    The development of secondary batteries based on abundant and cheap elements is vital. Among various alternatives to conventional lithium-ion batteries, sodium-ion batteries (SIBs) are promising due to the abundant resources and low cost of sodium. While there are many challenges associated with the SIB system, cathode is an important factor in determining the electrochemical performance of this battery system. Accordingly, ongoing research in the field of SIBs is inclined towards the development of safe, cost effective cathode materials having improved performance. In particular, pyrophosphate cathodes have recently demonstrated decent electrochemical performance and thermal stability. Herein, we report the synthesis, electrochemical properties, and thermal behavior of a novel Na2Fe0.5Mn0.5P2O7 cathode for SIBs. The material was synthesized through a solid state process. The structural analysis reveals that the mixed substitution of manganese and iron has resulted in a triclinic crystal structure (P1[combining macron] space group). Galvanostatic charge/discharge measurements indicate that Na2Fe0.5Mn0.5P2O7 is electrochemically active with a reversible capacity of ∼80 mA h g(-1) at a C/20 rate with an average redox potential of 3.2 V. (vs. Na/Na(+)). It is noticed that 84% of initial capacity is preserved over 90 cycles showing promising cyclability. It is also noticed that the rate capability of Na2Fe0.5Mn0.5P2O7 is better than Na2MnP2O7. Ex situ and CV analyses indicate that Na2Fe0.5Mn0.5P2O7 undergoes a single phase reaction rather than a biphasic reaction due to different Na coordination environment and different Na site occupancy when compared to other pyrophosphate materials (Na2FeP2O7 and Na2MnP2O7). Thermogravimetric analysis (25-550 °C) confirms good thermal stability of Na2Fe0.5Mn0.5P2O7 with only 2% weight loss. Owing to promising electrochemical properties and decent thermal stability, Na2Fe0.5Mn0.5P2O7, can be an attractive cathode for SIBs. PMID

  19. 47 CFR 0.5 - General description of Commission organization and operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false General description of Commission organization and operations. 0.5 Section 0.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMISSION ORGANIZATION Organization General § 0.5 General description of Commission organization and operations. (a) Principal staff units. The Commission...

  20. 30 CFR 57.22233 - Actions at 0.5 percent methane (I-C mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Actions at 0.5 percent methane (I-C mines). 57... MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22233 Actions at 0.5 percent methane (I-C mines). If methane reaches 0.5 percent in the mine atmosphere, ventilation...

  1. 17 CFR 270.0-5 - Procedure with respect to applications and other matters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Procedure with respect to applications and other matters. 270.0-5 Section 270.0-5 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.0-5...

  2. Effects of capping on GaN quantum dots deposited on Al{sub 0.5}Ga{sub 0.5}N by molecular beam epitaxy

    SciTech Connect

    Korytov, M.; Benaissa, M.; Huault, T.; Neisius, T.

    2009-04-06

    The impact of the capping process on the structural and morphological properties of GaN quantum dots (QDs) grown on fully relaxed Al{sub 0.5}Ga{sub 0.5}N templates was studied by transmission electron microscopy. A morphological transition between the surface QDs, which have a pyramidal shape, and the buried ones, which have a truncated pyramid shape, is evidenced. This shape evolution is accompanied by a volume change: buried QDs are bigger than surface ones. Furthermore a phase separation into Al{sub 0.5}Ga{sub 0.5}N barriers was observed in the close vicinity of buried QDs. As a result, the buried QDs were found to be connected with the nearest neighbors by thin Ga-rich zones, whereas Al-rich zones are situated above the QDs.

  3. Thermoelectric properties of PbSe0.5Te0.5: x (PbI2) with endotaxial nanostructures: a promising n-type thermoelectric material

    NASA Astrophysics Data System (ADS)

    Rawat, P. K.; Paul, B.; Banerji, P.

    2013-05-01

    In the present investigation, we report on the thermoelectric properties of PbSe0.5Te0.5: x (PbI2) from room temperature to 625 K. High-resolution transmission electron micrographs of the samples reveal endotaxial nanostructures embedded in a PbSe0.5Te0.5 matrix. The combined effect of mass fluctuation and nanostructures reduces the thermal conductivity to a great extent compared to PbTe and PbSe, without affecting the carrier mobility. As a result, a thermoelectric figure of merit with a value of 1.5 is achieved at 625 K. This value is significantly higher than that of the available state-of-the-art n-type materials.

  4. Static and dynamic magnetic characteristics of BaCo 0.5Mn 0.5Ti 1.0Fe 10O 19

    NASA Astrophysics Data System (ADS)

    Choopani, Saeed; Keyhan, Neda; Ghasemi, Ali; Sharbathi, Ali; Maghsoudi, Iman; Eghbali, Mohammad

    2009-07-01

    The effect of Mn 2+Co 2+Ti 4+ substitution on microwave absorption has been studied for BaCo 0.5Mn 0.5Ti 1.0Fe 10O 19 ferrite-acrylic resin composites in frequency range from 12 to 20 GHz. X-ray diffraction (XRD), scanning electron microscope (SEM), vibrating sample magnetometer, AC susceptometer and vector network analyzer were used to analyze the structural, magnetic and microwave absorption properties. The results showed that the magnetoplumbite structures for all samples have been formed. Based on microwave measurement on reflectivity, BaCo 0.5Mn 0.5Ti 1.0Fe 10O 19 may be a good candidate for electromagnetic compatibility and other practical applications at high frequency.

  5. Electric field-induced tuning of magnetism in PbFe{sub 0.5}Nb{sub 0.5}O{sub 3} at room temperature

    SciTech Connect

    Rayaprol, S. E-mail: brangadi@gmail.com; Mukherjee, S.; Kaushik, S. D.; Matteppanavar, S.; Angadi, B. E-mail: brangadi@gmail.com

    2015-08-07

    We study the influence of electrical poling, carried out at room temperature, on the structure and magnetism of Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} by analyzing the differences observed in structural and magnetic properties before and after the electrical poling. The changes observed in magnetization of Pb(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} before and after electrical poling exhibit considerably strong converse magnetoelectric effect at room temperature. In addition, the strengthening of Fe/Nb-O bond due to electrical poling is discussed on the basis of Raman spectral studies and analysis of neutron diffraction patterns. The potential tunability of magnetization with electrical poling can be an ideal tool for realization of application potential of this multiferroic material.

  6. Ultrahigh strain response with fatigue-free behavior in (Bi0.5Na0.5)TiO3-based lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Hao, Jigong; Xu, Zhijun; Chu, Ruiqing; Li, Wei; Du, Juan; Li, Guorong

    2015-12-01

    In this letter, we report a lead-free piezoelectric ceramic system (Bi0.5Na0.5)1-x Ba x Ti0.98 (Fe0.5Sb0.5)0.02O3 which shows a surprisingly high field-induced nonlinear strain of 0.57% comparable to those obtained in Pb-based antiferroelectrics. The ultrahigh strain response of the composition stems from the composition proximity to the ferroelectric-nonpolar phase boundary, which leads to reversible transformation between a nonpolar phase and a polar ferroelectric phase under cyclic fields. In particular, this material is very attractive for its exceptionally good fatigue resistance (up to 106 cycles) and high temperature stability (25-100 °C) due to its stable nonpolar phase and lower defect density. These findings render the current material a great opportunity for novel applications in ultra-large stroke and nonlinear actuators demanding improved cycling and thermal reliabilities.

  7. Epitaxial growth of AlN and Al0.5Ga0.5N layers on aluminum nitride substrates

    NASA Astrophysics Data System (ADS)

    Schowalter, L. J.; Shusterman, Y.; Wang, R.; Bhat, I.; Arunmozhi, G.; Slack, G. A.

    2000-02-01

    High quality epitaxial AlN and AlxGa1-xN layers have been grown by organo-metallic vapor-phase epitaxy on single crystal a-face AlN substrates. Here we report the characterization of these layers using Rutherford backscattering/ion channeling spectroscopy, atomic force microscopy, double crystal x-ray diffraction, and preliminary electrical results. Ion channeling along the [112¯0] axis gave a minimum yield of 1.5% for an AlN layer and 2.2% for an Al0.5Ga0.5N, indicating excellent crystal quality. A resistivity of 20 Ω cm and a mobility of 20 cm2/V s was measured in a Si-doped, 1-μm-thick Al0.5Ga0.5N grown epitaxially on the AlN substrates.

  8. Epitaxial growth of AlN and Al 0.5Ga 0.5N layers on aluminum nitride substrates

    NASA Astrophysics Data System (ADS)

    Schowalter, L. J.; Rojo, J. C.; Slack, G. A.; Shusterman, Y.; Wang, R.; Bhat, I.; Arunmozhi, G.

    2000-04-01

    High-quality epitaxial AlN and Al xGa 1- xN layers have been grown by organo-metallic vapor-phase epitaxy (OMVPE) on single-crystal AlN substrates. Here we report the characterization of these layers on a-face substrates using Rutherford backscattering/ion channeling spectroscopy (RBS), atomic force microscopy (AFM), double-crystal X-ray diffraction (XRD), and preliminary electrical results. Ion channeling along the [ 1 1 2¯ 0 ] axis gave a minimum yield of 1.5% for an AlN layer and 2.2% for an Al 0.5Ga 0.5N, indicating excellent crystal quality. A resistivity of 20 Ω cm and a mobility of 20 cm 2/V s was measured in a Si-doped, 1 μm-thick, epitaxial Al 0.5Ga 0.5N grown epitaxially on the AlN substrates.

  9. Growth of layered LiNi0.5Mn0.5O2 thin films by pulsed laser deposition for application in microbatteries

    NASA Astrophysics Data System (ADS)

    Xia, Hui; Lu, Li; Meng, Ying Shirley

    2008-01-01

    LiNi0.5Mn0.5O2 films were prepared by pulsed laser deposition on stainless steel (SS) and Au substrates. The substrate was found to play an important role in determining the growth of films. Although similar x-ray diffraction spectra were observed for both types of substrates, Raman spectra exhibited different features. The charge-discharge behavior of the film on the SS substrate indicates a spinel structure while the charge-discharge behavior of the film on the Au substrate indicates a layered structure. The secondary ion mass spectrometry depth-profiling results indicate interdiffusion between the film and the substrate, which inhibits the formation of pure layered LiNi0.5Mn0.5O2 phase.

  10. High electrostrictive strain induced by defect dipoles in acceptor-doped (K0.5Na0.5)NbO3 ceramics

    NASA Astrophysics Data System (ADS)

    Dai, Ye-Jing; Zhao, Yong-Jie; Zhao, Zhe; Zhao, Zhi-Hao; Zhou, Qi-Wu; Zhang, Xiao-Wen

    2016-07-01

    Acceptor doping is an efficient method to improve ferroelectric material performance through the formation of defect dipoles. Here, a high electrostrictive strain of 0.16–0.19%, and large d33\\ast of  >300 pm V‑1 are obtained in CuO-doped (K0.5Na0.5)NbO3 ceramics. We analyzed the orientation relationship and the interaction between defect dipole polarization (P d) along <0 0 1> orientation and spontaneous polarization (P s) parallel to <1 1 0> in orthorhombic (K0.5Na0.5)NbO3. Thus, a ‘coupling effect’ mechanism was suggested to explain how the P d and P s can work together to contribute to the electrostrictive strains in this lead-free piezoelectric ceramic.

  11. Global and local structural variations near the antiferroelectric regime in Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}

    SciTech Connect

    Thangavelu, Karthik; Rayaprol, S.; Siruguri, V.; Sastry, P. U.; Asthana, Saket

    2015-06-24

    Rietveld refinement of neutron and x-ray diffraction data of Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} shows R3c phase stabilization at room temperature. The intermediate antiferroelectric region between 180°C to 280°C exhibits phase coexistence i.e R3c + Pnma, along with decrease in octahedral tilt angle and increase in unit cell volume. The local structural changes observed from Raman scattering in the A-O, Ti-O and TiO{sub 6} phonon modes favor the global structural variation. A possible antiparallel cation displacement due to Pnma phase formation leads to the origin of antiferroelectric ordering in Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}.

  12. Optimization of exchange bias in Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} Heusler alloy layers

    SciTech Connect

    Hirohata, Atsufumi; Izumida, Keisuke; Ishizawa, Satoshi; Nakayama, Tadachika; Sagar, James

    2014-05-07

    We have fabricated and investigated IrMn{sub 3}/Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} stacks to meet the criteria for future spintronic device applications which requires low-temperature crystallisation (<250 °C) and a large exchange bias H{sub ex} (>500 Oe). Such a system would form the pinned layer in spin-valve or tunnel junction applications. We have demonstrated that annealing at 300 °C which can achieve crystalline ordering in the Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} layer giving ∼80% of the predicted saturation magnetisation. We have also induced an exchange bias of ∼240 Oe at the interface. These values are close to the above criteria and confirm the potential of using antiferromagnet/Heusler-alloy stacks in current Si-based processes.

  13. Crystal structure of the ordered perovskite: BaBi{sub 0.5}Sb{sub 0.5}O{sub 3}

    SciTech Connect

    Fu, W.T.; Graaff, R.A.G. de; Gelder, R. de

    1997-06-01

    The structure of BaBi{sub 0.5}Sb{sub 0.5}O{sub 3} is determined by single crystal X-ray diffraction. It is an ordered perovskite, having rhombohedral symmetry, space group R {bar 3}m (No. 166), with lattice parameters a = 6.043(1) {angstrom} and {alpha} = 60.05(2)(degree). The final agreement factor R based on F{sup 2} for 6420 reflections was 0.052. An important structural feature of BaBi{sub 0.5}Sb{sub 0.5}O{sub 3} is the displacements of oxygen atoms from their ideal positions within the pseudo-cubic [110]{sub p} planes, creating an alternative arrangement of (larger) BiO{sub 6} and (smaller) SbO{sub 6} octahedra. Therefore, the valence states of bismuth and antimony can be readily assigned as Bi(III) and Sb(V).

  14. Ferrimagnetic and spin-glass transition in the Aurivillius compound SrBi5Ti4Cr0.5Co0.5O18

    NASA Astrophysics Data System (ADS)

    Yuan, B.; Yang, J.; Zuo, X. Z.; Song, D. P.; Tang, X. W.; Zhu, X. B.; Dai, J. M.; Song, W. H.; Sun, Y. P.

    2015-06-01

    Single-phase polycrystalline SrBi5Ti4CrO18 and SrBi5Ti4Cr0.5Co0.5O18 were synthesized by a modified Pechini method. Both samples have an orthorhombic structure with the space group B2cb. The valence state of Cr is suggested to be +3 and the Co ions exist in the form of Co2+ and Co3+ based on the results of x-ray photoelectron spectroscopy. The sample SrBi5Ti4CrO18 exhibits the paramagnetic state, whereas SrBi5Ti4Cr0.5Co0.5O18 undergoes a ferrimagnetic transition at 89 K originating from the antiferromagnetic coupling of Cr-based and Co-based sublattices. In addition, SrBi5Ti4Cr0.5Co0.5O18 shows a typical spin-glass behavior below 89 K with zν = 6.02 and τ0 = (1.75 ± 0.33) × 10-14 s as evidenced by the results of the frequency dependence of ac susceptibility and magnetic relaxation measurements. In particular, both the dielectric constant and dielectric loss of SrBi5Ti4Cr0.5Co0.5O18 exhibit the characteristics of dielectric relaxation around 89 K with the activation energy of (0.14 ± 0.02) eV, which can be ascribed to the electron hopping of Co2+-VO-Co3+ through the bridging oxygen vacancies.

  15. Co-doping of (Bi0.5Na0.5)TiO3: secondary phase formation and lattice site preference of Co

    NASA Astrophysics Data System (ADS)

    Schmitt, V.; Staab, T. E. M.

    2012-11-01

    Bismuth sodium titanate (Bi0.5Na0.5)TiO3 (BNT) is considered to be one of the most promising lead-free alternatives to piezoelectric lead zirconate titanate (PZT). However, the effect of dopants on the material has so far received little attention from an atomic point of view. In this study we investigated the effects of cobalt-doping on the formation of additional phases and determined the preferred lattice site of cobalt in BNT. The latter was achieved by comparing the measured x-ray absorption near-edge structure (XANES) spectra to numerically calculated spectra of cobalt on various lattice sites in BNT. (Bi0.5Na0.5)TiO3 + x mol% Co (x = 0.0, 0.5, 1.0, 2.6) was synthesized via solid state reaction. As revealed by SEM backscattering images, a secondary phase formed in all doped specimens. Using both XRD and SEM-EDX, it was identified as Co2TiO4 for dopant levels >0.5 mol%. In addition, a certain amount of cobalt was incorporated into BNT, as shown by electron probe microanalysis. This amount increased with increasing dopant levels, suggesting that an equilibrium forms together with the secondary phase. The XANES experiments revealed that cobalt occupies the octahedral B-site in the BNT perovskite lattice, substituting Ti and promoting the formation of oxygen vacancies in the material.

  16. Ordered structure and thermal expansion in tungsten bronze Pb₂K(0.5)Li(0.5)Nb₅O₁₅.

    PubMed

    Lin, Kun; Rong, Yangchun; Wu, Hui; Huang, Qingzhen; You, Li; Ren, Yang; Fan, Longlong; Chen, Jun; Xing, Xianran

    2014-09-01

    The crystal structure and thermal expansion behaviors of a new tetragonal tungsten bronze (TTB) ferroelectric, Pb2K(0.5)Li(0.5)Nb5O15, were systematically investigated by selected-area electron diffraction (SAED), neutron powder diffraction, synchrotron X-ray diffraction (XRD), and high-temperature XRD. SAED and Rietveld refinement reveal that Pb2K(0.5)Li(0.5)Nb5O15 displays a commensurate superstructure of simple orthorhombic TTB structure at room temperature. The structure can be described with space group Bb2₁m. The transition to a paraelectric phase (P4/mbm) occurs at 500 °C. Compared with Pb2KNb5O15 (PKN), the substitution of 0.5K(+) with small 0.5Li(+) into PKN causes the tilting of NbO6 octahedra away from the c axis with Δθ ≈ 10° and raises the Curie temperature by 40 °C, and the negative thermal expansion coefficient along the polar b axis increases more than 50% in the temperature range 25-500 °C. We present that, by introduction of Li(+), the enhanced spontaneous polarization is responsible for the enhanced negative thermal expansion along the b axis, which may be caused by more Pb(2+) in the pentagonal caves. PMID:25116333

  17. Nuclear magnetic resonance study of thin Co2FeAl0.5Si0.5 Heusler films with varying thickness

    NASA Astrophysics Data System (ADS)

    Alfonsov, A.; Peters, B.; Yang, F. Y.; Büchner, B.; Wurmehl, S.

    2015-02-01

    Type, degree, and evolution of structural order are important aspects for understanding and controlling the properties of highly spin-polarized Heusler compounds, in particular, with respect to the optimal film growth procedure. In this work, we compare the structural order and the local magnetic properties revealed by nuclear magnetic resonance (NMR) spectroscopy with the macroscopic properties of thin Co2FeAl 0.5Si 0.5 Heusler films with varying thickness. A detailed analysis of the measured NMR spectra presented in this paper enables us to find a very high degree of L 21 -type ordering up to 81% concomitantly with excess Fe of 8%-13% at the expense of Al and Si. We show that the formation of certain types of order depends not only on the thermodynamic phase diagrams as in bulk samples, but also that the kinetic control may contribute to the phase formation in thin films. It is an exciting finding that Co2FeAl 0.5Si 0.5 can form an almost ideal L 21 structure in films, though with a considerable amount of Fe-Al/Si off stoichiometry. Moreover, the very good quality of the films as demonstrated by our NMR study suggests that the technique of off-axis sputtering used to grow the films sets the stage for the optimized performance of Co2FeAl 0.5Si 0.5 in spintronic devices.

  18. Valence states and metamagnetic phase transition in partially B -site-disordered perovskite EuMn0.5Co0.5O3

    NASA Astrophysics Data System (ADS)

    Vasiliev, A. N.; Volkova, O. S.; Lobanovskii, L. S.; Troyanchuk, I. O.; Hu, Z.; Tjeng, L. H.; Khomskii, D. I.; Lin, H.-J.; Chen, C. T.; Tristan, N.; Kretzschmar, F.; Klingeler, R.; Büchner, B.

