Charge fluctuation in Ce-based filled-skutterudite

International Nuclear Information System (INIS)

Yogi, M; Niki, H; Mukuda, H; Kitaoka, Y; Sugawara, H; Sato, H

2009-01-01

We carried out 121,123 Sb nuclear quadrupole resonance (NQR) measurement on CeOs 4 Sb 12 to investigate an anomaly observed in ReOs 4 Sb 12 . The full width of half maximum of the NQR spectrum shows a step-like increase at 115 K with decreasing temperature (T). The nuclear spin-spin relaxation rate 1/T 2 also shows a divergence at the same T. These results are considered to be caused by a distribution of the electric field gradient (EFG) and its fluctuation, which might arise from a small deformation of the cage which consists of twelve Sb. It is considered that the anomaly observed in ReOs 4 Sb 12 at T ∼ 120 K is originated from an unique crystal structure of the filled skutterudite.

Electronic band structure, magnetic, transport and thermodynamic properties of In-filled skutterudites InxCo4Sb12

International Nuclear Information System (INIS)

Leszczynski, J; Da Ros, V; Lenoir, B; Dauscher, A; Candolfi, C; Masschelein, P; Hejtmanek, J; Kutorasinski, K; Tobola, J; Smith, R I; Stiewe, C; Müller, E

2013-01-01

The thermoelectric and thermodynamic properties of polycrystalline In x Co 4 Sb 12 (0.0 ⩽ x ⩽ 0.26) skutterudites were investigated and analysed between 2 and 800 K by means of electrical resistivity, thermopower, thermal conductivity and specific heat measurements. Hall effect, sound velocity and thermal expansion measurements were also made in order to gain insights into the transport and elastic properties of these compounds. The impact of the In filling on the crystal structure as well as the thermal dynamics of the In atoms were tracked down to 4 K using powder neutron diffraction experiments. Analyses of the transport data were compared with the evolution of the electronic band structure with x determined theoretically within the Korringa–Kohn–Rostoker method with the coherent potential approximation. These calculations indicate that In gives rise to a remarkably large p-like density of states located at the conduction band edge. The electrical properties show typical trends of heavily doped semiconductors regardless of the In content. The thermal transport in CoSb 3 is strongly influenced by the presence of In in the voids of the crystal structure resulting in a drop in the lattice thermal conductivity values in the whole temperature range. The low value of the Grüneisen parameter suggests that this decrease mainly originates from enhanced mass-fluctuations and point-defect scattering mechanisms. The highest thermoelectric figure of merit ZT ∼ 1.0 at 750 K was achieved at the maximum In filling fraction, i.e. for x = 0.26. (paper)

Uniaxial Pressure Effect on the SdH Oscillations in Heavy-Fermion Semimetal CeRu4Sb12

International Nuclear Information System (INIS)

Saha, S. R.; Kobayashi, M.; Sugawara, H.; Namiki, T.; Abe, K.; Aoki, Y.; Sato, H.

2003-01-01

We report the first successful Shubnikov-de Haas (SdH) experiment under uniaxial pressure in the anomalous heavy-fermion semimetal CeRu 4 Sb 12 . The nature of the quantum oscillations in the magnetoresistance is found to be significantly sensitive to uniaxial pressure. The results reveal that the nearly spherical Fermi surface elongates along the direction of the uniaxial pressure. (author)

The filled skutterudite PrOs4Sb12: superconductivity and correlations

International Nuclear Information System (INIS)

Measson, M.A.

2005-12-01

The filled skutterudite PrOs 4 Sb 12 is the first Pr-based heavy fermion superconductor. This thesis addresses several important open questions including the determination of the quasi-particle mass renormalisation, the nature and mechanism of superconductivity, and the intrinsic or extrinsic nature of the double superconducting transition seen in the specific heat. A fit of the specific heat with magnetic interactions between the ions Pr is proposed. We extract from it an electronic term of between 300-750 mJ/K 2 .mol(Pr). Analysis of the specific heat jump provides evidence that heavy carriers are involved in Cooper pairing and that superconductivity is strongly coupled. Extensive characterizations by specific heat, resistivity, susceptibility measurements show that a double transition appears in the best samples. Nevertheless we bring the first serious doubts on the intrinsic nature of the double transition, because we have found samples with a single sharp transition at Tc2 and because the ratio of the two specific heat jumps shows strong dispersion among the samples. Furthermore we have measured the superconducting phase diagrams with an A.C. specific heat technique under magnetic field and under pressure up to 4.2 GPa, and we show that the two transitions, Tc1 and Tc2, exhibit similar behaviours with magnetic field and pressure. We find a strong change in the pressure dependence of Tc's above 2 GPa which might be related to a change in the nature of the superconductivity under pressure (at least partially mediated by fluctuations and only by phonons at respectively low and high pressure) which may be linked to the increase of the crystal field gap of the Pr ions. Analysis of the upper critical field shows the presence of at least two superconducting bands and concludes to a singlet nature of the pairing. A strong distortion of the flux-line lattice, which is constant with temperature and field, is obtained by small angle neutron scattering measurement

“Pesting”-like oxidation phenomenon of p-type filled skutterudite Ce{sub 0.9}Fe{sub 3}CoSb{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Qiu, Pengfei [State Key Laboratory of High Performance Ceramic and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 DingXi Road, Shanghai 200050 (China); Xia, Xugui; Huang, Xiangyang; Gu, Ming [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 DingXi Road, Shanghai 200050 (China); Qiu, Yuting [State Key Laboratory of High Performance Ceramic and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 DingXi Road, Shanghai 200050 (China); Chen, Lidong, E-mail: chenlidong@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramic and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 DingXi Road, Shanghai 200050 (China)