    2008-03-01

    The valence states of transition metals were studied by measuring the x-ray absorption spectra at both MnL2,3 and CoL2,3 edges of partially B -site-disordered perovskite EuMn0.5Co0.5O3 . By comparison with analogous spectra in various Co- and Mn-based compounds, the divalent state of the Co ions and the tetravalent state of the Mn ions were established analogous to Mn4+/Co2+ charge ordering found by Dass and Goodenough [Phys. Rev. B 67, 014401 (2003)] in LaMn0.5Co0.5O3 . The specific heat and magnetic susceptibility data indicate the formation of the magnetically ordered state at TC˜120K . The first-order metamagnetic transitions seen in EuMn0.5Co0.5O3 at T

  19. Effect of Pr Addition on Properties of Sn-0.5Ag-0.7Cu-0.5Ga Lead-Free Solder

    NASA Astrophysics Data System (ADS)

    Xujing, Nan; Songbai, Xue; Peizhuo, Zhai; Dongxue, Luo

    2016-07-01

    In this paper, the effect of Pr addition on the microstructure and properties of Sn-0.5Ag-0.7Cu-0.5Ga lead-free solder was investigated. It was found that the properties of Sn-0.5Ag-0.7Cu-0.5Ga-xPr solder, such as wettability and mechanical properties, could be obviously improved, and the optimal content of Pr was about 0.06 wt.%. The microstructure of Sn-0.5Ag-0.7Cu-0.5Ga-0.06Pr solder showed that the β-Sn matrix and intermetallic compound (IMC) grains were significantly refined, and refinement and homogenization of the microstructure achieved maximum efficiency, which played the role of fine grain strengthening and second phase strengthening. However, as the content of Pr exceeded 0.06 wt.%, some uneven distributed black phases of PrSn3 were found in the β-Sn matrix, which seriously worsened the microstructure and properties of the solders. As a surface-active element, the segregation of Pr at the molten solder interface could give rise to decreasing the interface tension. Consequently, adding a suitable amount of Pr could play a positive role in improving the properties of the solders.

  20. Fabrication and evaluation of a single-element Bi0.5Na0.5TiO3-based ultrasonic transducer.

    PubMed

    Hejazi, M Mehdi; Jadidian, Bahram; Safari, Ahmad

    2012-08-01

    This paper discusses the fabrication and characterization of a single-element ultrasonic transducer with a lead-free piezoelectric active element. A piezoelectric ceramic with composition of 0.88Bi(0.5)Na(0.5)TiO(3)-0.08Bi(0.5)K(0.5)TiO(3)- 0.04Bi(0.5)Li(0.5)TiO(3) was chosen as the active element of the transducer. This composition exhibited a thickness coupling coefficient (kt) of 0.45, a dielectric constant of 440 (at 1 kHz), and a longitudinal piezoelectric coefficient (d(33)) of 84 pC·N(-1). To make the transducer, the ceramic was sandwiched between an epoxy-tungsten backing layer and a silver epoxy matching layer. An epoxy lens was also incorporated into the transducer's design to focus the ultrasound beam. The focused transducer with a center frequency of about 23 MHz demonstrated a -6-dB bandwidth of 55% and an insertion loss of -32 dB; the -20-dB pulsed length was measured to be 150 ns. A phantom made of copper wires (30 μm in diameter) was utilized to investigate the imaging capability of the transducer. The results indicated that the fabricated transducer, with a lateral resolution of 260 μm and a relatively high depolarization temperature, could be considered as a candidate for replacement of lead-based ultrasonic transducers. PMID:22899131

  1. Electronic structure of a new layered bismuth oxyselenide superconductor: LaO0.5F0.5BiSe2.

    PubMed

    Xia, M; Jiang, J; Niu, X H; Liu, J Z; Wen, C H P; Lu, H Y; Lou, X; Pu, Y J; Huang, Z C; Zhu, Xiyu; Wen, H H; Xie, B P; Shen, D W; Feng, D L

    2015-07-22

    LaO(0.5)F(0.5)BiSe(2) is a new layered superconductor discovered recently, which shows the superconducting transition temperature of 3.5 K. With angle-resolved photoemission spectroscopy, we study the electronic structure of LaO(0.5)F(0.5)BiSe(2) comprehensively. Two electron-like bands are located around the X point of the Brillouin zone, and the outer pockets connect with each other and form large Fermi surface around Γ and M. These bands show negligible k(z) dispersion, indicating their two-dimensional nature. Based on the Luttinger theorem, the carrier concentration is about 0.53 e(-) per unit cell, close to its nominal value. Moreover, the photoemission data and the band structure calculations agree very well, and the renormalization factor is nearly 1.0, indicating the electron correlations in this material are rather weak. Our results suggest that LaO(0.5)F(0.5)BiSe(2) is a conventional BCS superconductor without strong electron correlations. PMID:26102451

  2. The hierarchical structure of cubic K0.5La0.5TiO3 layers and enhanced photocatalytic hydrogen evolution after surface acidification.

    PubMed

    Zhao, Wenli; Zhu, Guilian; Zhao, Wei; Lin, Tianquan; Xu, Fangfang; Huang, Fuqiang

    2015-11-14

    Transition-metal perovskite oxides possess rich functionalities in the fields of ferroelectrics, piezoelectrics, superconductors, dielectrics, fuel cells and photocatalysis. Nano-facet control of the cubic ATiO3 (A: a divalent cation) phase, a typical perovskite oxide, may result in new properties or phenomena not observable in the bulk material. Herein, we first report a puzzle-like 3D hierarchical structure constructed with K0.5La0.5TiO3 nanosheets. Surprisingly, K0.5La0.5TiO3 has a cubic symmetry similar to a SrTiO3 perovskite. The unusual phase is synthesized by a simple one-pot hydrothermal strategy without using any structure-directing agent. After modest acidification, the assembled 3D hierarchical structure is etched into a core-shell nanostructure which consists of a crystalline K0.5La0.5TiO3 core and an amorphous TiO2 shell. The acid-treated sample exhibits remarkably enhanced photocatalytic H2 production, which is over 60 times higher than the pristine sample. PMID:26455735

  3. Use of the "Mental Health Inventory - 5" with Portuguese 10-15 years old.

    PubMed

    Marques, Susana C; Pais-Ribeiro, José Luis; Lopez, Shane J

    2011-05-01

    The present study describes the psychometric properties of the Portuguese version of the Mental Health Inventory-5 for use with young adolescents. A sample of 367 Portuguese students (aged 10-15 years) completed the Portuguese-language versions of Mental Health Inventory-5 (MHI-5; Berwick et al., 1991), Children's Hope Scale (CHS; Snyder et al., 1997), Students' Life Satisfaction Scale (SLSS; Huebner, 1991a), and Global Self-Worth Sub-scale (Harter, 1985). Analysis of readability, reliability (internal consistency and 1-year stability), factor structure, and criterion-related validity suggested that the MHI-5 can be appropriately used in this age group. Implications of the findings are discussed. PMID:21568203

  4. Energy dependence of cosmic ray composition above 10(15) GeV/nucleus

    NASA Technical Reports Server (NTRS)

    Linsley, J.; Fichtel, C. E.

    1985-01-01

    It is argued that above 10 to the 5th power GeV/nucleus, in the range where charge-resolved spectra have not yet been determined, the appropriate measures of equal-energy composition are 1nA and 1nA , the mean value and dispersion relative to the mean value and dispersion relative to the mean of 1nA, where A is the mass number. Experimental data which are sensitive to changes in 1nA with increasing energy are examined. It is found that, taken as a whole, they show no change (+ or 0.5) between 10 to the 5th power and 10 to the 6th power GeV, and a decrease of 1.5 + or - 0.5 between 10 to the 6th power and 10 to the 8th power GeV, with no further change + or - 0.5) above 10 to the 8th power GeV. Taken as a whole, the various indirect estimates of the absolute value of 1nA above 10 to the 5th power GeV/nucleus are also consistent with this pattern. For a wide range of astrophysically plausible composition models the value of the other measure, 1nA is insensitive to changes in 1nA . Because of this the existing data on 1nA can likewise easily be reconciled with this pattern.

  5. Synthesis crystal structure and ionic conductivity of Ca 0.5Bi 3V 2O 10 and Sr 0.5Bi 3V 2O 10

    NASA Astrophysics Data System (ADS)

    Porob, Digamber G.; Guru Row, T. N.

    2004-12-01

    Two new compounds Ca 0.5Bi 3V 2O 10 and Sr 0.5Bi 3V 2O 10 have been synthesized in the ternary system: MO-Bi 2O 3-V 2O 5 system ( M=M 2+). The crystal structure of Sr 0.5Bi 3V 2O 10 has been determined from single crystal X-ray diffraction data, space group P1¯ and Z=2, with cell parameters a=7.1453(3) Å, b=7.8921(3) Å, c=9.3297(3) Å, α=106.444(2)°, β=94.088(2)°, γ=112.445(2)°, V=456.72(4) Å 3. Ca 0.5Bi 3V 2O 10 is isostructural with Sr 0.5Bi 3V 2O 10, with, a=7.0810(2) Å, b=7.8447(2) Å, c=9.3607(2) Å, α=106.202(1)°, β=94.572(1)°, γ=112.659(1)°, V=450.38(2) Å 3 and its structure has been refined by Rietveld method using powder X-ray data. The crystal structure consists of infinite chains of (Bi 2O 2) along c-axis formed by linkage of BiO 8 and BiO 6 polyhedra interconnected by MO 8 polyhedra forming 2D layers in ac plane. The vanadate tetrahedra are sandwiched between these layers. Conductivity measurements give a maximum conductivity value of 4.54×10 -5 and 3.63×10 -5 S cm -1 for Ca 0.5Bi 3V 2O 10 and Sr 0.5Bi 3V 2O 10, respectively at 725 °C.

  6. Structure and Magnetic Order in the Series BixRE1-xFe0.5Mn0.5O3 (RE = La, Nd)

    SciTech Connect

    Bridges, Craig A; Safa-Sefat, Athena; Payzant, E Andrew; Cranswick, Lachlan; Paranthaman, Mariappan Parans

    2011-01-01

    The influence of Bi3+ on the structure and magnetic properties of the rare-earth containing perovskites REFe0.5Mn0.5O3 (RE= La,Nd) was studied, and the limit of bismuth substitution was determined to be x 0.5 in BixRE1-xFe0.5Mn0.5O3+ (RE= La,Nd) at ambient pressure. Both X-ray and Neutron powder diffraction data were used to determine the crystal structures. Crystal structures in both La and Nd series were determined to be GdFeO3-type Pnma with the exception of the Bi0.3La0.7Fe0.5Mn0.5O3+ sample, which is monoclinic I2/a in the a-b-b- tilt scheme. Bond valence results suggest that the oxidation states are most consistent with Fe3+ and Mn3+, with some oxidation to form Mn4+ suggested by Rietveld refinement of oxygen excess and bismuth deficiency from neutron powder diffraction data. The samples undergo a transition to G-type antiferromagnetic order along with a weak ferromagnetic component, mixed with cluster-glass type behavior. Long range ordering temperatures TN in the range of 240-255K were also observed, with a significantly lower ordered magnetic moment in the case of lanthanum (M ~ 1.7-1.9 B) than in the case of neodymium (M ~ 2.1 B). The substitution of bismuth into the lattice results with a drop in T N relative to the lanthanide end-members, but exhibits no clear correlation with the magnitude of the ordered moment on the B-site.

  7. Dielectric relaxation and magnetodielectric response in DyMn{sub 0.5}Cr{sub 0.5}O{sub 3}

    SciTech Connect

    Yuan, B.; Yang, J. Zuo, X. Z.; Zhu, X. B.; Dai, J. M.; Song, W. H.; Kan, X. C.; Zu, L.; Sun, Y. P.

    2015-09-28

    We investigate the structural, magnetic, and magnetodielectric properties of DyMn{sub 0.5}Cr{sub 0.5}O{sub 3}. The sample can be indexed with an orthorhombic phase with B site disordered space group Pbnm. The valence state of both Mn and Cr ions are suggested to be +3 based on the results of x-ray photoelectron spectroscopy. Two thermally excited dielectric relaxation at temperatures T{sub N2} < T< 300 K and large magnetodielectric effect (MDC = 20%–30%) due to the disordered arrangement of Mn{sup 3+}/Cr{sup 3+} ions associated with electron hopping between them are observed. The absence of any noticeable magnetoresistance effect (MR < 0.5%) demonstrates that the observed magnetodielectric effect is an intrinsic behavior. These results suggest that DyMn{sub 0.5}Cr{sub 0.5}O{sub 3} is a magnetodielectric compound, whose dielectric properties are dependence of the applied magnetic field, which exhibits such effects near room temperature and holds great promise for future device applications.

  8. Optical Properties of Ferroelectric Epitaxial K0.5Na0.5NbO3 Films in Visible to Ultraviolet Range.

    PubMed

    Chernova, E; Pacherova, O; Kocourek, T; Jelinek, M; Dejneka, A; Tyunina, M

    2016-01-01

    The complex index of refraction in the spectral range of 0.74 to 4.5 eV is studied by variable-angle spectroscopic ellipsometry in ferroelectric K0.5Na0.5NbO3 films. The 20-nm-thick cube-on-cube-type epitaxial films are grown on SrTiO3(001) and DyScO3(011) single-crystal substrates. The films are transparent and exhibit a significant difference between refractive indices Δn = 0.5 at photon energies below 3 eV. The energies of optical transitions are in the range of 3.15-4.30 eV and differ by 0.2-0.3 eV in these films. The observed behavior is discussed in terms of lattice strain and strain-induced ferroelectric polarization in epitaxial perovskite oxide films. PMID:27074042

  9. Optical Properties of Ferroelectric Epitaxial K0.5Na0.5NbO3 Films in Visible to Ultraviolet Range

    PubMed Central

    Pacherova, O.; Kocourek, T.; Jelinek, M.; Dejneka, A.; Tyunina, M.

    2016-01-01

    The complex index of refraction in the spectral range of 0.74 to 4.5 eV is studied by variable-angle spectroscopic ellipsometry in ferroelectric K0.5Na0.5NbO3 films. The 20-nm-thick cube-on-cube-type epitaxial films are grown on SrTiO3(001) and DyScO3(011) single-crystal substrates. The films are transparent and exhibit a significant difference between refractive indices Δn = 0.5 at photon energies below 3 eV. The energies of optical transitions are in the range of 3.15–4.30 eV and differ by 0.2–0.3 eV in these films. The observed behavior is discussed in terms of lattice strain and strain-induced ferroelectric polarization in epitaxial perovskite oxide films. PMID:27074042

  10. Influences of phase transition and microstructure on dielectric properties of Bi0.5Na0.5Zr1-xTixO3 ceramics

    PubMed Central

    2012-01-01

    Bismuth sodium zirconate titanate ceramics with the formula Bi0.5Na0.5Zr1-xTixO3 [BNZT], where x = 0.3, 0.4, 0.5, and 0.6, were prepared by a conventional solid-state sintering method. Phase identification was investigated using an X-ray diffraction technique. All compositions exhibited complete solubility of Ti4+ at the Zr4+ site. Both a decrease of unit cell size and phase transition from an orthorhombic Zr-rich composition to a rhombohedral crystal structure in a Ti-rich composition were observed as a result of Ti4+ substitution. These changes caused dielectric properties of BNZT ceramics to enhance. Microstructural observation carried out employing SEM showed that average grain size decreased when addition of Ti increased. Grain size difference of BNZT above 0.4 mole fraction of Ti4+ displayed a significant increase of dielectric constant at room temperature. PMID:22221960

  11. Spin reorientation in multiferroic spinel Co0.5Fe0.5Cr2O4 with Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Myoung, Bo Ra; Kim, Chul Sung

    2015-05-01

    We studied the magnetic properties of multiferroic spinel Co0.5Fe0.5Cr2O4, especially focusing on the spin-ordering, spin-reorientation, and charge re-distribution effects. From the Rietveld refinement analysis, the crystal structure was identified to be a normal cubic spinel of Fd-3m. Based on the temperature-dependent measurements of the magnetization and magnetic hyperfine field (Hhf), Curie temperature (TC) of Co0.5Fe0.5Cr2O4 was determined to be around 86 K where Hhf ≅ 0. From the change of slope in the M-T curve, the conical-spiral magnetic ordering temperature was determined to be 20 K, which coincides with Hhf measurement. Also, we have observed the decrease in the slope of the electric quadrupole splitting (ΔEQ) curve above 20 K, suggesting that the change in ΔEQ around TS is originated from charge redistribution due to the spin-relocation associated with the distortion of each tetrahedral site around Fe2+ ion above TS. This indicates that Co0.5Fe0.5Cr2O4 has the noncollinear conical-spiral spin ordering with incommensurate spin structure below TS, while above TS, it has ferrimagnetic spin ordering with commensuration in the collinear state. In addition, the Jahn-teller distortion temperature is measured to be around 155 K, since both ΔEQ and Δ1 of 5T2g band decrease rapidly with increasing temperature and disappear around 155 K.

  12. Significantly enhanced ferroelectricity and magnetic properties in (Sr0.5Ca0.5)TiO3-modified BiFeO3 ceramics

    NASA Astrophysics Data System (ADS)

    Liu, Juan; Liu, Xiao Qiang; Chen, Xiang Ming

    2015-05-01

    BiFeO3 multiferroic ceramics were modified by introducing (Sr0.5Ca0.5)TiO3 to form solid solutions. The single phase structure was easy to be obtained in Bi1-x(Sr0.5Ca0.5)xFe1-xTixO3 (x = 0.2, 0.25, 0.3, and 0.4) solid solutions. Rietveld refinement of X-ray diffraction data revealed a transition from rhombohedral R3c (x = 0.2, 0.25, and 0.3) to orthorhombic Pnma (x = 0.4). Current density-field (J-E) characteristics indicated that the leakage current density was reduced by three orders of magnitude in Bi1-x(Sr0.5Ca0.5)xFe1-xTixO3 ceramics. Both the ferroelectricity and magnetic properties were significantly enhanced in the present solid solutions. P-E hysteresis loop measurements with dynamic leakage current compensation methods showed the significantly enhanced ferroelectric properties for x = 0.25 and 0.3 and the paraelectric behavior for x = 0.4. The best ferromagnetic characteristics were achieved in the composition of x = 0.25, where the saturated M-H loop was determined with Mr = 34.8 emu/mol. The improvement of ferroelectricity was mainly due to the suppressed leakage current, and the enhanced magnetism originated from the partial substitution of Fe3+ by Ti4+, which destroyed its previous spiral structure to allow the appearance of a macroscopic magnetization.

  13. Synthesis of manganite perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles in w/o-microemulsion

    SciTech Connect

    Lopez-Trosell, Alejandra . E-mail: Lopez.Alejandra@chem.tu-berlin.de; Schomaecker, Reinhard . E-mail: schomaecker@tu-berlin.de

    2006-02-02

    In this paper, w/o-microemulsions were employed to produce nanoparticles of the perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3}, which have a size of approximately 20-50 nm. The procedure was carried out using sodium hydroxide or ammonia as co-precipitation agent. The precursor was transformed to perovskite by calcinations at 580 deg. C. Nanosized particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N{sub 2} adsorption (BET)

  14. Chemical potential fluctuations in topological insulator (Bi0.5Sb0.5)2Te3-films visualized by photocurrent spectroscopy

    NASA Astrophysics Data System (ADS)

    Kastl, Christoph; Seifert, Paul; He, Xiaoyue; Wu, Kehui; Li, Yongqing; Holleitner, Alexander

    2015-06-01

    We investigate the photocurrent properties of the topological insulator (Bi0.5Sb0.5)2Te3 on SrTiO3-substrates. We find reproducible, submicron photocurrent patterns generated by long-range chemical potential fluctuations, occurring predominantly at the topological insulator/substrate interface. We fabricate nano-plowed constrictions which comprise single potential fluctuations. Hereby, we can quantify the magnitude of the disorder potential to be in the meV range. The results further suggest a dominating photo-thermoelectric current generated in the surface states in such nanoscale constrictions.

  15. Direct band-gap measurement on epitaxial Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} Heusler-alloy films

    SciTech Connect

    Alhuwaymel, Tariq F.; Carpenter, Robert; Yu, Chris Nga Tung; Kuerbanjiang, Balati; Lazarov, Vlado K.; Abdullah, Ranjdar M.; El-Gomati, Mohamed; Hirohata, Atsufumi

    2015-05-07

    In this study, a newly developed band-gap measurement technique has been used to characterise epitaxial Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} (CFAS) films. The CFAS films were deposited on MgO(001) substrate by ultra high vacuum molecular beam epitaxy. The band-gap for the as deposited films was found to be ∼110 meV when measured at room temperature. This simple technique provides a macroscopic analysis of the half-metallic properties of a thin film. This allows for simple optimisation of growth and annealing conditions.

  16. Strain control of superlattice implies weak charge-lattice coupling in La{sub 0.5}Ca{sub 0.5}MnO{sub 3}

    SciTech Connect

    Cox, S.; Chapman, J. C.; Midgley, P. A.; Mathur, N. D.; Rosten, E.; Kos, S.; Littlewood, P. B.; Calderon, M. J.; Kang, D.-J.