2014-11-05

Highlights: • Ce{sub 0.9}Fe{sub 3}Co{sub 1}Sb{sub 12} exhibits “pesting”-like oxidation phenomenon at high temperature. • The highest oxidation rate of Ce{sub 0.9}Fe{sub 3}Co{sub 1}Sb{sub 12} appears around 800 K. • Severe periodically oxide layer peeling-off behavior is observed around 800 K. • The co-existence of Fe and Co is responsible for the poor oxidation resistance. - Abstract: Oxidation behavior of p-type filled skutterudite Ce{sub 0.9}Fe{sub 3}CoSb{sub 12} in air was investigated and the oxidation mechanism was discussed in this study. Ce{sub 0.9}Fe{sub 3}CoSb{sub 12} exhibits interesting “pesting”-like oxidation phenomenon around 800 K. The bulk sample completely disintegrates into a crowd of plate-like particles under this temperature range after only 24 h exposure in air. However, this abnormal oxidation phenomenon is not observed at temperature below 750 K or above 850 K. This result is consistent with the thermogravimetry and derivative thermogravimetry measurements which show that the oxidation rate for Ce{sub 0.9}Fe{sub 3}CoSb{sub 12} around 800 K is the highest among 650–900 K. Microstructure observations suggest that this “pesting”-like oxidation is related with the severe periodically oxide layer peeling-off behavior around 800 K, which makes the Ce{sub 0.9}Fe{sub 3}CoSb{sub 12} samples are easy to be oxidized because the fresh substrate surface is always exposed to high concentration oxygen atmosphere. X-ray diffraction and X-ray photoelectron spectroscopy measurements indicated that in the oxide scale the direct contact of Fe{sup 3+}-oxide and CoSb{sub 2}O{sub 4} which possess different formation/growth rate and volume expansion coefficient should be responsible for this peculiar oxide layer peeling-off behavior around 800 K. This work can serve as an important reference for the designation of M{sub y}Fe{sub 4−x}Co{sub x}Sb{sub 12}-based skutterudite thermoelectric device.

Specific heat of filled skutterudite PrOs4P12

International Nuclear Information System (INIS)

Matsuhira, Kazuyuki; Doi, Yoshihiro; Wakeshima, Makoto; Hinatsu, Yukio; Kihou, Kunihiro; Sekine, Chihiro; Shirotani, Ichimin

2005-01-01

We report the specific heat of filled skutterudite compounds PrOs 4 P 12 and LaOs 4 P 12 down to 1.8K. The specific heat divided by temperature C(T)/T in PrOs 4 P 12 shows a shoulder around 13K. This shoulder is caused by a Schottky anomaly due to a crystalline electric field effect. The electronic specific heat coefficients γ of PrOs 4 P 12 and LaOs 4 P 12 are estimated to be 56.5 and 21.6mJ/K 2 mol, respectively. The value of γ in PrOs 4 P 12 is 2.6 times larger than that in LaOs 4 P 12

The structure of filled skutterudites and the local vibration behavior of the filling atom

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xiaojuan [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Dongguan Institute of Neutron Science, Dongguan 523808 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zong, Peng-an [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Chen, Xihong [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Tao, Juzhou, E-mail: taoj@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Dongguan Institute of Neutron Science, Dongguan 523808 (China); Lin, He, E-mail: linhe@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201204 (China)

2017-02-15

Both of atomic pair distribution function (PDF) and extended x-ray absorption fine structure (EXAFS) experiments have been carried out on unfilled and Yb-filled skutterudites Yb{sub x}Co{sub 4}Sb{sub 12} (x=0, 0.15, 0.2 and 0.25) samples. The structure refinements on PDF data confirm the large amplitude vibration of Yb atom and the dependence of Yb vibration amplitude on the filling content. Temperature dependent EXAFS experiment on filled skutterudites have been carried out at Yb L{sub Ⅲ}-edge in order to explore the local vibration behavior of filled atom. EXAFS experiments show that the Einstein temperature of the filled atom is very low (70.9 K) which agrees with the rattling behavior.

High temperature thermoelectric properties of p-type skutterudites BaxYbyCo4-zFezSb12

KAUST Repository

Dong, Y.

2012-01-01

Several polycrystalline p-type skutterudites with compositions Ba xYb yCo 4-zFe zSb 12, with varying filler concentrations x and y, and z = 1 to 2, were synthesized by reacting the constituents and subsequent solid state annealing, followed by densification by hot-pressing. Their thermoelectric properties were evaluated from 300 to 820 K. The Yb filling fraction increased with Fe content while the amount of Fe substitution had little influence on the Ba filling fraction. High purity specimens were obtained when the Fe content was low. Bipolar conduction contributed to the thermal conductivity at elevated temperatures. A maximum ZT value of 0.7 was obtained at 750 K for the specimen with the highest Fe content and filling fraction. The potential for thermoelectric applications is also discussed. © 2012 American Institute of Physics.

Study of 5f electron based filled skutterudite compound EuFe{sub 4}Sb{sub 12}, a thermoelectric (TE) material: FP-LAPW method

Energy Technology Data Exchange (ETDEWEB)

Shankar, A., E-mail: amitshan2009@gmail.com [Department of Physics, Mizoram University, Aizawl 796004 (India); Rai, D.P., E-mail: dibyaprakashrai@gmail.com [Beijing Computational Science Research Center, 3 Heqing Road, Beijing 100084 (China); Khenata, R. [Laboratoire de Physique Quantique et de Modlisation Mathmatique (LPQ3M), Dpartement de Technologie, Universit de Mascara, 29000 Mascara (Algeria); Maibam, J. [Department of Physics, Assam University, Silchar 788011 (India); Sandeep, E-mail: sndp.chettri@gmail.com [Department of Physics, Mizoram University, Aizawl 796004 (India); Thapa, R.K., E-mail: r.k.thapa@gmail.com [Department of Physics, Mizoram University, Aizawl 796004 (India)

2015-01-15

Highlights: • The compound EuFe{sub 4}Sb{sub 12} shows a semi-metallic behavior with pseudo gap. • The inherent dense band near E{sub F} facilitate the charge carriers. • The magnetic moment within LSDA and mBJ are underestimated. • The inclusion of onsite Coulomb repulsion (U) in LSDA has improved the result. • The results obtained from LSDA + U are consistent with the experimental data. - Abstract: We have studied the elastic, electronic and magnetic properties along with the thermoelectric properties of an undoped filled skutterudite EuFe{sub 4}Sb{sub 12} using full-potential linearized augmented plane wave (FP-LAPW) method. The LSDA, LSDA + U and a new exchange-correlation functional called modified Becke Johnson (mBJ) potential based on density functional theory (DFT) were used for studying material properties. The Eu-f and Fe-d are strongly correlated elements thus the inclusion of Coulomb repulsion (U) expected to give an exact ground state properties. The exchange-splitting of Eu-4f states were analyzed to explain the ferromagnetic behavior of EuFe{sub 4}Sb{sub 12} (half-metallic behavior). The numerical values of isotropic elastic parameters and related properties are estimated in the framework of the Voigt–Reuss–Hill approximation. The calculation of thermal transport properties at various temperature shows the high value of Seebeck coefficient and figure of merit (ZT) = 0.25 at room temperature in consistent to the experimental results.

FP-LAPW calculations of the elastic, electronic and thermoelectric properties of the filled skutterudite CeRu{sub 4}Sb{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Shankar, A., E-mail: amitshan2009@gmail.com [Condensed Matter Theory Group, Department of Physics, Mizoram University, 796004 (India); Rai, D.P. [Department of Physics, Pachhunga University College, Aizawl 796001 (India); Chettri, Sandeep [Condensed Matter Theory Group, Department of Physics, Mizoram University, 796004 (India); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 (Algeria); Thapa, R.K. [Condensed Matter Theory Group, Department of Physics, Mizoram University, 796004 (India)

2016-08-15

We have investigated the electronic structure, elastic and thermoelectric properties of the filled skutterudite CeRu{sub 4}Sb{sub 12} using the density functional theory (DFT). The full potential linearized augmented plane wave (FP-LAPW) method within a framework of the generalized gradient approximation (GGA) approach is used to perform the calculations presented here. The electronic structure calculation suggests an indirect band gap semiconducting nature of the material with energy band gap of 0.08 eV. The analysis of the elastic constants at relaxed positions reveals the ductile nature of the sample material with covalent contribution in the inter-atomic bonding. The narrow band gap semiconducting nature with high value of Seebeck coefficient suggests the possibility of the thermoelectric application of the material. The analysis of the thermal transport properties confirms the result obtained from the energy band structure of the material with high thermopower and dimensionless figure of merit 0.19 at room temperature.

The filled skutterudite PrOs{sub 4}Sb{sub 12}: superconductivity and correlations; La skutterudite PrOs{sub 4}Sb{sub 12}: supraconductivite et correlations

Energy Technology Data Exchange (ETDEWEB)

Measson, M.A

2005-12-15

The filled skutterudite PrOs{sub 4}Sb{sub 12} is the first Pr-based heavy fermion superconductor. This thesis addresses several important open questions including the determination of the quasi-particle mass renormalisation, the nature and mechanism of superconductivity, and the intrinsic or extrinsic nature of the double superconducting transition seen in the specific heat. A fit of the specific heat with magnetic interactions between the ions Pr is proposed. We extract from it an electronic term of between 300-750 mJ/K{sup 2}.mol(Pr). Analysis of the specific heat jump provides evidence that heavy carriers are involved in Cooper pairing and that superconductivity is strongly coupled. Extensive characterizations by specific heat, resistivity, susceptibility measurements show that a double transition appears in the best samples. Nevertheless we bring the first serious doubts on the intrinsic nature of the double transition, because we have found samples with a single sharp transition at Tc2 and because the ratio of the two specific heat jumps shows strong dispersion among the samples. Furthermore we have measured the superconducting phase diagrams with an A.C. specific heat technique under magnetic field and under pressure up to 4.2 GPa, and we show that the two transitions, Tc1 and Tc2, exhibit similar behaviours with magnetic field and pressure. We find a strong change in the pressure dependence of Tc's above 2 GPa which might be related to a change in the nature of the superconductivity under pressure (at least partially mediated by fluctuations and only by phonons at respectively low and high pressure) which may be linked to the increase of the crystal field gap of the Pr ions. Analysis of the upper critical field shows the presence of at least two superconducting bands and concludes to a singlet nature of the pairing. A strong distortion of the flux-line lattice, which is constant with temperature and field, is obtained by small angle neutron scattering

Rare-earth (R) and transition metals (d) based skutterudites RM4Sb12: new materials for thermoelectric power generation; Etude de skutterudites de terres-rares (R) et de metaux d (M) du type RM4Sb12: de nouveaux materiaux thermoelectriques pour la generation d'electricite

Energy Technology Data Exchange (ETDEWEB)

Berardan, D.

2004-07-15

This thesis presents the physical and thermoelectric properties of new skutterudite compounds, with general formula R{sub y-p}R'{sub p}Fe{sub 4-x}(Co/Ni){sub x}Sb{sub 12} (R and R' = Ce, Yb, Ba, La). It shows that Yb valence state decreases when Yb fraction increases. However, it does not depend on the temperature, which evidences a mixed valence state (two different valence states for two distinct crystallographic sites at a local point of view). Ce is always trivalent in these compounds. The character of the dominant interactions changes from antiferromagnetic to ferromagnetic when one goes from trivalent cerium or lanthanum to nearly divalent ytterbium or divalent barium. The effective paramagnetic moment has been separated into three contributions originating from Ce, Yb and [Fe{sub 4}Sb{sub 12}]. The last one does not depend on the nature or on the valence state or R and R' atoms, but it decreases when Ni substitutes Fe. A magnetic transition occurs at 6.5 K for R = Yb and Ba, possibly to a spin glass state. Electrical and thermal transport properties have been determined from 5 K to 800 K, and the materials properties of the materials have been discussed concerning thermoelectric power generation. The power factor, and the thermoelectric figure of merit ZT are increased in Ce{sub y}/2Yb{sub y}/2Fe{sub 4-x}(Co/Ni){sub x}Sb{sub 12} type skutterudites as compared to R{sub y}Fe{sub 4-x}(Co/Ni){sub x}Sb{sub 12} type skutterudites. (author)

Phase stability and lattice thermal conductivity reduction in CoSb{sub 3} skutterudites, doped with chalcogen atoms

Energy Technology Data Exchange (ETDEWEB)

Battabyal, M., E-mail: manjusha.battabyal@project.arci.res.in; Priyadarshini, B.; Gopalan, R. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), IIT M Research Park, Taramani, Chennai-600113 (India); Pradipkanti, L.; Satapathy, Dillip K. [Department of Physics, Indian Institute of Technology Madras, Chennai-600036 (India)