    2006-04-01

    We have recently argued that manganites do not possess stripes of charge order, implying that the electron-lattice coupling is weak [Loudon et al., Phys. Rev. Lett. 94, 097202 (2005)]. Here we independently argue the same conclusion based on transmission electron microscopy measurements of a nanopatterned epitaxial film of La{sub 0.5}Ca{sub 0.5}MnO{sub 3}. In strain relaxed regions, the superlattice period is modified by 2% to 3% with respect to the parent lattice, suggesting that the two are not strongly tied.

  17. Collective dipole behavior and unusual morphotropic phase boundary in ferroelectric Pb(Zr(0.5)Ti(0.5))O3 nanowires.

    PubMed

    Fu, Xiujun; Naumov, Ivan I; Fu, Huaxiang

    2013-02-13

    Dipole collective behavior and phase transition in ferroelectric (FE) Pb(Zr(0.5)Ti(0.5))O(3) nanowires, caused by modulated electric fields, are reported. Our result also leads to the finding of a rather outstanding electromechanical d(31) response in a 8.4 nm diameter PZT wire, which may potentially outperform bulk PMN-PT and PZN-PT. Moreover, we further demonstrate the existence of a new type of morphotropic phase boundary (MPB) that bridges two dissimilar structure phases of different order parameters. Microscopic insights for understanding the collective behavior and the structural phase within the new MPB are provided. PMID:23256599

  18. Fabrication of highly spin-polarized Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} thin-films

    SciTech Connect

    Vahidi, M.; Zhang, S. K.; Yu, L.; Huang, M.; Newman, N.; Gifford, J. A.; Chen, T. Y.; Krishnamurthy, S.; Yu, Z. G.; Youngbull, C.

    2014-04-01

    Ferromagnetic Heusler Co{sub 2}FeAl{sub 0.5}Si{sub 0.5} epitaxial thin-films have been fabricated in the L2{sub 1} structure with saturation magnetizations over 1200 emu/cm{sup 3}. Andreev reflection measurements show that the spin polarization is as high as 80% in samples sputtered on unheated MgO (100) substrates and annealed at high temperatures. However, the spin polarization is considerably smaller in samples deposited on heated substrates.

  19. Quantitative study of atomic ordering in Ga0.5In0.5P thin films by 31P nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Tycko, Robert; Dabbagh, Gary; Kurtz, Sarah R.; Goral, John P.

    1992-06-01

    We use 31P nuclear-magnetic-resonance (NMR) spectra to measure the degree of cation ordering in thin films of the semiconductor alloy Ga0.5In0.5P grown by organometallic vapor-phase epitaxy. We show that the five possible GanIn4-nP clusters in GaxIn1-xP give rise to resolved NMR lines under magic-angle spinning, allowing a determination of the degree of cation ordering from the relative areas of the five lines. The ordering is shown to be weak (order parameter <=0.6) even in films that appear highly ordered in transmission electron microscopy.

  20. Core structure of EAS in 10(15) to 10(17) eV

    NASA Technical Reports Server (NTRS)

    Hara, T.; Hatano, Y.; Hayashida, N.; Kifune, T.; Nagano, M.; Tanahashi, G.

    1985-01-01

    With the use of Akeno calorimeter, the attenuation of particles in concrete is analyzed as the function of the shower size of 10 to the 5th power to 10 to the 7th power. The attenuation length does not depend much on the shower size but depends a little on the shower age. The average value is approx. 150 g/sq cm for s = 0.5 to 0.85 and approx. 40 g/sq cm for s = 0.85 to 1.15. These values and their fluctuations are consistent with the equi-intensity curves of extensive air showers (EAS).

  1. Electrical Characterization Induced by Structural Modulation in (Ca0.28Ba0.72)2.5-0.5 x (Na0.5K0.5) x Nb5O15 Ceramics

    NASA Astrophysics Data System (ADS)

    Yang, Bian; Wei, Lingling; Wang, Zhongming; Kang, Shoucheng; Chao, Xiaolian; Yang, Zupei

    2016-01-01

    (Ca0.28Ba0.72)2.5-0.5 x (Na0.5K0.5) x Nb5O15 ceramics (CBNKN, 0.0 ≤ x ≤ 0.4) with `unfilled' tungsten bronze structure were prepared by the conventional solid-state reaction method. Effects of alkalis-introducing concentration in A-sites on the microstructure, dielectric and ferroelectric properties were investigated in detail. Pure tungsten bronze structure could be obtained in all compositions according to the x-ray diffraction patterns. Raman spectroscopy results showed that co-introducing Na+ and K+ in A sites to decrease the structural vacancy could enhance the dielectric and ferroelectric properties, which was attributed to the stronger interaction inside NbO6 octahedron and large distortion degree of NbO6 polar unit. Traditional temperature dependence of dielectric characteristics and well-saturated ferroelectric hysteresis loops were observed for all CBNKN ceramics. The better comprehensive dielectric and ferroelectric properties were obtained at x = 0.2 due to the bigger distortion degree of NbO6 polar unit and the highest densification. Whereas higher alkalis-introducing concentration would deteriorate the physical and electrical properties due to the poor sintering behavior. In addition, the frequency dependence of ɛ around transition temperature ( T c) and the temperature dependence of ferroelectric properties were discussed to further clarify the relationship between composition and performance.

  2. Pressure-induced phase transition in La1–xSmxO0.5F0.5BiS2

    DOE PAGESBeta

    Fang, Y.; Yazici, D.; White, B. D.; Maple, M. B.

    2015-09-15

    Electrical resistivity measurements on La1–xSmxO0.5F0.5BiS2 (x = 0.1, 0.3, 0.6, 0.8) have been performed under applied pressures up to 2.6 GPa from 2 K to room temperature. The superconducting transition temperature Tc of each sample significantly increases at a Sm-concentration dependent pressure Pt, indicating a pressure-induced phase transition from a low-Tc to a high-Tc phase. At ambient pressure, Tc increases dramatically from 2.8 K at x = 0.1 to 5.4 K at x = 0.8; however, the Tc values at P > Pt decrease slightly with x and Pt shifts to higher pressures with Sm substitution. In the normal state,more » semiconducting-like behavior is suppressed and metallic conduction is induced with increasing pressure in all of the samples. Furthermore, these results suggest that the pressure dependence of Tc for the BiS2-based superconductors is related to the lattice parameters at ambient pressure and enable us to estimate the evolution of Tc for SmO0.5F0.5BiS2 under pressure.« less

  3. Twofold spin reorientation and field-induced incomplete phase transition in single-crystal Dy0.5Pr0.5FeO3

    NASA Astrophysics Data System (ADS)

    Wu, Hailong; Cao, Shixun; Liu, Ming; Cao, Yiming; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2014-10-01

    We report an intriguing twofold spin reorientation transition of type Γ4(Gx,Ay,Fz)→Γ1(Ax,Gy,Cz)→Γ2(Fx,Cy,Gz) for the Fe3+ magnetic sublattice near spin reorientation temperatures TSR1˜77 K and TSR2˜45 K in a rare-earth orthoferrite Dy0.5Pr0.5FeO3 single crystal. Magnetic-field-induced incomplete spin-configuration transitions (Γ4→Γ41→Γ42 for H =20kOe and Γ4→Γ42 for H =40kOe) were observed by measurement of magnetization as a function of temperature. The spin reorientation temperature of a Dy0.5Pr0.5FeO3 single crystal can be controlled by changing the magnitude of the applied magnetic field. We also show that spin reorientation of the Γ1→Γ4 type between TSR2 and TSR1 can be induced by an applied magnetic field along the c axis. The origin of the intriguing magnetic behavior is ascribed to the anisotropic effective field whose strength is determined by the interactions with R3+(R =Dy,Pr) spins and can be modified by the external applied magnetic field. It provides deeper insight into the Fe3+-R3+ magnetic interaction which dominates the sophisticated magnetic phase transitions in the rare-earth orthoferrites.

  4. Structural, dielectric and magnetic properties of (Pb1-xCax)(Fe0.5Nb0.5)O3 solid solution ceramics

    NASA Astrophysics Data System (ADS)

    Puri, Maalti; Bahel, Shalini; Raevski, I. P.; Narang, Sukhleen Bindra

    2016-06-01

    Ceramic samples of (Pb1-xCax)(Fe0.5Nb0.5)O3 with x=0.0, 0.20, 0.40, 0.45, 0.50, 0.55, 0.60 and 1.0 were fabricated by columbite precursor method. All the synthesized samples have a perovskite structure and unit cell volume decreases with increasing Ca content. The substitution of Ca for Pb has been found to have a pronounced effect on structural, dielectric and magnetic properties. Saturated magnetic loops were observed at room temperature for compositions with x≥0.40. The observed maximal magnetization at room temperature is rather small and varies non-monotonically with increasing Ca contents. It is supposed that room-temperature magnetic properties of (Pb1-xCax)(Fe0.5Nb0.5)O3 ceramics might be due to the presence of ferromagnetic impurity, presumably PbFe12O19 and/or CaFe12O19.

  5. Evidence of spin glass like ordering and electronic phase arrest in Pr3+ doped Sm0.5Sr0.5MnO3 bulk manganites

    NASA Astrophysics Data System (ADS)

    Giri, S. K.; Panda, J.; Nath, T. K.

    2012-06-01

    The effect of doping of rare earth Pr3+ ion replacing Sm3+ in Sm0.5Sr0.5MnO3 is investigated in details. Measurements of linear and non linear ac magnetic susceptibility, resistivity, magnetoresistance on chemically synthesized (Sm0.5-xPrx)Sr0.5MnO3 shows various interesting features with doping level x=0.15. Here we observe the frequency independent FM-PM transition at higher temperature followed by a frequency dependent re-entered magnetic transition at lower temperature through complex ac susceptibility measurements. We have ascribed our observation to the formation of finite size ferromagnetic clusters which are formed as a consequence of intrinsic phase separation and undergo Spin glass-like freezing below certain temperature in this manganite. The magnetoresistance of the samples also show strong irreversibility with respect to sweeping of the field between highest positive and negative values. All these experimental results have been attributed to phase separation effect and kinetic arrest of electronically phase separated system.

  6. A study on the wake-up effect of ferroelectric Hf0.5Zr0.5O2 films by pulse-switching measurement

    NASA Astrophysics Data System (ADS)

    Kim, Han Joon; Park, Min Hyuk; Kim, Yu Jin; Lee, Young Hwan; Moon, Taehwan; Kim, Keum Do; Hyun, Seung Dam; Hwang, Cheol Seong

    2016-01-01

    The appearance of ferroelectric (FE) and anti-ferroelectric (AFE) properties in HfO2-based thin films is highly intriguing in terms of both the scientific context and practical application in various electronic and energy-related devices. Interestingly, these materials showed a ``wake-up effect'', which refers to the increase in remanent polarization with increasing electric field cycling number before the occurrence of the fatigue effect. In this work, the wake-up effect from Hf0.5Zr0.5O2 was carefully examined by the pulse-switching experiment. In the pristine state, the Hf0.5Zr0.5O2 film mostly showed FE-like behavior with a small contribution from AFE-like distortion, which could be ascribed to the involvement of the AFE phase. The field cycling of only 100 cycles almost completely transformed the AFE phase into the FE phase by depinning the pinned domains. The influence of field cycling on the interfacial layer was also examined through the pulse-switching experiments.

  7. 59Co nuclear magnetic resonance study of the local distribution of atoms in the Heusler compound Co2FeAl0.5Si0.5

    NASA Astrophysics Data System (ADS)

    Wurmehl, Sabine; Kohlhepp, Jürgen T.; Swagten, Henk J. M.; Koopmans, Bert

    2012-02-01

    In this work, the spin-echo nuclear magnetic resonance (NMR) technique is used to probe the local structure of Co2FeAl0.5Si0.5 bulk samples. The 59Co NMR spectrum of the Heusler compound Co2FeAl0.5Si0.5 consists of four main resonance lines with an underlying sub-structure. The splitting into the main resonance lines is explained by contributions of the B2 type structure. The sub-lines are attributed to a random distribution of Al and Si. By comparing the experimental results with an appropriate multinomial distribution, the fraction of the Al/Si intermixing and the ratio between the contributing structure types is assigned. The main structural contribution of as-cast bulk samples is of B2 type with 38% of L21 contributions. The L21 contribution can be enhanced to 59% by an appropriate annealing process. However, B2 contributions are still present after annealing. Additional foreign phases such as fcc-Co and Co-Al, with relative contributions of less than one percent, are also found in both as-cast and annealed samples. Resonance lines related to slight amounts of the ternary, parental Heusler compounds Co2FeAl and Co2FeSi are also observed.

  8. Pressure-induced phase transition in La1 -xSmxO0.5F0.5BiS2

    NASA Astrophysics Data System (ADS)

    Fang, Y.; Yazici, D.; White, B. D.; Maple, M. B.

    2015-09-01

    Electrical resistivity measurements on La1 -xSmxO0.5F0.5BiS2 (x =0.1 ,0.3 ,0.6 ,0.8 ) have been performed under applied pressures up to 2.6 GPa from 2 K to room temperature. The superconducting transition temperature Tc of each sample significantly increases at a Sm-concentration-dependent pressure Pt, indicating a pressure-induced phase transition from a low-Tc to a high-Tc phase. At ambient pressure, Tc increases dramatically from 2.8 K at x =0.1 to 5.4 K at x =0.8 ; however, the Tc values at P >Pt decrease slightly with x , and Pt shifts to higher pressures with Sm substitution. In the normal state, semiconducting-like behavior is suppressed, and metallic conduction is induced with increasing pressure in all of the samples. These results suggest that the pressure dependence of Tc for the BiS2-based superconductors is related to the lattice parameters at ambient pressure and enable us to estimate the evolution of Tc for SmO0.5F0.5BiS2 under pressure.

  9. Location of trivalent lanthanide dopant energy levels in (Lu{sub 0.5}Gd{sub 0.5}){sub 2}O{sub 3}

    SciTech Connect

    Retot, H.; Viana, B.; Bessiere, A.; Galtayries, A.

    2011-06-15

    The location of Ln{sup 3+} dopant energy levels relative to bands in (Lu{sub 0.5}Gd{sub 0.5}){sub 2}O{sub 3} was studied. A several-steps analysis of XPS measurements on heavy lanthanides sesquioxides Ln{sub 2}O{sub 3} (Ln = Gd, Tb, Dy, Er, Tm, Yb, Lu) and on Sc{sub 2}O{sub 3} and Y{sub 2}O{sub 3} reference materials were used to locate Ln{sup 3+} dopant ground state relative to the top of the valence band in (Lu{sub 0.5}Gd{sub 0.5}){sub 2}O{sub 3} within an error bar of {+-}0.4 eV. The agreement between XPS data and model was found improved relative to previous studies. When compared to XPS analysis, prediction based on optical absorption shows a slight underestimation attributed to the lack of precision in Ce{sup 4+} charge transfer band measurement.

  10. Synthesis, Structure, and Electrochemical Performance of High Capacity Li2Cu0.5Ni0.5O2 Cathodes

    DOE PAGESBeta

    Ruther, Rose E; Zhou, Hui; Dhital, Chetan; Saravanan, Kuppan; Kercher, Andrew K.; Chen, Guoying; Huq, Ashfia; Delnick, Frank M.; Nanda, Jagjit

    2015-09-08

    Orthorhombic Li2NiO2, Li2CuO2, and solid solutions thereof have been studied as potential cathode materials for lithium-ion batteries due to their high theoretical capacity and relatively low cost. While neither endmember shows good cycling stability, the intermediate composition, Li2Cu0.5Ni0.5O2, yields reasonably high reversible capacities. A new synthetic approach and detailed characterization of this phase and the parent Li2CuO2 are presented. The cycle life of Li2Cu0.5Ni0.5O2 is shown to depend critically on the voltage window. The formation of Cu1+ at low voltage and oxygen evolution at high voltage limit the electrochemical reversibility. In situ X-ray absorption spectroscopy (XAS), in situ Raman spectroscopy,more » and gas evolution measurements are used to follow the chemical and structural changes that occur as a function of cell voltage.« less

  11. Synthesis of FeNi3/(Ni0.5Zn0.5)Fe2O4 nanocomposite and its high frequency complex permeability

    NASA Astrophysics Data System (ADS)

    Lu, Xuegang; Liang, Gongying; Zhang, Yumei; Zhang, Wei

    2007-01-01

    FeNi3/(Ni0.5Zn0.5)Fe2O4 nanocomposite particles were successfully synthesized using the hydrazine reduction combined with ammonia co-precipitation ferrite coating method. The x-ray and transmission electron microscopy analysis showed that face-centred cubic-structured FeNi3 nanoparticles were coated with spinel Ni-Zn ferrite. The composite particles were nearly spherical with diameters of about 80-200 nm and exhibited typical soft magnetic properties. The saturation magnetization (Ms) of the composite was greatly improved, compared with that of traditional ferrite. With increasing ferrite content, the eddy-current loss was effectively suppressed and a notable high frequency characteristic, in which the real part μ' of the permeability was almost independent of the frequency, was observed. The imaginary part μ'' remained at an extremely low value below the frequency of 300 MHz. The cut-off frequency fr was estimated to be above 1 GHz. The highest value of μ' reached 13 when the ratio of FeNi3 to Ni0.5Zn0.5Fe2O4 was 1:1. Two peaks were observed in the permeability spectra, which may be ascribed to the ferromagnetic resonances of FeNi3 and Ni-Zn ferrite respectively.

  12. Poling-Written Ferroelectricity in Bulk Multiferroic Double-Perovskite BiFe0.5Mn0.5O3.

    PubMed

    Delmonte, Davide; Mezzadri, Francesco; Gilioli, Edmondo; Solzi, Massimo; Calestani, Gianluca; Bolzoni, Fulvio; Cabassi, Riccardo

    2016-06-20

    We present a comprehensive study of the electrical properties of bulk polycrystalline BiFe0.5Mn0.5O3, a double perovskite synthesized in high-pressure and high-temperature conditions. BiFe0.5Mn0.5O3 shows an antiferromagnetic character with TN = 288 K overlapped with an intrinsic antiferroelectricity due to the Bi(3+) stereochemical effect. Beyond this, the observation of a semiconductor-insulator transition at TP ≈ 140 K allows one to define three distinct temperature ranges with completely different electrical properties. For T > TN, electric transport follows an ordinary thermally activated Arrhenius behavior; the system behaves as a paramagnetic semiconductor. At intermediate temperatures (TP < T < TN), electric transport is best described by Mott's variable range hopping model with lowered dimensionality D = 1, stabilized by the magnetic ordering process and driven by the inhomogeneity of the sample on the B site of the perovskite. Finally, for T < TP, the material becomes a dielectric insulator, showing very unusual poling-induced soft ferroelectricity with high saturation polarization, similar to the parent compound BiFeO3. Under external electric poling, the system irreversibly evolves from antiferroelectric to polar arrangement. PMID:27247990

  13. Enhanced photocatalytic activity over Cd0.5Zn0.5S with stacking fault structure combined with Cu2+ modified carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Gong, Beini; Lu, Yonghong; Wu, Pingxiao; Huang, Zhujian; Zhu, Yajie; Dang, Zhi; Zhu, Nengwu; Lu, Guining; Huang, Junyi

    2016-03-01

    For enhanced photocatalytic performance of visible light responsive CdZnS, a series of Cd0.5Zn0.5S solid solutions were fabricated by different methods. It was found that the semiconductor obtained through the precipitation-hydrothermal method (CZS-PH) exhibited the highest photocatalytic hydrogen production rate of 2154 μmol h-1 g-1. The enhanced photocatalytic hydrogen production of CZS-PH was probably due to stacking fault formation as well as narrow bandgap, a large surface area and a small crystallite size. Based on this, carbon nanotubes modified with Cu2+ (CNTs (Cu)) were used as a cocatalyst for CZS-PH. The addition of CNTs (Cu) enhanced notably the absorption of the composites for visible light. The highest photocatalytic hydrogen production rate of the Cd0.5Zn0.5S-CNTs (Cu) composite was 2995 μmol h-1 g-1 with 1.0 wt.% of CNTs (Cu). The improvement of the photocatalytic activity by loading of CNTs (Cu) was not due to alteration of bandgap energy or surface area, and was probably attributed to suppression of the electron-hole recombination by the CNTs, with Cu2+ anchored in the interface optimizing the photogenerated electron transfer pathway between the semiconductor and CNTs. We report here the successful combination of homojunction and heterojunction in CdZnS semiconductor, which resulted in promotion of charge separation and enhanced photocatalytic activity.