2016-07-15

We report a significant reduction in the lattice thermal conductivity of the CoSb{sub 3} skuttertudites, doped with chalcogen atoms. Te/Se chalcogen atoms doped CoSb{sub 3} skutterudite samples (Te{sub 0.1}Co{sub 4}Sb{sub 12}, Se{sub 0.1}Co{sub 4}Sb{sub 12}, Te{sub 0.05}Se{sub 0.05}Co{sub 4}Sb{sub 12}) are processed by ball milling and spark plasma sintering. X-ray diffraction data combined with energy dispersive X-ray spectra indicate the doping of Te/Se chalcogen atoms in the skutterudite. The temperature dependent X-ray diffraction confirms the stability of the Te/Se doped CoSb{sub 3} skutterudite phase and absence of any secondary phase in the temperature range starting from 300 K to 773 K. The Raman spectroscopy reveals that different chalcogen dopant atoms cause different resonant optical vibrational modes between the dopant atom and the host CoSb{sub 3} skutterudite lattice. These optical vibrational modes do scatter heat carrying acoustic phonons in a different spectral range. It was found that among the Te/Se chalcogen atoms, Te atoms alter the host CoSb{sub 3} skutterudite lattice vibrations to a larger extent than Se atoms, and can potentially scatter more Sb related acoustic phonons. The Debye model of lattice thermal conductivity confirms that the resonant phonon scattering has important contributions to the reduction of lattice thermal conductivity in CoSb{sub 3} skutterudites doped with Te/Se chalcogen atoms. Lattice thermal conductivity ∼ 0.9 W/mK at 773 K is achieved in Te{sub 0.1}Co{sub 4}Sb{sub 12} skutterudites, which is the lowest value reported so far in CoSb{sub 3} skutterudites, doped with single Te chalcogen atom.

Thermoelectric properties of high pressure synthesized lithium and calcium double-filled CoSb3

Directory of Open Access Journals (Sweden)

Xiaohui Li

2017-01-01

Full Text Available Lithium and calcium are inefficient filling elements of CoSb3 at ambient pressure, but show nice filling behavior under high pressure. In this work, we synthesized Li/Ca double-filled CoSb3 with high pressure synthesis method. The products show the skutterudite structure of Im3¯ symmetry. Thermoelectric properties were effectively enhanced through Li and Ca co-filling. For the optimal Li0.08Ca0.18Co4Sb12 sample, the power factor maintains a relatively high value over the whole measurement temperature range and peaks at 4700μWm−1K−2, meanwhile the lattice thermal conductivity is greatly suppressed, leading to a maximal ZT of 1.18 at 700 K. Current work demonstrates high pressure synthesis as an effective method to produce multiple elemental filled CoSb3 skutterudites.

Thermoelectric properties of In{sub 0.2}Co{sub 4}Sb{sub 12} skutterudites with embedded PbTe or ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chubilleau, C.; Lenoir, B.; Candolfi, C.; Masschelein, P. [Université de Lorraine, CNRS, UMR 7198, Institut Jean Lamour, Parc de Saurupt, 54011 Nancy (France); Dauscher, A., E-mail: anne.dauscher@univ-lorraine.fr [Université de Lorraine, CNRS, UMR 7198, Institut Jean Lamour, Parc de Saurupt, 54011 Nancy (France); Guilmeau, E. [Laboratoire CRISMAT, UMR 6508, 6 boulevard Maréchal Juin, 14050 Caen Cedex (France); Godart, C. [ICMPE-CMTR, CNRS-UMR 7182, 2-8 rue H. Dunant, 94320 Thiais (France)

2014-03-15

Highlights: • Fabrication of nanostructured skutterudites ZnO or PbTe/In{sub 0.2}Co{sub 4}Sb{sub 12.} • Thermal conductivity modeling accounts for experimental results. • Greater lattice thermal conductivity decrease in In{sub 0.2}Co{sub 4}Sb{sub 12} than in CoSb{sub 3}. • A max ZT of 1.05 is obtained at 700 K in a 2 wt% ZnO-containing sample. -- Abstract: Transport properties of the skutterudite compound In{sub 0.2}Co{sub 4}Sb{sub 12} containing ZnO or PbTe nano-sized particles (2–12 wt%) were investigated by means of electrical resistivity, thermopower and thermal conductivity between 5 and 800 K. The composite powders were prepared by freeze-drying the nanoparticles with micron-sized In{sub 0.2}Co{sub 4}Sb{sub 12} powders. Densification was achieved by spark plasma sintering. All composites were characterized by X-ray powder diffraction and scanning electron microscopy. All the transport coefficients show similar temperature dependences suggesting little influence of the nature, semiconducting or insulating, of the nanoparticles. Both the electrical and the thermal conductivities decrease with increasing the PbTe or ZnO content. The impact of ZnO and PbTe on the thermal conductivity was modelled based on the Debye model taking into account a relaxation time constant reflecting phonon scattering by spherical nanoparticles. A maximum dimensionless figure of merit ZT of 1.05 at 700 K was achieved in a sample containing 2 wt% ZnO, a value quite similar to that of the reference In{sub 0.2}Co{sub 4}Sb{sub 12} compound.

High-Pressure Synthesis, Structure, and Magnetic Properties of Ge-Substituted Filled Skutterudite Compounds; LnxCo4Sb12−yGey, Ln = La, Ce, Pr, and Nd

Directory of Open Access Journals (Sweden)

Hiroshi Fukuoka

2017-12-01

Full Text Available A series of new Ge-substituted skutterudite compounds with the general composition of LnxCo4Sb12−yGey, where Ln = La, Ce, Pr, and Nd, is prepared by high-pressure and high-temperature reactions at 7 GPa and 800 °C. They have a cubic unit cell and the lattice constant for each compound is 8.9504 (3, 8.94481 (6, 8.9458 (3, and 8.9509 (4 Å for the La, Ce, Pr, and Nd derivatives, respectively. Their chemical compositions, determined by electron prove microanalysis, are La0.57Co4Sb10.1Ge2.38, Ce0.99Co4Sb9.65Ge2.51, Pr0.97Co4Sb9.52Ge2.61, and Nd0.87Co4Sb9.94Ge2.28. Their structural parameters are refined by Rietveld analysis. The guest atom size does not affect the unit cell volume. The Co–Sb/Ge distance mainly determines the unit cell size as well as the size of guest atom site. The valence state of lanthanide ions is 3+.