  14. Superparamagnetic state by linear and non-linear AC magnetic susceptibility in Mn0.5Zn0.5Fe2O4 ferrites nanoparticles.

    PubMed

    Suneetha, T; Kundu, S; Kashyap, Subhash C; Gupta, H C; Nath, T K

    2013-01-01

    The Mn0.5Zn0.5Fe2O4 nanoparticles has been synthesized using citrate-gel-precursor method. The direct mixing of nitrates and acetates yields homogeneous nanoparticles. Phase formation and crystal structure of the synthesized powder were examined through the X-ray diffraction (XRD). Fourier transform infrared (FTIR) spectra of the sample confirm the spinel structure. The average particle size was determined by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The average particle size is found to be about 13 nm. Superparamagnetic-like nature of the nanoparticles of Mn0.5Zn0.5Fe2O4 has been revealed through various dc and linear and non-linear ac magnetization measurements. However, the nanoparticles do not behave like ideal non-interacting superparamagnets. The magnetic particle size is found to be about 8 nm with saturation magnetization about 18.1 emu/g. The blocking temperature (T(B)) of the nanoparticle assembly is found to be about 150 K as observed from dc and ac magnetization measurements. The frequency dependence of the blocking temperature (T(B)) is found to follow Vogel-Fulcher law. The associated characteristic time tau0 is found to be 10(-5) s. This value is different from that generally found for non-interacting superparamagnetic (SPM) systems (tau0 = 10(-9)-10(-10) s). PMID:23646726

  15. Sintering behavior and dielectric properties of Bi3+-substituted Nd(Zn0.5Ti0.5)O3 microwave ceramics

    NASA Astrophysics Data System (ADS)

    Hu, Mingzhe; Ding, Zhao; Xiong, Gang; Ji, Denghui; Zhang, Kesheng

    2015-12-01

    The sintering behavior and dielectric properties of Bi3+-substituted Nd(Zn0.5Ti0.5)O3 (abbreviated as NZT) microwave ceramics (Nd1-xBix)(Zn0.5Ti0.5)O3 (0 ≤ x ≤ 0.15) (abbreviated as NBZT) are investigated. XRD results reveal the formation of single perovskite solid solutions for x ≤ 0.05 samples. For x > 0.05 samples, pyrochlore phase begins to segregate from the perovskite phase and its volume fraction increases with x. B-site Zn2+/Ti4+ 1:1 long range order (LRO) is detected by Raman Spectroscopy. The degree of LRO varies as a function of sintering conditions and chemical composition. The microwave dielectric properties of the composition are measured. By substituting Bi3+ for Nd3+, the temperature coefficient of resonant frequency (τf) tunes toward zero, however, the microwave quality factor, (Qf) deteriorates. For x = 0.03, τf reaches a minimum value of -18.9ppm/∘C with relative permittivity of ɛr = 48.2 and Qf = 1430GHz, respectively. The effect of Bi-doping on the Qf value is discussed.

  16. Electrical Characteristics and Preparation of (Ba0.5Sr0.5)TiO3 Films by Spray Pyrolysis and Rapid Thermal Annealing

    NASA Astrophysics Data System (ADS)

    Koo, Horng-Show; Chen, Mi; Ku, Hong-Kou; Kawai, Tomoji

    2007-04-01

    Functional films of (Ba0.5Sr0.5)TiO3 on Pt (1000 Å)/Ti (100 Å)/SiO2 (2000 Å)/Si substrates are prepared by spray pyrolysis and subsequently rapid thermal annealing. Barium nitrate, strontium nitrate and titanium isopropoxide are used as starting materials with ethylene glycol as solvent. For (Ba0.5Sr0.5)TiO3 functional thin film, thermal characteristics of the precursor powder scratched from as-sprayed films show a remarkable peak around 300-400 °C and 57.7% weight loss up to 1000 °C. The as-sprayed precursor film with coffee-like color and amorphous-like phase is transformed into the resultant film with white, crystalline perovskite phase and characteristic peaks (110) and (100). The resultant films show correspondent increases of dielectric constant, leakage current and dissipation factor with increasing annealing temperatures. The dielectric constant is 264 and tangent loss is 0.21 in the resultant films annealed at 750 °C for 5 min while leakage current density is 1.5× 10-6 A/cm2 in the film annealed at 550 °C for 5 min.

  17. The role of chemical structure on the magnetic and electronic properties of Co2FeAl0.5Si0.5/Si(111) interface

    NASA Astrophysics Data System (ADS)

    Kuerbanjiang, Balati; Nedelkoski, Zlatko; Kepaptsoglou, Demie; Ghasemi, Arsham; Glover, Stephanie E.; Yamada, Shinya; Saerbeck, Thomas; Ramasse, Quentin M.; Hasnip, Philip J.; Hase, Thomas P. A.; Bell, Gavin R.; Hamaya, Kohei; Hirohata, Atsufumi; Lazarov, Vlado K.

    2016-04-01

    We show that Co2FeAl0.5Si0.5 film deposited on Si(111) has a single crystal structure and twin related epitaxial relationship with the substrate. Sub-nanometer electron energy loss spectroscopy shows that in a narrow interface region there is a mutual inter-diffusion dominated by Si and Co. Atomic resolution aberration-corrected scanning transmission electron microscopy reveals that the film has B2 ordering. The film lattice structure is unaltered even at the interface due to the substitutional nature of the intermixing. First-principles calculations performed using structural models based on the aberration corrected electron microscopy show that the increased Si incorporation in the film leads to a gradual decrease of the magnetic moment as well as significant spin-polarization reduction. These effects can have significant detrimental role on the spin injection from the Co2FeAl0.5Si0.5 film into the Si substrate, besides the structural integrity of this junction.

  18. Oxygen-Vacancy-Induced Antiferromagnetism to Ferromagnetism Transformation in Eu0.5Ba0.5TiO3−δ Multiferroic Thin Films

    PubMed Central

    Li, Weiwei; Zhao, Run; Wang, Le; Tang, Rujun; Zhu, Yuanyuan; Lee, Joo Hwan; Cao, Haixia; Cai, Tianyi; Guo, Haizhong; Wang, Can; Ling, Langsheng; Pi, Li; Jin, Kuijuan; Zhang, Yuheng; Wang, Haiyan; Wang, Yongqiang; Ju, Sheng; Yang, Hao

    2013-01-01

    Oxygen vacancies (VO) effects on magnetic ordering in Eu0.5Ba0.5TiO3−δ (EBTO3−δ) thin films have been investigated using a combination of experimental measurements and first-principles density-functional calculations. Two kinds of EBTO3−δ thin films with different oxygen deficiency have been fabricated. A nuclear resonance backscattering spectrometry technique has been used to quantitatively measure contents of the VO. Eu0.5Ba0.5TiO3 ceramics have been known to exhibit ferroelectric (FE) and G-type antiferromagnetic (AFM) properties. While, a ferromagnetic (FM) behavior with a Curie temperature of 1.85 K has been found in the EBTO3−δ thin films. Spin-polarized Ti3+ ions, which originated from the VO, has been proven to mediate a FM coupling between the local Eu 4f spins and were believed to be responsible for the great change of the magnetic ordering. Considering the easy formation of VO, our work opens up a new avenue for achieving co-existence of FM and FE orders in oxide materials. PMID:24018399

  19. Superparamagnetic behavior of heat treated Mg0.5Zn0.5Fe2O4 ferrite nanoparticles studied by Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Srinivas, Ch.; Singh, S. B.; Tirupanyam, B. V.; Meena, S. S.; Yusuf, S. M.; Prasad, S. A. V.; Krishna, K. S. Rama; Sastry, D. L.

    2016-05-01

    Nanoparticles of Mg0.5Zn0.5Fe2O4 ferrite have been synthesized by co-precipitation method. XRD and Mössbauer spectroscopic results of Mg0.5Zn0.5Fe2O4 annealed at 200 °C, 500 °C and 800 °C are reported. It was observed that the crystallite size increases and the lattice parameter decreases with increase in annealing temperature. The observed decrease in lattice strain supports the increase in crystallite size. The Mössbauer spectra of the samples annealed at 200 °C and 500 °C exhibits superparamagnetic doublets whereas the Mössbauer spectrum of the sample annealed at 800 °C exhibits paramagnetic doublet along with weak sextet of hyperfine interaction. The values of isomer shift resemble the presence of high spin iron ions. The studied ferrite nanoparticles are suitable for biomedical applications. The results are incorporated employing core-shell model and cation redistribution.

  20. Enhancement of transition temperature in Fe{sub x}Se{sub 0.5}Te{sub 0.5} film via iron vacancies

    SciTech Connect

    Zhuang, J. C.; Yeoh, W. K. E-mail: zxshi@seu.edu.cn; Cui, X. Y.; Ringer, S. P.; Kim, J. H.; Shi, D. Q.; Wang, X. L.; Dou, S. X.; Shi, Z. X. E-mail: zxshi@seu.edu.cn

    2014-06-30

    The effects of iron deficiency in Fe{sub x}Se{sub 0.5}Te{sub 0.5} thin films (0.8 ≤ x ≤ 1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (T{sub C}) up to 21 K was observed in the most Fe deficient film (x = 0.8). Based on the observed and simulated structural variation results, there is a high possibility that Fe vacancies can be formed in the Fe{sub x}Se{sub 0.5}Te{sub 0.5} films. The enhancement of T{sub C} shows a strong relationship with the lattice strain effect induced by Fe vacancies. Importantly, the presence of Fe vacancies alters the charge carrier population by introducing electron charge carriers, with the Fe deficient film showing more metallic behavior than the defect-free film. Our study provides a means to enhance the superconductivity and tune the charge carriers via Fe vacancy, with no reliance on chemical doping.

  1. Dual Extraction of Photogenerated Electrons and Holes from a Ferroelectric Sr0.5Ba0.5Nb2O6 Semiconductor.

    PubMed

    Fan, Dayong; Zhu, Jian; Wang, Xiuli; Wang, Shengyang; Liu, Yong; Chen, Ruotian; Feng, Zhaochi; Fan, Fengtao; Li, Can

    2016-06-01

    The separation of photogenerated charges is a critical factor in photocatalysis. Recently, anomalous photovoltaic (APV) field effects (Voc ∼ 10(3) V/cm) in ferroelectrics, with their strong driving force for charge separation, have attracted much attention in photocatalysis and photoelectrocatalysis. However, it is still unknown whether photogenerated electrons and holes can be simultaneously extracted by the strong driving force toward the surface of ferroelectrics and can become available for surface reactions. This issue becomes critically important in photocatalysis because the surface reaction utilizes both the electrons and holes that reach the surface. In this work, a model lateral symmetric structure, metal/Sr0.5Ba0.5Nb2O6/metal (metal = Ag or Pt), as an electrode was fabricated. The dual extractions of photogenerated electrons and holes on the two opposite metal electrodes were achieved, as revealed by photovoltaic and ferroelectrical hysteresis measurements and photoassisted Kelvin probe force microscopy (KPFM). It was found that the high Schottky barriers of the two opposite Sr0.5Ba0.5Nb2O6-Pt electrodes are key factors that alter the two space charge regions (SCRs) by a poling effect. The resulting built-in electrical fields with parallel directions near both electrodes significantly enhance the charge separation ability. Our model unravels the driving force of charge separation in ferroelectric semiconductors, thus demonstrating the potential for highly efficient charge separation in photocatalysis. PMID:27183145

  2. Structure and magnetic properties of the perovskite YCo{sub 0.5}Fe{sub 0.5}O{sub 3}

    SciTech Connect

    Wei, Yingfen; Gui, Hong; Zhao, Zhenjie; Xie, Wenhui; Li, Junrui; Li, Xiaohong; Liu, Yong; Xin, Shengwei

    2014-12-15

    Y Co{sub 0.5}Fe{sub 0.5}O{sub 3}, in a structure of perovskite, has been successfully prepared with citrate precursors at 950-1100 °C in air by the sol-gel method. The X-ray diffraction patterns show that the samples are orthorhombic within the space group Pnma, where the Co and Fe ions are disordered at the 4b crystallographic sites. The crystal structure refinement undertaken by the Rietveld method has shown that the distortion of Co(Fe)O{sub 6} octahedra are large, where the ratio of Co/Fe-O bonding length along a axis to that in the bc plane is about 1.07. Such a large crystal lattice distortion implies a strong lattice-magnetism coupling, which may be utilized in the magnetoelectric devices. Magnetic measurement indicates that the Y Co{sub 0.5}Fe{sub 0.5}O{sub 3} is antiferromagnetic but showing weak ferromagnetism. We find that Fe{sup 3+} ions are in high-spin states, while Co{sup 3+} ions are in low-spin states which do not contribute to the magnetism. Both Fe{sup 3+} and Co{sup 3+} ions are not Jahn-Teller activated although the lattice distortion is large.

  3. Epitaxial Ferroelectric Ba(0.5)Sr(0.5)TiO3 Thin Films for Room-Temperature High-Frequency Tunable Element Applications

    NASA Technical Reports Server (NTRS)

    Chen, C. L.; Feng, H. H.; Zhang, Z.; Brazdeikis, A.; Miranda, F. A.; VanKeuls, F. W.; Romanofsky, R. R.; Huang, Z. J.; Liou, Y.; Chu, W. K.; Chu, C. W.

    1999-01-01

    Perovskite Ba(0.5)SR(0.5)TiO3 thin films have been synthesized on (001) LaAl03 substrates by pulsed laser ablation. Extensive X-ray diffraction, rocking curve, and pole-figure studies suggest that the films are c-axis oriented and exhibit good in-plane relationship of <100>(sub BSTO)//<100>(sub LAO). Rutherford Backscattering Spectrometry studies indicate that the epitaxial films have excellent crystalline quality with an ion beam minimum yield chi(sub min) Of only 2.6 %. The dielectric property measurements by the interdigital technique at 1 MHz show room temperature values of the relative dielectric constant, epsilon(sub r), and loss tangent, tan(sub delta), of 1430 and 0.007 with no bias, and 960 and 0.001 with 35 V bias, respectively. The obtained data suggest that the as-grown Ba(0.5)SR(0.5)TiO3 films can be used for development of room-temperature high-frequency tunable elements.

  4. Aurivillius-Popper mixed superconductors in BiO--CuO--(Sr/sub 0. 5/, Ca/sub 0. 5/)O system

    SciTech Connect

    Fukuhara, M.; Bhalla, A.S.; Mulay, L.N.; Newnham, R.E.

    1989-03-01

    We report the effect of inhomogeneities on the electric resistivity and ac magnetic susceptibility in Aurivillius-like bismuth mixed phase oxides of the BiO--Cuo--(Sr/sub 0.5/, Ca/sub 0.5/)O system and propose a crystal structure of the major phase having highest T/sub c/. Nominal Aurivillius compositions with molar ratios of BiO/(Sr/sub 0.5/, Ca/sub 0.5/)O = 1/2 are superconductors with T/sub c/ ranging from 83 to 107 K, and are accompanied by a large expansion during sintering due to the formation of Kirkendall voids. T/sub c/ increases with decreasing of the c lattice parameter. An oxide BiSrCaCu/sub 2/O/sub x/ (n = 2) shows a maximum T/sub c/ value of 107 K and an onset of superconductivity at a much higher temperature. It seems that the structure of Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub x/ consists of an Aurivillius-like phase having two perovskite layers and a Popper mixed phase. The ac magnetic susceptibility showed an overall decrease in susceptibility with time up to 220 days. This appears to be related to the relief of intralattice strain.

  5. Structural, Dielectric, and Electrical Properties of Bi1- x Pb x Fe1- x (Zr0.5Ti0.5) x O3

    NASA Astrophysics Data System (ADS)

    Panda, Niranjan; Pattanayak, Samita; Choudhary, R. N. P.

    2015-12-01

    Polycrystalline samples of Bi1- x Pb x Fe1- x (Zr0.5Ti0.5) x O3 (BPFZTO) with x = 0.0, 0.2, 0.3, and 0.4 were prepared by high-temperature solid-state reaction. Preliminary structural analysis of calcined powders of the materials by use of x-ray powder diffraction confirmed formation of single-phase systems with the tetragonal structure. Room-temperature scanning electron micrographs of the samples revealed uniform distribution of grains of low porosity and different dimensions on the surface of the samples. The frequency-temperature dependence of dielectric and electric properties was studied by use of dielectric and complex impedance spectroscopy over a wide range of frequency (1 kHz to 1 MHz) at different temperatures (25-500°C). The dielectric constant of BiFeO3 (BFO) was enhanced by substitution with Pb(Zr0.5Ti0.5)O3 (PZT) whereas the dielectric loss of the BPFZTO compounds decreased with increasing PZT content. A significant contribution of both grains and grain boundaries to the electrical response of the materials was observed. The frequency-dependence of the ac conductivity of BPFZTO followed Jonscher's power law. Negative temperature coefficient of resistance behavior was observed for all the BPFZTO samples. Conductivity by thermally excited charge carriers and oxygen vacancies in the materials was believed to be of the Arrhenius-type.

  6. Temperature dependence of magneto-transport properties in Co2Fe(Ga0.5Ge0.5)/Cu lateral spin valves

    NASA Astrophysics Data System (ADS)

    Ikhtiar, Kasai, S.; Takahashi, Y. K.; Furubayashi, T.; Mitani, S.; Hono, K.

    2016-02-01

    The non-local spin signals of Co2Fe(Ga0.5Ge0.5)/Cu lateral spin valves with sub-micron size dimensions were measured with varying temperatures. The non-local spin signal reaches 54 mΩ at 4 K, while it degrades down to 13 mΩ at room temperature. Analysis based on the one-dimensional spin diffusion model clarifies the dominant source for degrading of the spin signal is suppression of the spin diffusion length in Cu, not the spin polarization, indicating Co2Fe(Ga0.5Ge0.5) keeps half-metallic nature even at room temperature. The temperature dependence of non-local spin signal was found to exhibit a downturn at 36 K. The presence of magnetic impurities, detrimental effect of which becomes more pronounced for diffusive transport in long Cu wires, is suggested to cause the observed downturn in non-local spin signals.

  7. [Synthesis and spectra characterization of nano-sized Ce(1-x)(Fe(0.5)La(0.5))xO(2-delta) solid solutions].

    PubMed

    Zhang, Guo-fang; Zhang, Yang-huan; Ge, Qi-lu; Zhang, Yin; Liu, Ling-sheng; Zhang, Lian-lian

    2011-12-01

    Ce(1-x)(Fe(0.5)La(0.5))xO(2-delta) solid solutions were obtained via hydrothermal method. The structure of the solid solutions and the cell parameters were characterized by XRD analysis technique, the electron transition properties and doping effectswere measured by UV-Vis diffraction spectrum and Raman spectrum technique. XRD results showed that Ce(1-x)(Fe(0.5)La(0.5))xO(2-delta) id solutions exhibited cubic fluorite structure till the doping content increased to 0.30. Tiny Fe2O3 phase was observed when x = 0.30. The particle size was kept nanoscaled, and location of different kind of doping ions in CeO2 lattice was discussed. By increasing the doping content, the cell parameter was kept increasing gradually till x = 0.18, then it remained almost constant. The UV-Vis diffraction spectrum analysis showed that the absorption threshold edge redshifted, the band gap energy decreased with increasing the doping content. The valence of Fe ions in the lattice of CeO2 was +3. The F2g Raman mode also showed a downshift, and the peak gradually became broader, which further proved the influence of the dopant. PMID:22295785

  8. Octahedral distortion induced magnetic anomalies in LaMn{sub 0.5}Co{sub 0.5}O{sub 3} single crystals

    SciTech Connect

    Manna, Kaustuv Elizabeth, Suja; Anil Kumar, P. S.; Bhadram, Venkata Srinu; Narayana, Chandrabhas

    2014-07-28

    Single crystals of LaMn{sub 0.5}Co{sub 0.5}O{sub 3} belonging to the ferromagnetic-insulator and distorted perovskite class were grown using a four-mirror optical float zone furnace. The as-grown crystal crystallizes into an orthorhombic Pbnm structure. The spatially resolved 2D Raman scan reveals a strain-induced distribution of transition metal (TM)–oxygen (O) octahedral deformation in the as-grown crystal. A rigorous annealing process releases the strain, thereby generating homogeneous octahedral distortion. The octahedra tilt by reducing the bond angle TM-O-TM, resulting in a decline of the exchange energy in the annealed crystal. The critical behavior is investigated from the bulk magnetization. It is found that the ground state magnetic behavior assigned to the strain-free LaMn{sub 0.5}Co{sub 0.5}O{sub 3} crystal is of the 3D Heisenberg kind. Strain induces mean field-like interaction in some sites, and consequently, the critical exponents deviate from the 3D Heisenberg class in the as-grown crystal. The temperature-dependent Raman scattering study reveals strong spin-phonon coupling and the existence of two magnetic ground states in the same crystal.

  9. Magnetic interactions in BiFe0.5Mn0.5O3 films and BiFeO3/BiMnO3 superlattices

    PubMed Central

    Xu, Qingyu; Sheng, Yan; Khalid, M.; Cao, Yanqiang; Wang, Yutian; Qiu, Xiangbiao; Zhang, Wen; He, Maocheng; Wang, Shuangbao; Zhou, Shengqiang; Li, Qi; Wu, Di; Zhai, Ya; Liu, Wenqing; Wang, Peng; Xu, Y. B.; Du, Jun

    2015-01-01

    The clear understanding of exchange interactions between magnetic ions in substituted BiFeO3 is the prerequisite for the comprehensive studies on magnetic properties. BiFe0.5Mn0.5O3 films and BiFeO3/BiMnO3 superlattices have been fabricated by pulsed laser deposition on (001) SrTiO3 substrates. Using piezoresponse force microscopy (PFM), the ferroelectricity at room temperature has been inferred from the observation of PFM hysteresis loops and electrical writing of ferroelectric domains for both samples. Spin glass behavior has been observed in both samples by temperature dependent magnetization curves and decay of thermo-remnant magnetization with time. The magnetic ordering has been studied by X-ray magnetic circular dichroism measurements, and Fe-O-Mn interaction has been confirmed to be antiferromagnetic (AF). The observed spin glass in BiFe0.5Mn0.5O3 films has been attributed to cluster spin glass due to Mn-rich ferromagnetic (FM) clusters in AF matrix, while spin glass in BiFeO3/BiMnO3 superlattices is due to competition between AF Fe-O-Fe, AF Fe-O-Mn and FM Mn-O-Mn interactions in the well ordered square lattice with two Fe ions in BiFeO3 layer and two Mn ions in BiMnO3 layer at interfaces. PMID:25766744

  10. A study on the wake-up effect of ferroelectric Hf0.5Zr0.5O2 films by pulse-switching measurement.

    PubMed

    Kim, Han Joon; Park, Min Hyuk; Kim, Yu Jin; Lee, Young Hwan; Moon, Taehwan; Kim, Keum Do; Hyun, Seung Dam; Hwang, Cheol Seong

    2016-01-21

    The appearance of ferroelectric (FE) and anti-ferroelectric (AFE) properties in HfO2-based thin films is highly intriguing in terms of both the scientific context and practical application in various electronic and energy-related devices. Interestingly, these materials showed a "wake-up effect", which refers to the increase in remanent polarization with increasing electric field cycling number before the occurrence of the fatigue effect. In this work, the wake-up effect from Hf0.5Zr0.5O2 was carefully examined by the pulse-switching experiment. In the pristine state, the Hf0.5Zr0.5O2 film mostly showed FE-like behavior with a small contribution from AFE-like distortion, which could be ascribed to the involvement of the AFE phase. The field cycling of only 100 cycles almost completely transformed the AFE phase into the FE phase by depinning the pinned domains. The influence of field cycling on the interfacial layer was also examined through the pulse-switching experiments. PMID:26511062

  11. Influence of epitaxial growth on phase competition in Pr 0.5Sr 0.5MnO 3 films

    NASA Astrophysics Data System (ADS)

    Chen, Liping; Chen, Yuansha; Ma, Yubin; Lian, Guijun; Zhang, Yan; Xiong, Guangcheng

    2012-03-01

    A series of Pr0.5Sr0.5MnO3 (PSMO) films with various thickness were epitaxially grown on substrates of (0 0 1)-oriented (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (LSAT), LaAlO3 (LAO) and SrTiO3 (STO), and (0 1 1)-oriented STO using pulse laser deposition. Influence of epitaxial growth on phase competition was investigated. A ferromagnetic metal to antiferromagnetic insulator (FMM-AFI) transition upon cooling is present in both largely compressed situations deposited on LAO (0 0 1) and tensile cases deposited on STO (0 0 1) but absent in little strained films grown on LSAT (0 0 1), indicating that the antiferromagnetic insulating state is favored by strains. On the other hand, the 400 nm films deposited on (0 1 1)-oriented STO as well as LAO substrates show FMM-AFI transition. These results reveal that both the orientation of epitaxial growth and substrate-induced strain affect the FMM-AFI transition.

  12. Multiferroicity and magnetoelectric coupling enhanced large magnetocaloric effect in DyFe{sub 0.5}Cr{sub 0.5}O{sub 3}

    SciTech Connect

    Yin, L. H.; Yang, J.; Dai, J. M.; Song, W. H.; Zhang, R. R.; Sun, Y. P.

    2014-01-20

    DyFe{sub 0.5}Cr{sub 0.5}O{sub 3} has been synthesized using a sol-gel method. It exhibits ferroelectricity at the antiferromagnetic ordering temperature T{sub N1}∼261 K. Large magnetocaloric effect (MCE) (11.3 J/kg K at 4.5 T) enhanced by magnetoelectric coupling due to magnetic field and temperature induced magnetic transition was observed. Temperature-dependent Raman study shows an anomalous behavior near T{sub N1} in the phonon modes related to the vibration of Dy atoms and stretching of CrO{sub 6}/FeO{sub 6} octahedra, suggesting the ferroelectricity in DyFe{sub 0.5}Cr{sub 0.5}O{sub 3} is associated with the spin-phonon coupling with respect to both Dy and Cr/Fe ions. These results suggest routes to obtain high-temperature multiferroicity and large MCE for practical applications.

  13. Optical properties of small GaN-Al0.5Ga0.5N quantum dots grown on (11-22) GaN templates

    NASA Astrophysics Data System (ADS)

    Sellés, Julien; Rosales, Daniel; Gil, Bernard; Cassabois, Guillaume; Guillet, Thierry; Brault, Julien; Damilano, Benjamin; Vennéguès, Philippe; de Mierry, Philippe; Massies, Jean

    2015-03-01

    GaN/Al0.5Ga0.5N quantum dots deposited on the (11-22) plane have been grown by combining Molecular Beam Epitaxy (MBE) and Metal Organic Vapor Phase Epitaxy (MOVPE). The (11-22) GaN oriented template was realized by MOVPE starting from a M-plane oriented sapphire substrate. The average dot sizes are the following: between 15 and 20 nm in the <-1-123> and <1-100> directions and a height ranging between 0.8 and 1.4 nm. Their density is ranging between 2 and 8x1010cm-2. The crystal field splitting is measured in Al0.5Ga0.5N via polarized microphotoluminescence. We study the photoluminescence properties of small quantum dots which present innovative optical properties among which are the evolution of the polarization of the emitted photons at different temperatures. We also analyze the distortion of the photoluminescence at different time delays after the excitation pulse. A redshift is found that is attributed to the complex thermally-induced delocalization of the carriers through the assembly of dots from the smaller ones to the bigger ones.

  14. Large electrostrain and high optical temperature sensitivity in BaTiO3-(Na0.5Ho0.5)TiO3 multifunctional ferroelectric ceramics.

    PubMed

    Li, Jun; Chai, Xiaona; Wang, Xusheng; Xu, Chao-Nan; Gu, Yihao; Zhao, Haifeng; Yao, Xi

    2016-08-01

    Ferroelectric (1 -x)BaTiO3-x(Na0.5Ho0.5)TiO3 ceramics with ferroelectric and up-conversion luminescent multifunctions were designed and fabricated by a solid state reaction process. Their structure, ferroelectric, piezoelectric, up-conversion photoluminescence and relative optical temperature sensing properties were investigated systematically. Crystal structure analysis and Rietveld refinements based on the powder X-ray diffraction data show that the ceramics crystallized in the tetragonal perovskite space group P4mm at room temperature. Enhanced electrical properties and strong green up-conversion luminescence with thermally coupled green emission bands centered at 523 and 553 nm were observed. For a typical sample x equals 0.05, a large electrostrain of 0.279% was obtained under a 70 kV cm(-1) electric field that is comparable to that of the PZT4. Meanwhile, the excellent optical temperature sensitivity (0.0063 K(-1) at 480 K) is higher than that of Er-doped BaTiO3 nanocrystal materials. The results suggest that the BaTiO3-(Na0.5Ho0.5)TiO3 material should be an attractive material for piezoelectric actuator and temperature sensing device applications. PMID:27244098

  15. Improved bipolar resistive switching memory characteristics in Ge0.5Se0.5 solid electrolyte by using dispersed silver nanocrystals on bottom electrode.

    PubMed

    Kim, Jang-Han; Nam, Ki-Hyun; Hwang, Inchan; Cho, Won-Ju; Park, Byoungchoo; Chung, Hong-Bay

    2014-12-01

    Resistive switching random-access memory (ReRAM) devices based on chalcogenide solid electrolytes have recently become a promising candidate for future low-power nanoscale nonvolatile memory application. The resistive switching mechanism of ReRAM is based on the formation and rupture of conductive filament (CF) in the chalcogenide solid electrolyte layers. However, the random diffusion of metal ions makes it hard to control the CF formation, which is one of the major obstacles to improving device performance of ReRAM devices. We demonstrate the spin-coated metal nanocrystals (NCs) enhance the bipolar resistive switching (BRS) memory characteristics. Compared to the Ag/Ge0.5Se0.5/Pt structure, excellent resistive switching memory characteristics were obtained from the Ag/Ge0.5Se0.5/Ag NCs/Pt structure. Ag NCs improve the uniformity of resistance values and reduce the reset voltage and current. A stable DC endurance (> 100 cycles) and a high data retention (> 10(4) sec) were achieved by spin coating the Ag NCs on the Pt bottom electrode for ReRAMs. PMID:25971090

  16. CdTe(1-x)Se(x)/Cd0.5Zn0.5S core/shell quantum dots: core composition and property.

    PubMed

    Yang, Ping; Cao, Yongqiang; Li, Xiaoyu; Zhang, Ruili; Liu, Ning; Zhang, Yulan

    2014-08-01

    Alloy CdTe(1-x)Se(x) quantum dots (QDs) have been fabricated by an organic route using Cd, Te and Se precursors in a mixture of trioctylamine and octadecylphosphonic acid at 280 °C. The variation of photoluminescence (PL) peak wavelength of the CdTe(1-x)Se(x) QDs compared with CdTe QDs confirmed the formation of an alloy structure. The Se component drastically affected the stability of CdTe(1-x)Se(x) QDs. A Cd0.5Zn0.5S shell coating on CdTe(1-x)Se(x) cores was carried out using oleic acid as a capping agent. CdTe(1-x)Se(x)/Cd0.5Zn0.5S core/shell QDs revealed dark red PL while a yellow PL peak was observed for the CdTe(1-x)Se(x) cores. The PL efficiency of the core/shell QDs was drastically increased (less than 1% for the cores and up to 65% for the core/shell QDs). The stability of QDs in various buffer solutions was investigated. Core/shell QDs can be used for biological applications because of their high stability, tunable PL and high PL efficiency. PMID:23946281

  17. Localization Effect on Pt-Loaded Ce0.5Zr0.5O2 Nanoparticles Inserted Into Mesoporous SBA-16 by Hydrothermal Processing.

    PubMed

    Yotou, Hiroaki; Okamoto, Takumi; Ito, Miho; Sekino, Tohru; Tanaka, Shun-Ichiro

    2015-09-01

    We succeeded to use hydrothermal treatment to insert prefabricated Pt-loaded Ce0.5Zr0.5O2 (PtCZ) nanoparticles into the mesopores of the SBA-16 mesoporous silica without disordering of the mesoporous structure. Samples prepared by the hydrothermal treatment exhibited superior oxygen storage capacity compared to that of simple dry mixed sample. The oxygen storage capacity of the hydrothermally treated PtCZ is attributed to the localized PtCZ nanoparticles inside the mesopores of the SBA-16. FTIR analysis suggested that the PtCZ nanoparticles inside the mesopores possess the Si-O-Zr linkages that are bonded to the inner walls of the SBA-16 host. This linkage is the key reason for the superior oxygen storage capacity of PtCZ localized in the mesopores by hydrothermal treatment. It is considered that the formation of the Si-O-Zr linkage in the hydrothermally treated samples resulted in crystalline distortions of Ce0.5Zr0.5O2 nanoparticles inside the mesopores, and which contribute to enhance the oxygen storage capacity of PtCZ. PMID:26716294

  18. Theoretical study of magnetic properties and x-ray magnetic circular dichroism of the ordered Fe{sub 0.5}Pd{sub 0.5} alloy

    SciTech Connect

    Galanakis, I.; Ostanin, S.; Alouani, M.; Dreysse, H.; Wills, J. M.

    2000-01-01

    A detailed theoretical study of magnetic and structural properties of Fe{sub 0.5}Pd{sub 0.5} ordered face-centered tetragonal (fct) alloy, using both the local spin density approximation (LSDA) and the generalized gradient approximation (GGA), is presented. The total energy surface as a function of the lattice parameters a and c shows a long valley where stable structures may exist. Our calculation using the GGA predicts a magnetic phase transition from perpendicular to parallel magnetization as a function of the lattice parameter, whereas LSDA favors always the [001] magnetization axis for all values of the lattice parameters. The spin and orbital magnetic moments and x-ray magnetic circular dichroism spectra are calculated for the easy [001] and the hard [100] magnetization axis and for three sets of experimental lattice parameters, and are compared to the available experimental results on these films. A supercell calculation for a 4 monolayer Fe{sub 0.5}Pd{sub 0.5} thin film produced similar results. While the spin magnetic moments are in fair agreement with experiment, the orbital magnetic moments are considerably underestimated. To improve the agreement with experiment we included an atomic orbital polarization term; however, the computed orbital moments scarcely changed. (c) 2000 The American Physical Society.

  19. Partial melting of lower crust at 10-15 kbar: constraints on adakite and TTG formation

    NASA Astrophysics Data System (ADS)

    Qian, Qing; Hermann, Jörg

    2013-06-01

    The pressure-temperature ( P- T) conditions for producing adakite/tonalite-trondhjemite-granodiorite (TTG) magmas from lower crust compositions are still open to debate. We have carried out partial melting experiments of mafic lower crust in the piston-cylinder apparatus at 10-15 kbar and 800-1,050 °C to investigate the major and trace elements of melts and residual minerals and further constrain the P- T range appropriate for adakite/TTG formation. The experimental residues include the following: amphibolite (plagioclase + amphibole ± garnet) at 10-15 kbar and 800 °C, garnet granulite (plagioclase + amphibole + garnet + clinopyroxene + orthopyroxene) at 12.5 kbar and 900 °C, two-pyroxene granulite (plagioclase + clinopyroxene + orthopyroxene ± amphibole) at 10 kbar and 900 °C and 10-12.5 kbar and 1,000 °C, garnet pyroxenite (garnet + clinopyroxene ± amphibole) at 13.5-15 kbar and 900-1,000 °C, and pyroxenite (clinopyroxene + orthopyroxene) at 15 kbar and 1,050 °C. The partial melts change from granodiorite to tonalite with increasing melt proportions. Sr enrichment occurs in partial melts in equilibrium with <20 wt% plagioclase, whereas depletions of Ti, Sr, and heavy rare earth elements (HREE) occur relative to the starting material when the amounts of residual amphibole, plagioclase, and garnet are >20 wt%, respectively. Major elements and trace element patterns of partial melts produced by 10-40 wt% melting of lower crust composition at 10-12.5 kbar and 800-900 °C and 15 kbar and 800 °C closely resemble adakite/TTG rocks. TiO2 contents of the 1,000-1,050 °C melts are higher than that of pristine adakite/TTG. In comparison with natural adakite/TTG, partial melts produced at 10-12.5 kbar and 1,000 °C and 15 kbar and 1,050 °C have elevated HREE, whereas partial melts at 13.5-15 kbar and 900-1,000 °C in equilibrium with >20 wt% garnet have depressed Yb and elevated La/Yb and Gd/Yb. It is suggested that the most appropriate P- T conditions for

  20. High Piezoelectric Response in (Li0.5Sm0.5)2+-Modified 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 Near the Nonergodic-Ergodic Relaxor Transition

    NASA Astrophysics Data System (ADS)

    Xu, Jiwen; Li, Qinglin; Zhou, Changrong; Zeng, Weidong; Xiao, Jianrong; Ma, Jiafeng; Yuan, Changlai; Chen, Guohua; Rao, Guanghui; Li, Xuqiong

    2016-06-01

    The (Bi0.5Na0.5)TiO3-BaTiO3 system is a promising Pb-free piezoelectric material to substitute for environmentally undesirable Pb-based ferroelectrics. However, understanding the origin of its high piezoelectric response is a fundamental issue that has remained unclear for decades. Here, complex ions (Li0.5Sm0.5)2+ were introduced to dictate the stability of the electrically-induced ferroelectric state in 0.93(Bi0.5Na0.5)1- x (Li0.5Sm0.5) x TiO3-0.07BaTiO3 relaxor ceramics. The applied electric field induces a phase transition from a non-ergodic state to a ferroelectric state as well as the realignment of ferroelectric domains. The non-ergodic relaxor state with x = 0-0.02 is accompanied by relatively high piezoelectric activity and the strongest piezoelectricity is observed near the crossover from the nonergodic to the ergodic state. The stable␣ferroelectric state cannot survive after the removal of the application electric field for the high doping level due to the enhancement of the random field, which is responsible for the rapid decrease of piezoelectric properties for x > 0.02 compositions.

  1. Phase structure and piezoelectric properties of (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 lead-free piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Xing, Jie; Tan, Zhi; Jiang, Laiming; Chen, Qiang; Wu, Jiagang; Zhang, Wen; Xiao, Dingquan; Zhu, Jianguo

    2016-01-01

    (1-x)K0.48Na0.52Nb0.95Sb0.05O3-x(Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 [(1-x)KNNS-xBNLCZ] lead-free piezoceramics were prepared by the conventional solid state sintering method. The effects of BNLCZ contents on their phase structure, microstructure, and piezoelectric properties were investigated. All the samples show a pure perovskite structure, and no secondary phases were formed in the detected range. The rhombohedral and tetragonal phases of (1-x)KNNS-xBNLCZ coexist in the composition range of 0.0325 ≤ x ≤ 0.0425 at room temperature. A remarkably strong piezoelectricity was obtained by the addition of appropriate BNLCZ contents. The excellent piezoelectric properties of the ceramics with x = 0.04 were obtained: d33 ˜ 485 pC/N, kp ˜ 48%, and TC ˜ 227 °C. All the results show that the introduction of (Bi0.5Na0.5)0.9(Li0.5Ce0.5)0.1ZrO3 is a very effective way to form the rhombohedral and tetragonal phase coexistence of potassium-sodium niobate-based ceramics, which can improve its piezoelectric properties.

  2. 77 FR 53892 - Determination That ALOXI (Palonosetron Hydrochloride) Capsules, 0.5 Milligram (Base), Were Not...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-04

    ...The Food and Drug Administration (FDA) has determined that ALOXI (palonosetron hydrochloride (HCl)) Capsules, 0.5 milligram (mg) (base), were not withdrawn from sale for reasons of safety or effectiveness. This determination will allow FDA to approve abbreviated new drug applications (ANDAs) for palonosetron HCl capsules, 0.5 mg (base), if all other legal and regulatory requirements are...

  3. Ethylene production by ODHE in catalytically modified Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) membrane reactors.