Improved thermoelectric performance of n-type Ca and Ca-Ce filled skutterudites

Energy Technology Data Exchange (ETDEWEB)

Thompson, Daniel R.; Liu, Chang; Ellison, Nicole D. [Optimal CAE, Plymouth, Michigan 48170 (United States); Salvador, James R.; Meyer, Martin S.; Haddad, Daad B. [General Motors Research and Development, Warren, Michigan 48090 (United States); Wang, Hsin; Cai, W. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2014-12-28

Thermoelectric (TE) technology for use in automotive waste heat recovery is being advanced by General Motors with support from the US Department of Energy. Skutterudites are a very promising material for this application of TE technology due to their superior mechanical properties and good TE performance. Double-filled Yb{sub x}Ba{sub y}Co{sub 4}Sb{sub 12} with ZT values around 1.1 at 750 K are the best performing n-type skutterudites produced on a large scale using an economically viable approach of melt spinning (MS) in conjunction with spark plasma sintering (SPS). Another economical production method on the tons scale, the melt quench annealing (MQA) technique, has been recently claimed by Treibacher Industrie AG, further information is available [G. Rogl et al., Acta Mater. 76, 434–448 (2014)]. A possible hurdle to commercial implementation of these materials is the use of rare earths as the fillers to reduce thermal conductivity and improve the electrical transport properties. It will be shown herein that skutterudites double-filled with Ca and Ce, both of which are lower-cost fillers, display markedly different TE properties depending on whether they are produced by MQA or MS + SPS synthesis techniques. Ca and Ce double-filled skutterudites prepared by MS + SPS have TE properties that are superior to the same compositions prepared by MQA and that are comparable to the best performing Yb and Ba filled materials. Furthermore, the results of this study suggest that the unusually poor transport properties of MQA Ca-filled skutterudites can be ascribed to deleterious secondary phases, which is contrary to reports in the literature attempting to explain these irregularities via band structure features.

Filled skutterudite antimonides: Validation of the electron-crystal phonon-glass approach to new thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Mandrus, D; Sales, B C; Keppens, V [and others

1997-07-01

After a brief review of the transport and thermoelectric properties of filled skutterudite antimonides, the authors present resonant ultrasound, specific heat, and inelastic neutron scattering results that establish the existence of two low-energy vibrational modes in the filled skutterudite LaFe{sub 3}CoSb{sub 12}. It is likely that at least one of these modes represents the localized, incoherent vibrations of the La ion in an oversized atomic cage. These results support the usefulness of weakly bound, rattling ions for the improvement of thermoelectric performance.

Magnetic properties of the filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 synthesized under high pressure

OpenAIRE

Sekine, C; Uchiumi, T; Shirotani, I; Matsuhira, kazuyuki; Sakakibara, T; Goto, T; Yagi, T

2000-01-01

We have succeeded in synthesizing filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 under high pressure. The magnetic properties of GdRu4P12 and TbRu4P12 have been studied by means of electrical resistivity, magnetic susceptibility, and magnetization measurements. Magnetic experiments suggest that the Gd and Tb ions in the compounds have trivalent state. The compound GdRu4P12 displays features that suggest the occurrence of antiferromagnetic ordering below TN=22 K. In TbRu4P1...

Structure and Chemical Bond of Thermoelectric Ce-Co-Sb Skutterudites

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

The correlations among composition,structure,chemical bond and thermoelectric property of skutterudites CoSb3 and CeCo5Fe3Sb12 have been studied by using density function and discrete variation (DFT-DVM) method.Three models for this study were proposed and calculated by which the "rattling" pattern was described.Model 1 is with Ce in the center,model 2 is with Ce away the center and near to Sb,and model 3 is also with Ce away the center but near to Fe.The calculated results show that in model 3,the ionic bond is the strongest,but the covalent bond is the weakest.Due to the different changes between ionic and covalent bond,there is less difference in the stability among the models 1,2 and 3.Therefore,these different models can exist at the same time,or can translate from one to another more easily.In other words,the "rattling" pattern has taken place.Unfilled model of CoSb3,without Ce and Fe,is called model 4.The covalent bond of Co-Sb or Fe-Sb in models 1,2 and 3 is weaker than that of Co-Sb in model 4,as some electrical cloud of Sb takes part in the covalent bond of Ce-Sb in the filled models.The result is consistent with the experimental result that the thermal conductivity of CeCo5Fe3Sb12 is lower than that of CoSb3,and the thermoelectric property of CeCo5Fe3Sb12 is superior to that of CoSb3.

Dependence of the superconducting transition temperature of the filled skutterudite compound PrPt{sub 4}Ge{sub 12} on hydrostatic pressure

Energy Technology Data Exchange (ETDEWEB)

Foroozani, N. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Hamlin, J.J. [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Schilling, J.S., E-mail: jss@wuphys.wustl.edu [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Baumbach, R.E.; Lum, I.K.; Shu, L.; Huang, K.; Maple, M.B. [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States)

2013-02-14

Highlights: ► Superconductivity in the filled skutterudite PrPt{sub 4}Ge{sub 12}. ► Dependence of T{sub c} on purely hydrostatic pressure to 0.6 GPa. ► Comparison of lattice pressure to external pressure effects on superconductivity. ► Evidence for magnetic pair-breaking effects. -- Abstract: The temperature-dependent ac susceptibility of the filled skutterudite superconductor PrPt{sub 4}Ge{sub 12} has been measured under hydrostatic He-gas pressure to 0.58 GPa. The superconducting transition temperature T{sub c} decreases linearly with pressure P from 7.91 K at ambient pressure to 7.83 K at 0.58 GPa, giving the rate dT{sub c}/dP = −0.19 ± 0.03 K/GPa. Evidence is presented that suggests that the value of T{sub c} in this compound is slightly reduced due to magnetic pair-breaking effects from the Pr{sup 3+} cations.

NMR study of magnetic properties in filled skutterudite compound EuRu4P12

International Nuclear Information System (INIS)

Magishi, Ko-ichi; Iwahashi, Yoshinori; Horimoto, Takuji; Sugawara, Hitoshi; Saito, Takahito; Koyama, Kuniyuki

2007-01-01

We report the results of 31 P NMR measurements on a Eu-based filled skutterudite phosphide EuRu 4 P 12 with ferromagnetic transition at T C =18K in order to investigate the magnetic properties from a microscopic point of view. The temperature dependence of the Knight shift is similar to that of the magnetic susceptibility. Also, the nuclear spin-lattice relaxation rate 1/T 1 is practically constant at higher temperatures above 50K due to the interaction of the 31 P nucleus with fluctuating local moments at the Eu 2+ sites, but decreases rapidly at low temperatures below T C , indicating the supression of the spin fluctuations by magnetic ordering

Synthesis crystal stuctrure and thermoelectric properties of the ternary skutterudite Fe2Pd2Sb12

Czech Academy of Sciences Publication Activity Database

Navrátil, Jiří; Laufek, F.; Plecháček, T.; Plášil, J.