    PubMed

    Lobera, M Pilar; Escolástico, Sonia; Garcia-Fayos, Julio; Serra, José M

    2012-08-01

    Process intensification by the integration of membranes and high-temperature reactors offers several advantages with regard to conventional process schemes, that is, energy saving, safe operation, reduced plant/unit size, and higher process performance, for example, higher productivity, catalytic activity, selectivity, or stability. We present the study of oxidative dehydrogenation of ethane at 850 °C on a catalytic membrane reactor based on a mixed ionic-electronic conducting membrane. The surface of the membrane made of Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) has been activated by using different porous catalytic layers based on perovskites. The layer was deposited by screen printing, and the porosity and thickness was studied for the catalyst composition. The different catalyst formulations are based on partial substitution of A- and B-site atoms of doped strontium ferrite/cobaltites (A(0.6)Sr(0.4)Co(0.5)Fe(0.5)O(3-δ) and Ba(0.6)Sr(0.4)BO(3-δ)) and were synthesized by an ethylenediaminetetraacetic acid-citrate complexation route. The use of a disk-shaped membrane in the reactor enabled the direct contact of gaseous oxygen and hydrocarbons to be avoided, and thus, the ethylene content increased. High ethylene yields (up to ≈81 %) were obtained by using a catalytic coating based on Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ), which included macropores produced by the addition of graphite platelets into the screen-printing ink. The promising catalytic results obtained with this catalytically modified membrane reactor are attributed to the combination of 1) the high activity, as a result of the high temperature and oxygen species diffusing through the membrane; 2) the control of oxygen dosing and the low concentration of molecules in the gas phase; and 3) suitable fluid dynamics, which enables appropriate feed contact with the membrane and the rapid removal of products. PMID:22791570

  4. Redox centers evolution in phospho-olivine type (LiFe0.5Mn0.5 PO4) nanoplatelets with uniform cation distribution.

    PubMed

    Paolella, Andrea; Bertoni, Giovanni; Dilena, Enrico; Marras, Sergio; Ansaldo, Alberto; Manna, Liberato; George, Chandramohan

    2014-03-12

    In phospho-olivine type structures with mixed cations (LiM1M2PO4), the octahedral M1 and M2 sites that dictate the degree of intersites order/disorder play a key role in determining their electrochemical redox potentials. In the case of LiFexMn1-xPO4, for example, in micrometer-sized particles synthesized via hydrothermal route, two separate redox centers corresponding to Fe(2+)/Fe(3+) (3.5 V vs Li/Li(+)) and Mn(2+)/Mn(3+) (4.1 V vs Li/Li(+)), due to the collective Mn-O-Fe interactions in the olivine lattice, are commonly observed in the electrochemical measurements. These two redox processes are directly reflected as two distinct peak potentials in cyclic voltammetry (CV) and equivalently as two voltage plateaus in their standard charge/discharge characteristics (in Li ion batteries). On the contrary, we observed a single broad peak in CV from LiFe0.5Mn0.5PO4 platelet-shaped (∼10 nm thick) nanocrystals that we are reporting in this work. Structural and compositional analysis showed that in these nanoplatelets the cations (Fe, Mn) are rather homogeneously distributed in the lattice, which is apparently the reason for a synergetic effect on the redox potentials, in contrast to LiFe0.5Mn0.5PO4 samples obtained via hydrothermal routes. After a typical carbon-coating process in a reducing atmosphere (Ar/H2), these LiFe0.5Mn0.5PO4 nanoplatelets undergo a rearrangement of their cations into Mn-rich and Fe-rich domains. Only after such cation rearrangement (via segregation) in the nanocrystals, the redox processes evolved at two distinct potentials, corresponding to the standard Fe(2+)/Fe(3+) and Mn(2+)/Mn(3+) redox centers. Our experimental findings provide new insight into mixed-cation olivine structures in which the degree of cations mixing in the olivine lattice directly influences the redox potentials, which in turn determine their charge/discharge characteristics. PMID:24564785

  5. Structural and magnetic study of RFe{<_0.5}V{<_0.5}O{<_3} (R = Y, Eu, Nd, La) perovskite compounds.

    SciTech Connect

    Gateshki, M.; Suescun, L.; Kolesnik, S.; Mais, J.; Dabrowski, B.

    2011-06-01

    B-site disordered RFe{sub 0.5}V{sub 0.5}O{sub 3} compounds, with R=La, Nd, Eu and Y, have been prepared by solid-state reaction technique and their structures and magnetic properties have been investigated through X-ray powder diffraction, time-of-flight neutron powder diffraction and magnetization measurements at temperatures ranging from 5 to 700 K. The four compounds can be described as distorted perovskites with space group symmetry Pbnm and a{sup +}b{sup -}b{sup -} tilt system. The studied compounds also show antiferromagnetic ordering with Neel temperatures of 299, 304, 304, and 335 K respectively. The magnetic structures of R=La, Nd and Y compounds were determined from the neutron powder diffraction as Gz with observed magnetic moments of 2.55, 2.54 and 2.69 {mu}{sub B} at 30, 40 and 40 K, respectively.

  6. Flux Pinning by Cr Nanoparticles in Cu_{0.5} Tl_{0.5} Ba2 Ca2 Cu3 O_{10-δ } Superconductor

    NASA Astrophysics Data System (ADS)

    Waqee-ur-Rehman, M.; Mumtaz, M.; Qasim, Irfan; Nadeem, K.

    2016-04-01

    Increase in flux pinning strength of Cu_{0.5} Tl_{0.5} Ba2 Ca2 Cu3 O_{10-δ } (CuTl-1223) superconductor has been observed after addition of Cr nanoparticles. We have thoroughly investigated the infield response of Cr nanoparticles-added CuTl-1223 superconductor in an external applied magnetic field in the range of 0-7 T. Solid-state reaction technique has been employed to synthesize (Cr)x -CuTl-1223; x = 0-1.00 wt% nanoparticle-superconductor composites. The flux pinning mechanism has been analyzed on the basis of thermally activated flux flow model in the presence of a small current (10 μ A). The increase in activation energy and decrease in transition width of CuTl-1223 superconducting phase show the enhancement in its flux pinning strength upon the addition of Cr nanoparticles.

  7. Electronic structure of random Al sub 0. 5 Ga sub 0. 5 As alloys: Test of the special-quasirandom-structures'' description

    SciTech Connect

    Hass, K.C.; Davis, L.C. ); Zunger, A. )

    1990-08-15

    The spectral properties of an {ital sp}{sup 3}{ital s*} tight-binding Hamiltonian for a random, unrelaxed Al{sub 0.5}Ga{sub 0.5}As alloy are calculated using three different techniques: the coherent-potential approximation, the recursion method (as applied to a {gt}2000 atom supercell), and the recently introduced special-quasirandom-structures'' (SQS) approach. Over a broad range of scattering strengths, the dominant spectral features predicted by the first two techniques are well reproduced by calculations for an SQS with 16 atoms/unit-cell ( SQS-8''). This suggests that the SQS approach might also be useful in cases where the other methods are difficult to apply, e.g., in first-principles calculations for structurally relaxed alloys.

  8. Effect of Quenching on Magnetoresistance Properties in the Pr 0.5Sr 0.5MnO 3 Perovskite Manganite

    NASA Astrophysics Data System (ADS)

    Boujelben, W.; Ellouze, M.; Cheikh-Rouhou, A.; Pierre, J.; Joubert, J. C.

    2002-05-01

    We report on the magnetization, resistivity and magnetoresistance (MR) measurements on polycrystalline Pr0.5Sr0.5MnO3. Quenching samples from 1400°C to room temperature in water (sample I) or in air (sample II) leads to different behaviors. Powder X-ray diffraction patterns for samples I and II could be indexed, respectively, in rhombohedral perovskite structure with R3c space group and in the orthorhombic one with Imma space group. Magnetization measurements show that both samples exhibit a paramagnetic-ferromagnetic transition at 280 K (sample I) and 265 K (sample II). At low temperature, sampleI presents a ferromagnetic spin-canted state, while sample II behaves as an antiferromagnet below 160 K. Resistivity and magnetoresistance studies show a net difference as a function of the quenching conditions.

  9. Dielectric Properties of SrMnO3-doped K0.5Na0.5NbO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Deng, Jianming; Sun, Xiaojun; Liu, Laijun; Liu, Saisai; Huang, Yanmin; Fang, Liang; Elouadi, Brahim

    2016-05-01

    (1-x)K0.5Na0.5NbO3-xSrMnO3 (0.02 ≤ x ≤ 0.08) (KNN-xSM) ceramics were fabricated by a conventional solid-state technique. X-ray diffraction of the samples revealed that the crystal structure changes from orthorhombic to tetragonal, and finally to pseudocubic symmetry with increasing x. Temperature dependence of dielectric properties showed that the temperature (T m) corresponding to the maximum of dielectric permittivity decreased with increasing x. Two dielectric relaxation processes occurred at high temperatures, which were attributed to grain and grain boundary responses, respectively. Polarization hysteresis loops (P-E) at different electrical fields were displayed. P rmax degenerated with the increase of SM due to the thermally activated leakage current increases. The relationship between electrical properties and defect compensation mechanism is discussed.

  10. Ordering of the heavy anions in mixed BaFBr{sub 0.5}I{sub 0.5} crystals: Experimental results

    SciTech Connect

    Rey, J.M.; Bill, H.; Hagemann, H.; Kubel, F.

    2005-11-01

    Mixed matlokite hosts of composition BaFBr{sub x}I{sub 1-x}(0{<=}x{<=}1) (pure and doped with Sm{sup 2+}, Eu{sup 2+}) were studied with x-ray crystallography, luminescence, Raman, and electron paramagnetic resonance (EPR) spectroscopy. Results are presented for BaFBr{sub 0.5}I{sub 0.5} which demonstrate that a ferrielectric domain structure is formed due to the fact that the heavy halogen ions form separate sublattices with randomly distributed domain walls. The space group of a domain is P4 mm (No. 99). The EPR data from Eu{sup 2+} allowed to determine the volume fraction of domains.

  11. Temperature dependence of optical properties (3HgSe)0.5(In2Se3)0.5, doped with Mn or Fe

    NASA Astrophysics Data System (ADS)

    Koziarskyi, I. P.; Marianchuk, P. D.; Maistruk, E. V.; Koziarskyi, D. P.

    2012-01-01

    The values of refraction index, the main reflection index and reflection coefficient for the investigated crystals were determined on the basis of the study of reflection and transmission coefficients of (3HgSe)0.5(In2Se3)0.5 crystals doped with Mn or Fe. The investigation was carried out on the wavelengths interval of 0.9<=λ<=26.6 μm. Basing on the dependencies α2 on the energy of incident electromagnetic radiation it was determined that in crystals the direct allowed interband optical transitions occur, and the value of the band gap was obtained. The influence of temperature on the optical transmittance has been studied in the interval of 120-300 K.

  12. Temperature dependence of optical properties (3HgSe)0.5(In2Se3)0.5, doped with Mn or Fe

    NASA Astrophysics Data System (ADS)

    Koziarskyi, I. P.; Marianchuk, P. D.; Maistruk, E. V.; Koziarskyi, D. P.

    2011-09-01

    The values of refraction index, the main reflection index and reflection coefficient for the investigated crystals were determined on the basis of the study of reflection and transmission coefficients of (3HgSe)0.5(In2Se3)0.5 crystals doped with Mn or Fe. The investigation was carried out on the wavelengths interval of 0.9<=λ<=26.6 μm. Basing on the dependencies α2 on the energy of incident electromagnetic radiation it was determined that in crystals the direct allowed interband optical transitions occur, and the value of the band gap was obtained. The influence of temperature on the optical transmittance has been studied in the interval of 120-300 K.

  13. Diffuse phase transition and high-temperature dielectric relaxation study on (Bi0.5Na0.5)1-xBaxTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Liu, Qiu-Xiang; Tang, Xin-Gui; Jiang, Yan-Ping; Yue, Jing-Long; Li, Jin-Kai

    2016-09-01

    Lead free (Bi0.5Na0.5)1-xBaxTiO3 (x=0.6, 0.7, 0.8, 0.9) ferroelectric ceramics were synthesized by the traditional solid state reaction method. Sintering was carried out at 1200 °C for 2 h in air atmosphere. The structural, microstructure and Ferroelectric of ceramics were investigated. In dielectric studies, a diffuse phase transition was exhibited and a dielectric relaxation behavious was observed at high temperature range. Impedance analysis characterized grain and grain boundaries resistivities of the ceramics and calculated activation energy and the activation energy for conduction. Polaron theory indicates that the relaxation of the samples at high temperatures was associated with the hopping ions caused by oxygen vacancies.

  14. Anisotropic magnetoresistance of epitaxial Pr{sub 0.5}Sr{sub 0.5}MnO{sub 3} film

    SciTech Connect

    Chen, X. G.; Yang, Y. B.; Wang, C. S.; Liu, S. Q.; Zhang, Y.; Han, J. Z.; Yang, Y. C.; Yang, J. B.

    2014-01-28

    The magnetic field and temperature dependent anisotropic magnetoresistance (AMR) of the epitaxial grown Pr{sub 0.5}Sr{sub 0.5}MnO{sub 3} thin films was investigated. It was found that the magnetoresistance exhibited the characteristics of magnetic polaron hopping. A two-fold symmetric AMR occurred in the ferromagnetic region (∼220 K < T < ∼150 K), while a four-fold symmetric AMR appeared under a high magnetic field in the antiferromagnetic orbital ordered region (T < ∼150 K). The angular dependence of the resistance showed a hysteresis effect under magnetic field at low temperature. It is believed that these phenomena are attributed to the spin canting effect, which originates from the melting of orbital ordering under the external magnetic field in the antiferromagnetic region.

  15. Growth and diode-pumped laser operation of Pr3+:β-(Y0.5,Gd0.5)F3 at various transitions.

    PubMed

    Werner Metz, Philip; Marzahl, Daniel-Timo; Guguschev, Christo; Bertram, Rainer; Kränkel, Christian; Huber, Günter

    2015-06-15

    We report on the crystal growth of the orthorhombic low-temperature β-phase of (Y0.5,Gd0.5)F3 (YGF) single crystals. The crystals were activated with trivalent praseodymium (Pr3+) and characterized with respect to their ground state absorption and stimulated emission properties. Under InGaN-laser-diode pumping, laser oscillation was obtained at more than ten wavelengths in the green, orange, red, and dark red spectral regions. In these initial experiments, output powers exceeding 100 mW and slope efficiencies between 10% and 30% were obtained. To the best of our knowledge, these results represent the first application of YGF crystals as laser host material for any active ion. PMID:26076240

  16. Effect of pressure-driven local structural rearrangement on the superconducting properties of FeSe0.5Te0.5

    NASA Astrophysics Data System (ADS)

    Bendele, M.; Guguchia, Z.; von Rohr, F.; Irifune, T.; Shinmei, T.; Kantor, I.; Pascarelli, S.; Joseph, B.; Marini, C.

    2014-11-01

    The pressure dependence of the superconducting transition temperature Tc, the local structure, and the electronic properties of the iron chalcogenide superconductor FeSe0.5Te0.5 was investigated by means of SQUID magnetometry and site-selective polarized x-ray absorption spectroscopy at the iron and selenium K -edges. The measurements reveal a discontinuous decrease of the local bond distances by crossing a tetragonal to monoclinic structural phase transition at pS˜2.7 GPa. The electronic structure, however, evolves evenly, but the superconducting properties are highly affected by changes in the local structure. These results underline the close connection of the lattice and the superconductivity in the iron-based superconductors.

  17. Effect of sintering treatment on structural and magnetic properties of Ni0.5Co0.5Fe2O4 ferrites

    NASA Astrophysics Data System (ADS)

    Nandan, Brajesh; Bhatnagar, M. C.

    2016-05-01

    Two sets of Ni0.5Co0.5Fe2O4 ferrites were synthesized using sol-gel method. Both the samples were heat treated at different temperatures. The effect of sintering treatment analyzed on structural and magnetic properties. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used for structural analysis. Alternating gradient magnetometer (AGM) is used for magnetic measurements. In structural analysis, grains size is calculated using Debye - Scherrer's formula and Williamson-Hall (W-H) plot. From both the techniques, grain size is found nearly same and increased in size with increase sintering temperature. Increased particle size is confirmed from SEM micrographs. Strain value is calculated from intercept of W-H plot. In both the samples, compressive strain in nature is found. Magnetic properties were also varying under different heat treatment. The change in magnetic properties with change in structural change at different sintering treatment is discussed in this report.

  18. Evolution of photoinduced effects in phase-separated Sm0.5Sr0.5Mn1−yCryO3 thin films

    PubMed Central

    Chai, Xiaojie; Xing, Hui; Jin, Kexin

    2016-01-01

    Systematic study on electrical transport properties has been performed in Sm0.5Sr0.5Mn1−yCryO3 thin films illuminated by the light. An evolution of persistent and transient photoinduced effects induced by the impurity doping and temperature has been observed, which is closely related to the number of ferromagnetic clusters. The maximum persistent photoinduced effect is observed at y = 0.08 and the corresponding value is about 61.7% at the power density of 13.7 mW/mm2. The underlying mechanism can be understood by the coexistence and competition of the multiphases in phase-separated manganites induced by Cr-doping. These results would pave the way for practical applications in innovative photoelectric devices of all-oxides. PMID:27001006

  19. Effect of Oxygen-deficiencies on Resistance Switching in Amorphous YFe0.5Cr0.5O3−d films

    PubMed Central

    Wang, Xianjie; Hu, Chang; Song, Yongli; Zhao, Xiaofeng; Zhang, Lingli; Lv, Zhe; Wang, Yang; Liu, Zhiguo; Wang, Yi; Zhang, Yu; Sui, Yu; Song, Bo

    2016-01-01

    Herein, we demonstrate the contribution of the oxygen-deficiencies on the bipolar resistance switching (RS) properties of amorphous-YFe0.5Cr0.5O3−d (a-YFCO) films. The a-YFCO films were prepared under various oxygen pressures to tune the concentration of oxygen-deficiencies in the films. The XPS data verify that the oxygen-deficiencies increase with decreasing oxygen pressure. The RS property becomes more pronounced with more oxygen-deficiencies in a-YFCO films. Based on the Ohmic conduction measurements in the low resistance state, we confirm that the RS mechanism is related to the migration of oxygen-deficiencies. The enhanced RS and long retention in a-YFCO suggest a great potential for applications in nonvolatile memory devices. PMID:27452114

  20. Fundamental limitation to the magnitude of piezoelectric response of (001)pc textured K0.5Na0.5NbO3 ceramic

    SciTech Connect

    Gupta, Shashaank; Belianinov, Alex; Okatan, Mahmut B; Jesse, Stephen; Kalinin, Sergei V; Priya, Shashaank

    2014-01-01

    (001)pc textured K0.5Na0.5NbO3 (KNN) ceramic was found to exhibit a 65% improvement in the longitudinal piezoelectric response as compared to its random counterpart. Piezoresponse force microscopy study revealed the existence of larger 180 and non-180 domains for textured ceramic as compared to that of the random ceramic. Improvement in piezoresponse by the development of (001)pc texture is discussed in terms of the crystallographic nature of KNN and domain morphology. A comparative analysis performed with a rhombohedral composition suggested that the improvement in longitudinal piezoresponse of polycrystalline ceramics by the development of (001)pc texture is limited by the crystal structure.

  1. Formation of self-organized In 0.5Ga 0.5As quantum dots on GaAs by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Chyi, Jen-Inn; Nee, Tzer-En; Lee, Ching-Ting; Shieh, Jia-Lin; Pan, Jen-Wei

    1997-05-01

    Self-organized In 0.5Ga 0.5As quantum dots have been successfully grown on vicinal GaAs substrates by molecular beam epitaxy. The density of the quantum dots can be changed by nucleating the dots under different As overpressure. Substrate tilt angle of 15° results in much larger dot size and density than that of 4° due to the closely spaced step edges on the surface. Through investigations of the dots grown on In 0.1Ga 0.9As buffer, the strain energy of the buffer layer is also found to be an important factor that affects the size and density of the quantum dots.

  2. Synthesis and characterization of Mn0.5Zn0.5Fe2O4 and Fe3O4 nanoparticle ferrofluids for thermo-electric conversion

    NASA Astrophysics Data System (ADS)

    Sansom, C. L.; Jones, P.; Dorey, R. A.; Beck, C.; Stanhope-Bosumpim, A.; Peterson, J.

    2013-06-01

    Ferrofluids containing nanoparticles of Mn0.5Zn0.5Fe2O4 (MZ5) and Fe3O4 (magnetite) have been examined as potential thermal transport media and energy harvesting materials. The ferrofluids were synthesized by chemical co-precipitation and characterized by EDX to determine composition and by TEM to determine particle size and agglomeration. A range of particle coatings and carrier fluids were used to complete the fluid preparation. Commercially available ferrofluids were tested in custom built rigs to demonstrate both thermal pumping (for waste heat removal applications) and power induction (for power conversion and energy harvesting applications). The results indicate that simple ferrofluids possess the necessary properties to remove waste heat, either into thermal storage or for conversion to electrical power.

  3. Polarized neutron reflection study of the unidirectional magnetic anisotropy of Permalloy on Ni 0.5Co 0.5O

    NASA Astrophysics Data System (ADS)

    Felcher, G. P.; Huang, Y. Y.; Carey, M.; Berkowitz, A.

    1993-03-01

    Couples of ferromagnetic Permalloy/antiferromagnetic metal oxide exhibit unidirectional magnetic anisotropy along a magnetic field applied during cooling. Polarized neutron reflection has been used to check if the effect is due to a bias of the antiferromagnetic configuration in the oxide, where the layer immediately adjacent to the Permalloy is polarized parallel to the easy direction of magnetization. The measurements were made on a sample consisting of 300ÅPermalloy/500ÅNi 0.5Co 0.5O. Polarized neutron reflectivities were taken at the four corners of the magnetic hysteresis loop at 20 K. A faint magnetic signal consistent with the unidirectional bias of the F / AF structure was observed. This behavior is discussed in the light of the current theories.