2010-01-01

Roč. 493, 1-2 (2010), s. 50-54 ISSN 0925-8388 R&D Projects: GA ČR GA203/07/0267 Institutional research plan: CEZ:AV0Z40500505 Keywords : Fe2Pd2Sb12 * crystal structure * skutterudite Subject RIV: CA - Inorganic Chemistry Impact factor: 2.138, year: 2010

Raman scattering study of filled skutterudite compounds

International Nuclear Information System (INIS)

Ogita, N; Kojima, R; Hasegawa, T; Takasu, Y; Udagawa, M; Kondo, T; Takeda, N; Ikeno, T; Ishikawa, K; Sugawara, H; Kikuchi, D; Sato, H; Sekine, C; Shirotani, I

2007-01-01

Raman scattering of skutterudite compounds RT 4 X 12 (R=La, Ce, Pr, Nd, Sm and Yb, T=Fe, Ru and Os, X=P and Sb) have been measured. All first-order Raman active phonons are observed and are assigned as the pnicogen vibrations. At the low energy region, the second-order phonons, due to the vibration of the rare earth ions with a flat phonon dispersion, are observed in the spectra of RRu 4 P 12 (R=La and Sm) and ROs 4 Sb 12 (R=La, Ce, Pr, Nd, and Sm). The appearance of the second-order phonons in the spectra is caused by an anharmonic vibrations of rare earth ions in large cage space and a large density of state due to the flat phonon dispersion. However, in spite of the similar cage space, the 2nd-order phonons are hardly observed for RFe 4 Sb 12 and RRu 4 Sb 12 . Thus, these results suggest that the dynamics of the rare earth ion is closely related to not only the cage size but also the electronic state due to the transition metals. Raman spectra of PrRu 4 P 12 show the drastic spectral change due to the metal-insulator transition. The phonon spectra and crystal field excitations due to the structural change have been assigned above and below the transition temperature

Structure, microstructure and microhardness of rapidly solidified Smy(FexNi1-x)4Sb12 (x = 0.45, 0.50, 0.70, 1) thermoelectric compounds

Science.gov (United States)

Artini, C.; Castellero, A.; Baricco, M.; Buscaglia, M. T.; Carlini, R.

2018-05-01

Skutterudites are interesting compounds for thermoelectric applications. The main drawback in the synthesis of skutterudites by solidification of the melt is the occurrence of two peritectic reactions requiring long annealing times to form a single phase. Aim of this work is to investigate an alternative route for synthesis, based on rapid solidification by planar flow casting. The effect of cooling rate on phases formation and composition, as well as on structure, microstructure and mechanical properties of the filled Smy(FexNi1-x)4Sb12 (x = 0.45, 0.50, 0.70, 1) skutterudites was studied. Conversely to slowly cooled ingots, rapidly quenched ribbons show skutterudite as the main phase, suggesting that deep undercooling of the liquid prevents the nucleation of high temperature phases, such as (Fe,Ni)Sb and (Fe,Ni)Sb2. In as-quenched samples, a slightly out of equilibrium Sm content is revealed, which does not alter the position of the p/n boundary; nevertheless, it exerts an influence on crystallographic properties, such as the cell parameter and the shape of the Sb4 rings in the structure. As-quenched ribbons show a fine microstructure of the skutterudite phase (grain size of 2-20 μm), which only moderately coarsens after annealing at 873 K for 4 days. Vickers microhardness values (350-400 HV) of the skutterudite phase in as-quenched ribbons are affected by the presence of softer phases (i.e. Sb), which are homogeneously and finely dispersed within the sample. The skutterudite hardens after annealing as a consequence of a moderate grain growth, which limits the matrix effect due to the presence of additional phases.

High-temperature thermoelectric properties of p-type skutterudites Ba0.15Yb x Co3FeSb12 and Yb y Co3FeSb9As3

KAUST Repository

Dong, Yongkwan

2014-08-28

Two series of p-type polycrystalline skutterudites, Ba0.15YbxCo3FeSb12 and YbyCo3FeSb9As3 with varying Yb concentrations, were synthesized by solid-state reaction and then densified by hot pressing. The phase and stoichiometries of the resulting materials were characterized by powder X-ray diffraction and energy dispersive spectroscopy, while their high-temperature transport properties were investigated from 300 to 800 K. The Seebeck coefficients and electrical resistivities increased linearly with increasing temperature for the double-filled specimens. The Seebeck coefficients and electrical resistivities did not change very much for the As-substituted specimens. The thermal conductivity for all specimens decreased with increasing temperature up to 700 K, corresponding to the plateau in the Seebeck coefficient, and then increased again due to bipolar diffusion. We find that double filling is a more feasible approach to thermoelectric property optimization than single filling with As substitution. © 2014 Springer Science+Business Media New York.

Magnetic properties of Sm-based filled skutterudite phosphides

Energy Technology Data Exchange (ETDEWEB)

Giri, R.; Sekine, C.; Shimaya, Y.; Shirotani, I.; Matsuhira, K.; Doi, Y.; Hinatsu, Y.; Yokoyama, M.; Amitsuka, H

2003-05-01

Filled skutterudites SmFe{sub 4}P{sub 12} and SmOs{sub 4}P{sub 12} have been prepared at high temperature and high pressure. The temperature dependence of electrical resistivity in both compounds shows metallic behavior. The magnetic susceptibility and specific heat measurements indicate that SmFe{sub 4}P{sub 12} shows a ferromagnetic ordering at 1.5 K, whereas SmOs{sub 4}P{sub 12} is an antiferromagnet with a T{sub N} of 4.6 K.

Magnetic properties of CeyFe4-xNixSb12

International Nuclear Information System (INIS)

Viennois, R.; Ravot, D.; Tedenac, J.C.; Charar, S.; Mauger, Alain

2005-01-01

The structural and magnetic properties of the metallic skutterudite CeFe 4 Sb 12 have been investigated, with those of Ce y Fe 4-x Ni x Sb z with compositions approaching the relations y=(4-2x)/3, z=12 for which the materials are semiconductors. The large and temperature-dependent contribution of Fe to the magnetic susceptibility of CeFe 4 Sb 12 has been isolated from the Ce contribution, which makes possible a quantitative analysis of the Kondo lattice behavior. In CeFe 4 Sb 12 the Wilson-Sommerfeld ratio is modified by a factor two with respect to former analyses where the magnetic contribution of Fe had been neglected. The main effect of the reduction of the free carrier (hole) concentration in Ce y Fe 4 Sb 12 is to suppress the Kondo effect and the Fe contribution to the magnetic susceptibility. The samples with theoretical hole concentration per unit cell p*=z-8-3y-2x smaller than 0.5 behave like semiconductors in which the exchange between localized Ce 3+ spins is negligible, and are most promising for a potential use as thermoelements

Polar Kerr Effect from Time-Reversal Symmetry Breaking in the Heavy-Fermion Superconductor PrOs4Sb12

Science.gov (United States)

Levenson-Falk, E. M.; Schemm, E. R.; Aoki, Y.; Maple, M. B.; Kapitulnik, A.

2018-05-01

We present polar Kerr effect measurements of the filled skutterudite superconductor PrOs4 Sb12 . Simultaneous ac susceptibility measurements allow us to observe the superconducting transition under the influence of heating from the optical beam. A nonzero Kerr angle θK develops below the superconducting transition, saturating at ˜300 nrad at low temperatures. This result is repeated across several measurements of multiple samples. By extrapolating the measured θK(T ) to zero optical power, we are able to show that the Kerr angle onset temperature in one set of measurements is consistent with the transition to the B phase at TC 2. We discuss the possible explanations for this result and its impact on the understanding of multiphase and inhomogeneous superconductivity in PrOs4 Sb12 .

Inelastic neutron scattering study of crystal field levels in PrOs4As12

International Nuclear Information System (INIS)

Chi, Songxue; Dai, Pengcheng; Barnes, T.F.E.; Kang, H. J.; Lynn, J. W.; Ye, Feng; Maple, M. B.

2008-01-01

We use neutron scattering to study the Pr 3+ crystalline electric field (CEF) excitations in the filled skutterudite PrOs 4 As 12 . By comparing the observed levels and their strengths under neutron excitation with the theoretical spectrum and neutron excitation intensities, we identify the Pr 3+ CEF levels, and show that the ground state is a magnetic Γ 4 (2) triplet, and the excited states Γ 1 , Γ 4 (1) and Γ 23 are at 0.4, 13 and 23 meV, respectively. A comparison of the observed CEF levels in PrOs 4 As 12 with the heavy fermion superconductor PrOs 4 Sb 12 reveals the microscopic origin of the differences in the ground states of these two filled skutterudites

Atomistic explanation of brittle failure of thermoelectric skutterudite CoSb3

International Nuclear Information System (INIS)

Li, Guodong; An, Qi; Goddard, William A.; Hanus, Riley; Zhai, Pengcheng; Zhang, Qingjie; Snyder, G. Jeffrey

2016-01-01

CoSb 3 based skutterudite thermoelectric material has superior thermoelectric properties, but the low fracture toughness prevents its widespread commercial application. To determine the origin of its brittle failure, we examined the response of shear deformation in CoSb 3 along the most plausible slip system (010)/<100>, using large-scale molecular dynamics simulations. We find that the brittle failure of CoSb 3 arises from the formation of shear bands due to the destruction of Sb4-rings and the slippage of Co-octahedraes. This leads to the breakage of Co-octahedraes and cavitation, resulting in the crack opening and mechanical failure.

Structural, electronic and magnetic properties of Pr-based filled skutterudites: A first principle study

Science.gov (United States)

Yadav, Priya; Nautiyal, Shashank; Verma, U. P.

2018-04-01

Ternary skutterudites materials exhibit good electronic properties due to the unpaired d- and f- electrons of the transition and rare-earth metals, respectively. In this communication, we have performed the structural optimization of Pr-based filled skutterudite (PrCo4P12) for the first time and obtained the electronic band structure, density of states and magnetic moments by using the full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). Our obtained magnetic moment of PrCo4P12 is ˜ 1.8 µB in which main contribution is due to Pr atom. Behavior of this material is metallic and it is most stable in body centered cubic (BCC) structure.

Influence of Ni on the thermoelectric properties of the partially filled calcium skutterudites Ca.sub.y./sub.Co.sub.4-x./sub.Ni.sub.x./sub.Sb.sub.12./sub..

Czech Academy of Sciences Publication Activity Database

Puyet, M.; Dauscher, A.; Lenoir, B.; Bellouard, C.; Stiewe, C.; Müller, E.; Hejtmánek, Jiří; Tobola, J.

2007-01-01

Roč. 75, č. 24 (2007), 245110/1-245110/9 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : partially filled skutterudites * thermoelectric properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.172, year: 2007

Photoemission study of the skutterudite compounds CoSb sub 3 and RhSb sub 3

CERN Document Server

Ishii, H; Fujimori, A; Nagamoto, Y; Koyanagi, T; Sofo, J O

2002-01-01

We have studied the electronic structure of the skutterudite compounds CoSb sub 3 and Co(Sb sub 0 sub . sub 9 sub 6 Te sub 0 sub . sub 0 sub 4) sub 3 by photoemission spectroscopy. Valence-band spectra revealed that a significant amount Sb 5p states are present near the Fermi level and are hybridized with Co 3d states just below it. The spectra are well reproduced by the band-structure calculation, suggesting that the effect of electron correlations is not important. When Te is substituted for Sb and n-type carriers are doped into CoSb sub 3 , the spectra are shifted to higher binding energies as described by the rigid-band model. From this shift and the free-electron model for the conduction and valence bands, we have estimated the band gap of CoSb sub 3 to be 0.03-0.04 eV, consistent with transport measurements. Photoemission spectra of RhSb sub 3 have also been measured and revealed expected similarities to and differences from those of CoSb sub 3. Unusual temperature dependence has been observed for the s...

Thermoelectric properties of RuSb2Te ternary skutterudites

Czech Academy of Sciences Publication Activity Database

Navrátil, Jiří; Plecháček, T.; Drašar, Č.; Laufek, F.