  4. Correlation between electrical and magnetic properties of polycrystalline La0.5Ca0.5Mn0.98Bi0.02O3

    NASA Astrophysics Data System (ADS)

    Krichene, A.; Bourouina, M.; Venkateshwarlu, D.; Solanki, P. S.; Rayaprol, S.; Ganesan, V.; Boujelben, W.; Kuberkar, D. G.

    2016-06-01

    We have reported in this work the study of correlation between electrical transport and magnetic properties of La0.5Ca0.5Mn0.98Bi0.02O3 polycrystalline sample prepared by solid state method. Structural analysis reveals that presently studied compound crystallizes in the orthorhombic structure with Pnma space group. Temperature dependence of magnetization indicates that our studied compound undergoes a paramagnetic-ferromagnetic transition at Curie temperature TC=237 K. Magnetotransport analysis was successfully carried out using percolation model in the temperature range 40-300 K for magnetic field values up to 14 T. Strong correlation between electrical and magnetic properties was observed along with the absence of charge ordering inside the structure of our sample.

  5. Magnetoresistance reversal in antiperovskite compound Mn{sub 3}Cu{sub 0.5}Zn{sub 0.5}N

    SciTech Connect

    Zhang, X. H.; Yin, Y.; Yuan, Q.; Han, J. C.; Zhang, Z. H.; Jian, J. K.; Zhao, J. G. E-mail: songbo@hit.edu.cn; Song, B. E-mail: songbo@hit.edu.cn

    2014-03-28

    We report detailed investigations of the structure, magnetic properties, electronic transport, and specific heat in Mn-based antiperovskite compounds Mn{sub 3}Cu{sub 0.5}Zn{sub 0.5}N. Most strikingly, there are several fascinating features: (i) The magnetoresistance at 30 kOe (40 kOe) exceeds ∼1% (∼2%) over a temperature span of ∼70 K (∼25 K) from 5 to 140 K; (ii) magnetoresistance fluctuates at temperatures of 100–200 K, including an obvious sign reversal from negative to positive at ∼140 K. Analysis of the specific heat reveals that the magnetoresistance reversal may originate from the reconstruction of the Fermi surface accompanying an antiferromagnetic-ferromagnetic transition.

  6. Unexpected ferromagnetic ordering enhancement with crystallite size growth observed in La{sub 0.5}Ca{sub 0.5}MnO₃ nanoparticles

    SciTech Connect

    Iniama, G.; Ita, B. I.; Presa, P. de la Hernando, A.; Alonso, J. M.; Multigner, M.; Cortés-Gil, R.; Ruiz-González, M. L.; Gonzalez-Calbet, J. M.

    2014-09-21

    In this paper, the physical properties of half-doped manganite La{sub 0.5}Ca{sub 0.5}MnO₃ with crystallite sizes ranging from 15 to 40 nm are investigated. As expected, ferromagnetic order strengthens at expense of antiferromagnetic one as crystallite size is reduced to 15 nm. However, contrary to previously reported works, an enhancement of saturation magnetization is observed as crystallite size increases from 15 to 22 nm. This unexpected behavior is accompanied by an unusual cell volume variation that seems to induce ferromagnetic-like behavior at expense of antiferromagnetic one. Besides, field cooled hysteresis loops show exchange bias field and coercivity enhancement for increasing cooling fields, which suggest a kind of core-shell structure with AFM-FM coupling for crystallite sizes as small as 15 nm. It is expected that inner core orders antiferromagnetically, whereas uncompensated surface spins behave as spin glass with ferromagnetic-like ordering.

  7. Evolution of photoinduced effects in phase-separated Sm0.5Sr0.5Mn1-yCryO3 thin films.

    PubMed

    Chai, Xiaojie; Xing, Hui; Jin, Kexin

    2016-01-01

    Systematic study on electrical transport properties has been performed in Sm0.5Sr0.5Mn1-yCryO3 thin films illuminated by the light. An evolution of persistent and transient photoinduced effects induced by the impurity doping and temperature has been observed, which is closely related to the number of ferromagnetic clusters. The maximum persistent photoinduced effect is observed at y = 0.08 and the corresponding value is about 61.7% at the power density of 13.7 mW/mm(2). The underlying mechanism can be understood by the coexistence and competition of the multiphases in phase-separated manganites induced by Cr-doping. These results would pave the way for practical applications in innovative photoelectric devices of all-oxides. PMID:27001006

  8. Evolution of photoinduced effects in phase-separated Sm0.5Sr0.5Mn1‑yCryO3 thin films

    NASA Astrophysics Data System (ADS)

    Chai, Xiaojie; Xing, Hui; Jin, Kexin

    2016-03-01

    Systematic study on electrical transport properties has been performed in Sm0.5Sr0.5Mn1‑yCryO3 thin films illuminated by the light. An evolution of persistent and transient photoinduced effects induced by the impurity doping and temperature has been observed, which is closely related to the number of ferromagnetic clusters. The maximum persistent photoinduced effect is observed at y = 0.08 and the corresponding value is about 61.7% at the power density of 13.7 mW/mm2. The underlying mechanism can be understood by the coexistence and competition of the multiphases in phase-separated manganites induced by Cr-doping. These results would pave the way for practical applications in innovative photoelectric devices of all-oxides.

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

    SciTech Connect

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

    2015-11-01

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

  10. Observation of indium ion migration-induced resistive switching in Al/Mg0.5Ca0.5TiO3/ITO

    NASA Astrophysics Data System (ADS)

    Lin, Zong-Han; Wang, Yeong-Her

    2016-08-01

    Understanding switching mechanisms is very important for resistive random access memory (RRAM) applications. This letter reports an investigation of Al/Mg0.5Ca0.5TiO3 (MCTO)/ITO RRAM, which exhibits bipolar resistive switching behavior. The filaments that connect Al electrodes with indium tin oxide electrodes across the MCTO layer at a low-resistance state are identified. The filaments composed of In2O3 crystals are observed through energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, nanobeam diffraction, and comparisons of Joint Committee on Powder Diffraction Standards (JCPDS) cards. Finally, a switching mechanism resulting from an electrical field induced by In3+ ion migration is proposed. In3+ ion migration forms/ruptures the conductive filaments and sets/resets the RRAM device.

  11. Synthesis and characterization of Sm0.5Ba0.5MnO3-δ as anode materials for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Abdalla, A. M.; Radenahmad, N.; Abu Bakar, M. S.; . I. Petra, Pg M.; Azad, A. K.

    2016-03-01

    The material performance is a crucial issue in the current fuel cell technology, and for this reason we present this new series of Samarium family which can be used as electrode giving a high performance in a particular application. Sm0.5Ba0.5MnO3-δ was prepared by solid state reaction method and characterized by using X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Rietveld analysis of XRD data shows that the material has an Orthorhombic crystal structure with cell parameter a = 3.883(1) Å b = 3.8742(5) Å c = 7. 762(4) Å, in the Pmmm space group. TGA analyses shows that the materials is going to decrease by 0.32%. The density of the materials was calculated from structural refinement and found to be 8.372 gm/cm3.

  12. Infrared reflectivity investigation of the phase transition sequence in Pr0.5Ca0.5MnO3

    NASA Astrophysics Data System (ADS)

    Ribeiro, J. L.; Vieira, L. G.; Gomes, I. T.; Araújo, J. P.; Tavares, P.; Almeida, B. G.

    2016-06-01

    This work reports an infrared reflectivity study of the phase transition sequence observed in Pr0.5Ca0.5MnO3. The need to measure over an extended spectral range in order to properly take into account the effects of the high frequency polaronic absorption is circumvented by adopting a simple approximate method, based on the asymmetry present in the Kramers Kronig inversion of the phonon spectrum. The temperature dependence of the phonon optical conductivity is then investigated by monitoring the behavior of three relevant spectral moments of the optical conductivity. This combined methodology allows us to disclose subtle effects of the orbital, charge and magnetic orders on the lattice dynamics of the compound. The characteristic transition temperatures inferred from the spectroscopic measurements are compared and correlated with those obtained from the temperature dependence of the induced magnetization and electrical resistivity.

  13. Direct band gap optical emission from compressively strained Ge films grown on relaxed Si{sub 0.5}Ge{sub 0.5} substrate

    SciTech Connect

    Aluguri, R.; Manna, S.; Ray, S. K.

    2013-10-14

    Compressively strained Ge films have been grown on relaxed Si{sub 0.5}Ge{sub 0.5} virtual substrate in ultra high vacuum using molecular beam epitaxy. Structural characterization has shown that the Ge films are compressively strained with partial strain relaxation in a film thicker than 3.0 nm, due to onset of island nucleation. Photoluminescence spectra exhibit the splitting of degenerate Ge valence band into heavy hole and light hole bands with a broad direct band gap emission peak around 0.81 eV. Temperature and excitation power dependent emission characteristics have been studied to investigate the mechanism of luminescence quenching at high temperatures and the role of non-radiative recombination centers.

  14. Dielectric Properties of SrMnO3-doped K0.5Na0.5NbO3 Lead-Free Ceramics

    NASA Astrophysics Data System (ADS)

    Deng, Jianming; Sun, Xiaojun; Liu, Laijun; Liu, Saisai; Huang, Yanmin; Fang, Liang; Elouadi, Brahim

    2016-08-01

    (1- x)K0.5Na0.5NbO3- xSrMnO3 (0.02 ≤ x ≤ 0.08) (KNN- xSM) ceramics were fabricated by a conventional solid-state technique. X-ray diffraction of the samples revealed that the crystal structure changes from orthorhombic to tetragonal, and finally to pseudocubic symmetry with increasing x. Temperature dependence of dielectric properties showed that the temperature ( T m) corresponding to the maximum of dielectric permittivity decreased with increasing x. Two dielectric relaxation processes occurred at high temperatures, which were attributed to grain and grain boundary responses, respectively. Polarization hysteresis loops ( P- E) at different electrical fields were displayed. P rmax degenerated with the increase of SM due to the thermally activated leakage current increases. The relationship between electrical properties and defect compensation mechanism is discussed.

  15. Possible surface antiferromagnetism and no evidence for intergranular tunneling magnetoresistance in La0.5Sr0.5CoO3-δ cobaltites

    NASA Astrophysics Data System (ADS)

    Troyanchuk, I. O.; Bushinsky, M. V.; Lobanovsky, L. S.

    2013-12-01

    The magnetization and magnetoresistance (MR) of La0.5Sr0.5CoO3-δ have been studied as function of surface/volume ratio and oxygen deficit. All the samples have positive and negative components of MR at low temperature. The small positive component is predominated in low field regime below and well above the coercive field. The positive MR under magnetic moment reorientation is in contradiction with scenario of negative intergranular tunneling magnetoresistance being the hallmark of half-metallic polycrystalline oxides. The oxygen deficit leads to a gradual stabilization of antiferromagnetic phase in bulk and concomitant enhancement of the MR. The decrease in value of magnetization and enhancement of the negative MR component in compacted at high pressure/room temperature powder with a large surface/volume ratio can be ascribed to antiferromagnetism at the surface.

  16. Good Quality Factor in GdMnO3-Doped (K0.5Na0.5)NbO3 Piezoelectric Ceramics

    NASA Astrophysics Data System (ADS)

    Bucur, Raul Alin; Badea, Iuliana; Bucur, Alexandra Ioana; Novaconi, Stefan

    2016-06-01

    (1 - x)(K0.5Na0.5)NbO3 - xGdMnO3 (KNN- xGM) ferroelectric ceramics (0 ≤ x ≤ 5 mol.%) were obtained through a solid state technique. For all the studied compositions, orthorhombic perovskite crystalline structures were obtained at room temperature. GdMnO3 suppresses the grain growth and gives rather homogenous microstructures as the concentration increases. The doped ceramics exhibita good dielectric response, a "hard" ferroelectric behavior and good piezoelectric properties. An improved mechanical quality factor of 1180 and a high Curie temperature T C = 400°C, coupled with k p = 0.426, makes the composition x = 1 mol.% GdMnO3 suitable for lead-free piezoelectric materials for high-power and high-temperature applications.

  17. Effect of Natural Aging and Cold Working on Microstructures and Mechanical Properties of Al-4.6Cu-0.5Mg-0.5Ag alloy

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Te; Lee, Sheng-Long; Bor, Hui-Yun; Lin, Jing-Chie

    2013-06-01

    This research investigates the effects of natural aging and cold working prior to artificial aging on microstructures and mechanical properties of Al-4.6Cu-0.5Mg-0.5Ag alloy. Mechanical properties relative to microstructure variations were elucidated by the observations of the optical microscope (OM), differential scanning calorimeter (DSC), electrical conductivity meter (pct IACS), and transmission electron microscopy (TEM). The results showed that natural aging treatment has little noticeable benefit on the quantity of precipitation strengthening phases and mechanical properties, but it increases the precipitation strengthening rate at the initial stage of artificial aging. Cold working brings more lattice defects which suppress Al-Cu (GP zone) and Mg-Ag clustering, and therefore the precipitation of Ω phase decreases. Furthermore, more dislocations are formed, leading to precipitate the more heterogeneous nucleation of θ' phase. The above-mentioned precipitation phenomena and strain hardening effect are more obvious with higher degrees of cold working.

  18. Single crystalline La0.5Sr0.5MnO3 microcubes as cathode of solid oxide fuel cell

    SciTech Connect

    Mingjia Zhi; Guangwen Zhou; Zhanglian Hong; Jin Wang; Randall Gemmen; Kirk Gerdes; Ayyakkannu Manivannan; Dongling Mae; Nianqiang Wu

    2010-09-13

    The efficiency of solid oxide fuel cells (SOFCs) is heavily dependent on the electrocatalytic activity of the cathode toward the oxygen reduction reaction (ORR). In order to achieve better cathode performance, single crystalline La0.5Sr0.5MnO3 (LSM) microcubes with the {200} facets have been synthesized by the hydrothermal method. It is found that the LSM microcubes exhibit lower polarization resistance than the conventional polycrystalline La0.8Sr0.2MnO3 powder in air from 700 #2;C to 900 #2;C. The ORR activation energy of the LSM microcubes is lower than that of the conventional powder. The ORR kinetics for the microcubes is limited by the charge transfer step while that for the conventional powder is dominated by the oxygen adsorption and dissociation on the cathode surface.

  19. Flux Pinning by Cr Nanoparticles in Cu_{0.5}Tl_{0.5}Ba2Ca2Cu3O_{10-δ } Superconductor

    NASA Astrophysics Data System (ADS)

    Waqee-ur-Rehman, M.; Mumtaz, M.; Qasim, Irfan; Nadeem, K.

    2016-09-01

    Increase in flux pinning strength of Cu_{0.5}Tl_{0.5}Ba2Ca2Cu3O_{10-δ }(CuTl-1223) superconductor has been observed after addition of Cr nanoparticles. We have thoroughly investigated the infield response of Cr nanoparticles-added CuTl-1223 superconductor in an external applied magnetic field in the range of 0-7 T. Solid-state reaction technique has been employed to synthesize (Cr)x-CuTl-1223; x = 0-1.00 wt% nanoparticle-superconductor composites. The flux pinning mechanism has been analyzed on the basis of thermally activated flux flow model in the presence of a small current (10 μ A). The increase in activation energy and decrease in transition width of CuTl-1223 superconducting phase show the enhancement in its flux pinning strength upon the addition of Cr nanoparticles.

  20. Strong room temperature magnetism in highly resistive strained thin films of BiFe0.5Mn0.5O3

    NASA Astrophysics Data System (ADS)

    Choi, E.-M.; Patnaik, S.; Weal, E.; Sahonta, S.-L.; Wang, H.; Bi, Z.; Xiong, J.; Blamire, M. G.; Jia, Q. X.; MacManus-Driscoll, J. L.

    2011-01-01

    We report highly resistive strongly ferromagnetic strained thin (˜30 nm) films of BiFe0.5Mn0.5O3 (BFMO) grown on (001) SrTiO3 substrates using pulsed laser deposition. The films are tetragonal with high epitaxial quality and phase-purity. The magnetic moment and coercivity values at room temperature are 90 emu/cc (0.58μB/B-site ion) at H =3 kOe and 274 Oe, respectively. The magnetic transition temperature is strongly enhanced up to ˜600 K, which is ˜500 K higher than for pure bulk BiMnO3. Strained BFMO is a potential room temperature spin filter material for magnetic tunnel devices.

  1. Optical spectra of LaMn0.5Ga0.5O3: A contribution to the assignment of the electronic transitions in manganites

    NASA Astrophysics Data System (ADS)

    Nucara, A.; Miletto Granozio, F.; Mohamed, W. S.; Vecchione, A.; Fittipaldi, R.; Perna, P. P.; Radovic, M.; Vitucci, F. M.; Calvani, P.

    2014-01-01

    We have prepared a LaMn0.5Ga0.5O3 thin film deposited by Pulsed Laser Deposition on a LSAT substrate and we have measured its transmittance in the visible and near UV range, from 300 to 10 K. The aim was to shed light on the origin of the electronic bands in the LMO family through a comparison with the corresponding spectra collected previously on the parent compound. Two out of the four bands detected have been assigned to the intersite d-d transitions between Mn+3 ions. The other ones were ascribed to the p-d Mn-O charge-transfer transitions. We are thus led to a “mixed” interpretation where both a Mott-Hubbard and a charge-transfer approach concur to interpret the electronic spectrum of those manganites.

  2. Room-Temperature Magnetocapacitance in Fe-Doped K0.5Na0.5Nb0.95Ta0.05O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Li, Huan; Yang, Wenlong; Li, Yu; Meng, Qingxin; Zhou, Zhongxiang

    2012-10-01

    Ferroelectric and magnetic properties of Fe-doped potassium-sodium tantalate niobate (K0.5Na0.5(Nb0.95Ta0.05)1-xFexO3-x; x = 0 and 0.01) ceramics prepared by the conventional sintering method were investigated. In comparison with pure ceramics, the 0.01 Fe-doped ceramics show magnetic and ferroelectric properties simultaneously at room temperature. The relative dielectric constant significantly decreases after applying a magnetic field for the Fe-doped ceramics, indicating the coupling between ferroelectric and ferromagnetic orders. Magnetocapacitance of -0.77% was observed at room temperature and 50 kHz by the application of a magnetic field of 5000 Oe.

  3. Scintillation properties of Li6Y0.5Gd0.5(BO3)3: Ce3+ single crystal

    NASA Astrophysics Data System (ADS)

    Fawad, U.; Rooh, Gul; Kim, H. J.; Park, H.; Kim, Sunghwan; Khan, Sajid

    2015-01-01

    The Ce3+ doped mixed crystals of Li6Y(BO3)3 and Li6Gd(BO3)3 are grown by Czochralski technique with equal mole ratios of both Yttrium and Gadolinium i.e. Li6Y0.5Gd0.5(BO3)3. The grown crystals have the dimensions of ∅10×30 mm2. Powder X-ray diffraction (XRD) analysis confirmed single phase of the grown crystals. X-ray and laser induced luminescence spectra are presented. Scintillation properties such as energy resolution, light yield, decay time and α/β ratio under the excitation of 137Cs γ-ray photons and 241Am α-particles are also reported in this article.

  4. Magneto-optical spectra and electron structure of Nd0.5Gd0.5Fe3(BO3)4 single crystal

    NASA Astrophysics Data System (ADS)

    Malakhovskii, A. V.; Gnatchenko, S. L.; Kachur, I. S.; Piryatinskaya, V. G.; Sukhachev, A. L.; Temerov, V. L.

    2016-03-01

    Polarized absorption spectra and magnetic circular dichroism (MCD) spectra of Nd0.5Gd0.5Fe3(BO3)4 single crystal were measured in the range of 10000-21000 cm-1 and at temperatures 2-300 K. On the basis of these data, in the paramagnetic state of the crystal, the 4f states of the Nd3+ ion were identified in terms of the irreducible representations and in terms of | J , ± MJ > wave functions of the free atom. The changes of the Landé factor during f-f transitions were found theoretically in the | J , ± MJ > wave functions approximation and were determined experimentally with the help of the measured MCD spectra. In the majority of cases the experimentally found values are close to the theoretically predicted ones.

  5. Hierarchical mesoporous perovskite La0.5Sr0.5CoO2.91 nanowires with ultrahigh capacity for Li-air batteries

    PubMed Central

    Zhao, Yunlong; Xu, Lin; Mai, Liqiang; Han, Chunhua; An, Qinyou; Xu, Xu; Liu, Xue; Zhang, Qingjie

    2012-01-01

    Lithium-air batteries have captured worldwide attention due to their highest energy density among the chemical batteries. To provide continuous oxygen channels, here, we synthesized hierarchical mesoporous perovskite La0.5Sr0.5CoO2.91 (LSCO) nanowires. We tested the intrinsic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity in both aqueous electrolytes and nonaqueous electrolytes via rotating disk electrode (RDE) measurements and demonstrated that the hierarchical mesoporous LSCO nanowires are high-performance catalysts for the ORR with low peak-up potential and high limiting diffusion current. Furthermore, we fabricated Li-air batteries on the basis of hierarchical mesoporous LSCO nanowires and nonaqueous electrolytes, which exhibited ultrahigh capacity, ca. over 11,000 mAh⋅g –1, one order of magnitude higher than that of LSCO nanoparticles. Besides, the possible reaction mechanism is proposed to explain the catalytic activity of the LSCO mesoporous nanowire. PMID:23150570

  6. Hierarchical mesoporous perovskite La0.5Sr0.5CoO2.91 nanowires with ultrahigh capacity for Li-air batteries.

    PubMed

    Zhao, Yunlong; Xu, Lin; Mai, Liqiang; Han, Chunhua; An, Qinyou; Xu, Xu; Liu, Xue; Zhang, Qingjie

    2012-11-27

    Lithium-air batteries have captured worldwide attention due to their highest energy density among the chemical batteries. To provide continuous oxygen channels, here, we synthesized hierarchical mesoporous perovskite La(0.5)Sr(0.5)CoO(2.91) (LSCO) nanowires. We tested the intrinsic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity in both aqueous electrolytes and nonaqueous electrolytes via rotating disk electrode (RDE) measurements and demonstrated that the hierarchical mesoporous LSCO nanowires are high-performance catalysts for the ORR with low peak-up potential and high limiting diffusion current. Furthermore, we fabricated Li-air batteries on the basis of hierarchical mesoporous LSCO nanowires and nonaqueous electrolytes, which exhibited ultrahigh capacity, ca. over 11,000 mAh⋅g(-1), one order of magnitude higher than that of LSCO nanoparticles. Besides, the possible reaction mechanism is proposed to explain the catalytic activity of the LSCO mesoporous nanowire. PMID:23150570

  7. Anomalous field-induced magnetoresistance behavior in Pr0.5Sr0.5MnO3 at low temperatures

    NASA Astrophysics Data System (ADS)

    Kumar, Dhirendra; Shahee, Aga; Rawat, Rajeev; Lalla, N. P.

    2012-06-01

    Low-temperature (LT) XRD and magnetoresistance (MR) have been studied in the single phase polycrystalline Pr0.5Sr0.5MnO3 with space-group I4/mcm. The resistance-vs-temperature (R-T) variation at zero-field show a broad paramagnetic to ferromagnetic metallic (FMM) transition at Tc ˜ 240K and it further undergoes FMM to antiferromagnetic insulating (AFMI) transition at TN ˜ 90K with a broad hysteresis indicates a disorder broadened first order phase transition (FOPT). The zero-field cooled (ZFC) MR at 5K shows an open loop with virgin curve lying outside the envelope curve. This anomalous behavior vanishes with increasing temperature. This has been attributed to field-induced transformation of AFMI to FMM phase, which remains arrested down to zero magnetic field at 5K.

  8. Effect of vanadium doping on structural, magnetic and magnetocaloric properties of La0.5Ca0.5MnO3

    NASA Astrophysics Data System (ADS)

    Mansouri, M.; Omrani, H.; Cheikhrouhou-Koubaa, W.; Koubaa, M.; Madouri, A.; Cheikhrouhou, A.

    2016-03-01

    We report the effect of vanadium doping on structural, magnetic and magnetocaloric properties of La0.5Ca0.5Mn1-xVxO3 (x=0.05; 0.1). Our samples were elaborated using the conventional solid state reaction method at high temperatures. X-Ray powder diffraction at room temperature indicates that our samples crystallize in the orthorhombic structure with Pbnm space group. Magnetic measurements reveal a paramagnetic-ferromagnetic transition with decreasing temperature. Magnetocaloric studies show that the maximum of the magnetic entropy change and the relative cooling power (RCP) are found to be 2.42 J Kg-1 K-1 and 162.75 J Kg-1 for x=0.05 and 3.12 J Kg-1 K-1 and 221.31 J Kg-1 for x=0.1 under a field change of 5 T.

  9. Thickness-dependent cation order and disorder in PbSc0.5Ta0.5O3 thin films grown by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Chopra, Anuj; Birajdar, Balaji I.; Berger, Andreas; Alexe, Marin; Hesse, Dietrich

    2014-01-01

    We report on thickness-dependent cation ordering and ferroelectric properties of (001)-oriented epitaxial PbSc0.5Ta0.5O3 (PST) thin films grown by pulsed laser deposition on SrTiO3 (001) and Si (001) substrates. The PST film thickness was varied from 30 to 200 nm. Only films thicker than 40 nm reveal (partial) cation ordering, which increases with thickness as confirmed by the appearance and intensity of superstructure reflections in x-ray diffraction and transmission electron microscopy. In accordance with the two-state thermodynamic model, temperature-dependent dielectric constant investigations showed the presence of two kinds of phase transitions belonging to the normal ferroelectric and the relaxor state, respectively, both being present in the PST films. The influence of cation ordering on the phase transition and ferroelectric properties is discussed in detail.

  10. Antiferromagnetic resonance in charge ordering state of Pr 0.5Ca 0.5MnO 3- δ single crystal

    NASA Astrophysics Data System (ADS)

    Kawamata, S.; Noguchi, S.; Okuda, K.; Nojiri, H.; Motokawa, M.

    2001-05-01

    An antiferromagnetic resonance (AFMR) is observed in the charge ordered antiferromagnetic phase of Pr 0.5Ca 0.5MnO 3- δ single crystal for the first time. Above the Néel temperature, TN=173 K, a paramagnetic resonance with g=2.0 is observed. There is no significant change of the resonance spectra at the charge ordering transition temperature, TCO=242 K. Below TN, a branch of AFMR is found. Since the resonance field of this mode increases linearly as the frequency is decreased, this branch is assigned as the spin-flop mode. Below 60 K, the critical fields, BC, evaluated as the extrapolation of this mode to zero frequency agree well with the insulator-metal transition fields, BCO, at which the melting of the charge-ordering phase occurs. Present results indicate that the temperature dependence of BCO is affected by the temperature dependence of BC.

  11. Microstructures and superconducting properties of single domain (Sm 0.5,Eu 0.5)Ba 2Cu 3O 7- δ superconductors fabricated in air

    NASA Astrophysics Data System (ADS)

    Hu, A.; Sakai, N.; Ogasawara, K.; Murakami, M.

    2002-01-01

    Single-domain (Sm 0.5,Eu 0.5)Ba 2Cu 3O 7- δ grains were obtained via modified melt processing in air using NdBa 2Cu 3O 7- δ seeds. The facet growth front was observed in the a/b growth direction and the stepwise growth front in the c growth direction. A series of crystal defects: dislocations, twin boundaries and local chemical variations between rare earth and Ba were revealed by transmission electron microscopy and energy dispersive spectrum analysis. In addition, a slightly higher concentration of Sm than Eu was revealed in the matrix. A high Tc value up to 94.5 K and enhanced Jc values over a wide field range at 77 K were obtained after Ar post-annealing. A pellet of diameter 16 mm trapped 0.45 T field at 77 K.

  12. Microwave dielectric and optical properties of amorphous and crystalline Ba0.5Sr0.5TiO3 thin films

    NASA Astrophysics Data System (ADS)

    Goud, J. Pundareekam; Joseph, Andrews; Ramakanth, S.; Naidu, Kuna Lakshun; Raju, K. C. James

    2016-05-01

    The thin films of composition Ba0.5Sr0.5TiO3 (BST5) were deposited by Pulsed Laser Deposition technique on amorphous fused silica substrates at room temperature (RT) and at 700°C. The film deposited at RT is amorphous while the other crystallized in cubic structure. The refractive index (n) and optical band gap (Eg) extracted from transmission spectra in the 190 -2500 nm range. Microwave dielectric properties were investigated using the Split Post Dielectric Resonators (SPDR) technique at spot frequencies of 10GHz and 20GHz. The experimental results show that thin films deposited at high temperature (700°C) shows very high dielectric constant for both 10GHz and 20 GHz. These high dielectric constant films can be used in a wide range of applications such as capacitors, non-volatile high speed random access memories, and electro-optic devices.

  13. Direct band gap optical emission from Ge islands grown on relaxed Si{sub 0.5}Ge{sub 0.5}/Si (100) substrate

    SciTech Connect

    Aluguri, R.; Manna, S.; Ray, S. K.

    2014-01-07

    Strained Ge islands have been grown on fully relaxed Si{sub 0.5}Ge{sub 0.5} substrate by pulsed laser ablation technique. The formation of strained Ge islands has been found for film with higher thickness following Stranski–Krastanov growth mechanism. The variation of strain with changing Ge layer thickness has been analyzed using Raman spectroscopy and high-resolution X-ray diffraction techniques. X-ray photoelectron spectra have shown the absence of any Si-Ge intermixing and oxidation of Ge films. A strong no-phonon photoluminescence emission from Ge islands has been observed, showing the superior optical characteristics of the islands grown on relaxed substrate.

  14. Spin-reorientation and weak ferromagnetism in antiferromagnetic TbMn{sub 0.5}Fe{sub 0.5}O{sub 3}

    SciTech Connect

    Nhalil, Hariharan E-mail: hariharan.nhalil@gmail.com; Sanathkumar, R.; Elizabeth, Suja; Nair, Harikrishnan S.; Strydom, André M.

    2015-05-07

    Orthorhombic single crystals of TbMn{sub 0.5}Fe{sub 0.5}O{sub 3} are found to exhibit spin-reorientation, magnetization reversal, and weak ferromagnetism. Strong anisotropy effects are evident in the temperature dependent magnetization measurements along the three crystallographic axes a, b, and c. A broad magnetic transition is visible at T{sub N}{sup Fe/Mn}=286 K due to paramagnetic to A{sub x}G{sub y}C{sub z} ordering. A sharp transition is observed at T{sub SR}{sup Fe/Mn}=28 K, which is pronounced along c axis in the form of a sharp jump in magnetization where the spins reorient to G{sub x}A{sub y}F{sub z} configuration. The negative magnetization observed below T{sub SR}{sup Fe/Mn} along c axis is explained in terms of domain wall pinning. A component of weak ferromagnetism is observed in field-scans along c-axis but below 28 K. Field-induced steps-like transitions are observed in hysteresis measurement along b axis below 28 K. It is noted that no sign of Tb-order is discernible down to 2 K. TbMn{sub 0.5}Fe{sub 0.5}O{sub 3} could be highlighted as a potential candidate to evaluate its magneto-dielectric effects across the magnetic transitions.

  15. Analysis of conductivity and dielectric spectra of Mn0.5Zn0.5Fe2O4 with coupled Cole-Cole type anomalous relaxations

    NASA Astrophysics Data System (ADS)

    Kumar, N. S. K.; Shahid, T. S.; Govindaraj, G.

    2016-05-01

    Most of the crystalline materials seldom show a well-defined dielectric loss peak due to domination of dc conductivity contribution, but effects of loss peaks are seen at high frequencies. Ac electrical data of nano-crystalline Mn0.5Zn0.5Fe2O4 synthesised by chemical co-precipitation method show such behaviour. Properly combined and formulated conduction and dielectric relaxation functions are required for such materials. Cole-Cole type relaxation function in the combined conduction and dielectric process is formulated for complex resistivity ρ*(ω), complex permittivity ε*(ω), complex conductivity σ*(ω) and complex electric modulus M*(ω). Conduction and dielectric relaxation are linked to Jonscher's idea of 'pinned dipole' and 'free dipole' to understand the relaxation dynamics. The physical parameters of 'pinned dipole' and 'free dipole' formalism are unique for all representations like ρ*(ω), ε*(ω), σ*(ω) and M*(ω). 'Pinned dipole' relaxation time τc related to conduction process and 'free dipole' relaxation time τd related to dielectric process show Arrhenius behaviour with the same activation energy. Correlation of dc conductivity σc with τc and τd indicates the coupled dynamics of 'pinned dipole' and 'free dipole'. Time-temperature scaling of conduction and dielectric relaxation reveals that the mechanism of coupled dynamics of 'pinned dipole' and 'free dipole' is temperature independent. Hopping of charge carriers with dynamics of disordered cation distribution of host matrix generates a coupled conduction and dielectric relaxation in Mn0.5Zn0.5Fe2O4.

  16. Ultrasonic transducers based on undoped lead-free (K0.5Na0.5)NbO3 ceramics.

    PubMed

    Bah, Micka; Giovannelli, Fabien; Schoenstein, Frederic; Brosseau, Christophe; Deschamps, Jean-Robert; Dorvaux, Frédéric; Haumesser, Lionel; Le Clezio, Emmanuel; Monot-Laffez, Isabelle

    2015-12-01

    Lead zirconate titanate (PZT) ceramics are the dominant piezoelectric elements for non-destructive evaluation (NDE) and ultrasonic transducers devices. However, the presence of lead content may impose the scientific community to develop lead-free ceramics, concerning human health and environmental safety. During the past ten years, many contributions have highlighted the potential properties of complex compositions like LiNbO3, LiTaO3 and LiSbO3 in the lead-free (K0.5Na0.5)NbO3 KNN system. In this context, for the first time, the practical applications and the effectiveness of simply undoped (K0.5Na0.5)NbO3 (KNN) ceramics are investigated. KNN powder is prepared by conventional solid state mixed oxide route. Ceramics of this material are prepared using conventional sintering (CS) and spark plasma sintering (SPS). Thickness coupling factor kt of 44-46%, planar coupling factor kp of 29-45%, relative permittivity at constant strain ε33,r(S) of 125-243 and acoustic impedance Z of 23-30 MRay are obtained for these two kinds of undoped KNN ceramics. Both ceramics are used to build single-element ultrasonic transducers. Relative bandwidth of 49-78% and insertion loss of -27 and -51dB are obtained for SPS and CS transducers, respectively. These results are suitable for use in non-destructive evaluation. The effectiveness of undoped KNN is evaluated using the KLM model, and compared to standard PZT based probe. Finally, chemical aging test of undoped KNN has demonstrated its stability in water. PMID:26117145

  17. Li(V0.5Ti0.5)S2 as a 1 V lithium intercalation electrode

    PubMed Central

    Clark, Steve J.; Wang, Da; Armstrong, A. Robert; Bruce, Peter G.

    2016-01-01

    Graphite, the dominant anode in rechargeable lithium batteries, operates at ∼0.1 V versus Li+/Li and can result in lithium plating on the graphite surface, raising safety concerns. Titanates, for example, Li4Ti5O12, intercalate lithium at∼1.6 V versus Li+/Li, avoiding problematic lithium plating at the expense of reduced cell voltage. There is interest in 1 V anodes, as this voltage is sufficiently high to avoid lithium plating while not significantly reducing cell potential. The sulfides, LiVS2 and LiTiS2, have been investigated as possible 1 V intercalation electrodes but suffer from capacity fading, large 1st cycle irreversible capacity or polarization. Here we report that the 50/50 solid solution, Li1+x(V0.5Ti0.5)S2, delivers a reversible capacity to store charge of 220 mAhg−1 (at 0.9 V), 99% of theoretical, at a rate of C/2, retaining 205 mAhg−1 at C-rate (92% of theoretical). Rate capability is excellent with 200 mAhg−1 at 3C. C-rate is discharge in 1 h. Polarization is low, 100 mV at C/2. To the best of our knowledge, the properties/performances of Li(V0.5Ti0.5)S2 exceed all previous 1 V electrodes. PMID:26996753

  18. Enhanced tunable characteristics of the Na0.5Bi0.5TiO3-NaTaO3 relaxor-type system.

    PubMed

    Spreitzer, Matjaz; König, Jakob; Jancar, Bostjan; Suvorov, Danilo

    2007-12-01

    We have investigated the voltage-tunable characteristics of the Na(0.5)Bi(0.5)TiO(3)-NaTaO(3) homogeneity region, for which samples were prepared using a conventional solid-state reaction. The highest value of the relative tunability (n(r)) was obtained for the sample with 5 mol% of NaTaO(3), i.e., 47% at 1 MHz and a 70 kV/cm dc bias field. This sample also showed the highest value of the dielectric losses (tan delta) and temperature coefficient of the dielectric constant (tau(epsilon)), i.e., 0.05 and 4478 ppm/K, respectively. As the concentration of NaTaO(3) increased up to 90 mol% n(r), tan delta, and tau(epsilon) gradually decreased toward 22%, 0.0002 and -899 ppm/K, respectively. The dielectric constant of the samples varied in a similar manner between 662 and 130. At microwave frequencies, the dielectric losses of the samples substantially increased due to their relaxor-type nature. The lowest value was obtained for the samples with 90 mol% of NaTaO(3), i.e., 0.002. The tunable characteristics of the samples are related to the ferroelectric and dielectric properties, and it appears that the dielectric tunability of the Na(0.5)Bi(0.5)TiO(3)-NaTaO(3) system originates from its relaxor-type behavior. PMID:18276566

  19. Colossal thermoelectric power in charge ordered lanthanum calcium manganites (La0.5Ca0.5MnO3)

    NASA Astrophysics Data System (ADS)

    Joy, Lija K.; Shanmukharao Samatham, S.; Thomas, Senoy; Ganesan, V.; Al-Harthi, Salim; Liebig, A.; Albrecht, M.; Anantharaman, M. R.

    2014-12-01

    Lanthanum calcium manganites (La0.5Ca0.5MnO3) with a composition close to charge ordering, synthesized by high energy ball milling, was found to exhibit colossal thermoelectric power. Thermoelectric power (TEP) data was systematically analyzed by dividing the entire temperature range (5 K-300 K) into three different regimes to explore different scattering mechanisms involved. Mandal's model has been applied to explain TEP data in the region below the Curie temperature (TC). It has been found that the variation of thermoelectric power with temperature is pronounced when the system enters the charge ordered region at T < 200 K. For temperatures lower than 120 K, due to the co-existence of charge ordered state with a spin-glass state, the variation of thermoelectric power is maximum and exhibited a peak value of -80 mV/K at 58 K. This has been explained by incorporating Kondo properties of the spin-glass along with magnon scattering. FC-ZFC magnetization measurements indicate the existence of a glassy state in the region corresponding to a maximum value of thermoelectric power. Phonon drag contribution instead of spin-glass contribution is taken into account to explain TEP in the region 120 K < T < TC. Mott's polaronic contribution of charge carriers are considered to interpret TEP in the high temperature region (T > TC). The optimal Mn4+-Mn3+ concentration in charge ordered La0.5Ca0.5MnO3 was examined by X-ray Photoelectron Spectroscopy analysis which confirms the charge ordered nature of this compound.

  20. Colossal thermoelectric power in charge ordered lanthanum calcium manganites (La{sub 0.5}Ca{sub 0.5}MnO{sub 3})

    SciTech Connect

    Joy, Lija K.; Anantharaman, M. R.; Shanmukharao Samatham, S.; Ganesan, V.; Thomas, Senoy; Al-Harthi, Salim; Liebig, A.; Albrecht, M.

    2014-12-07

    Lanthanum calcium manganites (La{sub 0.5}Ca{sub 0.5}MnO{sub 3}) with a composition close to charge ordering, synthesized by high energy ball milling, was found to exhibit colossal thermoelectric power. Thermoelectric power (TEP) data was systematically analyzed by dividing the entire temperature range (5 K–300 K) into three different regimes to explore different scattering mechanisms involved. Mandal's model has been applied to explain TEP data in the region below the Curie temperature (T{sub C}). It has been found that the variation of thermoelectric power with temperature is pronounced when the system enters the charge ordered region at T < 200 K. For temperatures lower than 120 K, due to the co-existence of charge ordered state with a spin-glass state, the variation of thermoelectric power is maximum and exhibited a peak value of −80 mV/K at 58 K. This has been explained by incorporating Kondo properties of the spin-glass along with magnon scattering. FC-ZFC magnetization measurements indicate the existence of a glassy state in the region corresponding to a maximum value of thermoelectric power. Phonon drag contribution instead of spin-glass contribution is taken into account to explain TEP in the region 120 K < T < T{sub C}. Mott's polaronic contribution of charge carriers are considered to interpret TEP in the high temperature region (T > T{sub C}). The optimal Mn{sup 4+}-Mn{sup 3+} concentration in charge ordered La{sub 0.5}Ca{sub 0.5}MnO{sub 3} was examined by X-ray Photoelectron Spectroscopy analysis which confirms the charge ordered nature of this compound.