2013-01-01

Roč. 42, č. 7 (2013), s. 1864-1869 ISSN 0361-5235 R&D Projects: GA ČR GAP108/10/1315 Institutional support: RVO:61389013 Keywords : RuSb2Te * ternary skutterudite * doping Subject RIV: CA - Inorganic Chemistry Impact factor: 1.675, year: 2013 http://link.springer.com/article/10.1007/s11664-012-2451-5

Muon spin relaxation and rotation studies of the filled skutterudite alloys praseodymium osmium ruthenium antimonide and praseodymium lanthanum osmium antimonide

Science.gov (United States)

Shu, Lei

Some filled skutterudite compounds have recently been found to exhibit very interesting properties. The first Pr-based heavy-fermion superconductor, PrOs4Sb12, is an intriguing material due to the unusual properties of both its normal and superconducting states. Comprehensive muon spin rotation and relaxation studies and magnetic susceptibility measurements, described in this dissertation, have been performed to investigate the microscopic properties of PrOs4Sb12 and its Ru and La doped alloys. The temperature dependence of penetration depth measured in the vortex state of PrOs4Sb12 using transverse-field muon spin rotation (TF-muSR) is weaker than those measured by radiofrequency measurements. A scenario based on two-band superconductivity in PrOs4Sb 12, is proposed to resolve this difference. TF-muSR experiments also suggest the suppression of superfluid density with Ru doping, probably due to impurity scattering. In addition, magnetic susceptibility data as well as analysis of the muSR data in PrOs4Sb12 reveal a nearly linear relation of mu+ Knight shift vs. magnetic susceptibility. This suggests that the muon charge does not affect the crystalline electric field splitting of Pr3+ near neighbors. Additional evidence comes from the fact that the superconducting transition temperature Tc measured from muSR is consistent with the bulk superconducting values. Zero-field muon spin relaxation (ZF-muSR) experiments have been carried out in the Pr(Os1-xRux) 4Sb12 and Pr1-yLayOs 4Sb12 alloy systems to investigate the time-reversal symmetry (TRS) breaking found in an earlier ZF-muSR study of the end compound PrOs 4Sb12. The results from measurements at KEK, Japan, suggest that Ru doping is considerably more efficient than La doping in suppressing TRS breaking superconducting in PrOs4Sb12. However, we think that the spontaneous local field that indicates TRS breaking detected by ZF-muSR may depend on sample quality if those fields are from inhomogeneity in the

f-electron-nuclear hyperfine-coupled multiplets in the unconventional charge order phase of filled skutterudite PrRu4P12

International Nuclear Information System (INIS)

Aoki, Yuji; Namiki, Takahiro; Saha, Shanta R.; Sato, Hideyuki; Tayama, Takashi; Sakakibara, Toshiro; Shiina, Ryousuke; Shiba, Hiroyuki; Sugawara, Hitoshi

2011-01-01

The filled skutterudite PrRu 4 P 12 is known to undergo an unconventional charge order phase transition at 63 K, below which two sublattices with distinct f-electron crystalline-electric-field ground states are formed. In this paper, we study experimentally and theoretically the properties of the charge order phase at very low temperature, particularly focusing on the nature of the degenerate triplet ground state on one of the sublattices. First, we present experimental results of specific heat and magnetization measured with high quality single crystals. In spite of the absence of any symmetry breaking, the specific heat shows a peak structure at T p =0.30 K in zero field; it shifts to higher temperatures as the magnetic field is applied. In addition, the magnetization curve has a remarkable rounding below 1 T. Then, we study the origin of these experimental findings by considering the hyperfine interaction between 4f electron and nuclear spin. We demonstrate that the puzzling behaviors at low temperatures can be well accounted for by the formation of 4f-electron-nuclear hyperfine-coupled multiplets, the first thermodynamical observation of its kind. (author)

Fabrication of stable electrode/diffusion barrier layers for thermoelectric filled skutterudite devices

Energy Technology Data Exchange (ETDEWEB)

Jie, Qing; Ren, Zhifeng; Chen, Gang

2017-08-01

Disclosed are methods for the manufacture of n-type and p-type filled skutterudite thermoelectric legs of an electrical contact. A first material of CoSi.sub.2 and a dopant are ball-milled to form a first powder which is thermo-mechanically processed with a second powder of n-type skutterudite to form a n-type skutterudite layer disposed between a first layer and a third layer of the doped-CoSi.sub.2. In addition, a plurality of components such as iron, and nickel, and at least one of cobalt or chromium are ball-milled form a first powder that is thermo-mechanically processed with a p-type skutterudite layer to form a p-type skutterudite layer "second layer" disposed between a first and a third layer of the first powder. The specific contact resistance between the first layer and the skutterudite layer for both the n-type and the p-type skutterudites subsequent to hot-pressing is less than about 10.0 .mu..OMEGA.cm.sup.2.

Field-orientation dependence of the specific heat of PrOs4Sb12

International Nuclear Information System (INIS)

Custers, Jeroen; Namai, Yukie; Tayama, Takashi; Sakakibara, Toshiro; Sugawara, Hitoshi; Aoki, Yuji; Sato, Hideyuki

2006-01-01

The superconducting (SC) gap of the Pr-based skutterudite PrOs 4 Sb 12 has been investigated by means of field-angle-dependent specific heat C(H,φ) experiments. At fixed temperatures, H was varied and rotated in the basal planes. A 4-fold oscillation of C(H,φ) is observed in the entire H-T SC phase diagram. The minima are located along the [100] directions suggesting the excistence of gap nodes or minima along these directions. The oscillation amplitude vertical bar A vertical bar becomes maximum at H/H c2 ∼0.3. Below, vertical bar A vertical bar->0. The temperature variation of vertical bar A vertical bar follows a quadratic dependence

Photoinduced second harmonic generation of LaFe4Sb12near spin fluctuated critical points

International Nuclear Information System (INIS)

Nouneh, K.; Viennois, R.; Kityk, I.V.; Terki, F.; Charar, S.; Benet, S.; Paschen, S.

2004-01-01

The temperature dependence of the resistivity, the Seebeck coefficient and photoinduced second harmonic generation (PISHG) are studied near the quantum critical point in the skutterudite compound LaFe 4 Sb 12 , possessing increased spin fluctuations. We observed a large maximum of the PISHG at a temperature of about 15 K. The PISHG signal increases substantially below 35 K. We found a correlation between the temperature dependences of PISHG, resistivity and Seebeck coefficient. We proposed a phenomenological explanation for the occurrence of the PISHG signal in LaFe 4 Sb 12 implying strong spin fluctuations exist in this system, which may present some interest for the study of other spin fluctuation systems. Physical insight into the phenomenon observed is grounded in the participation of anharmonic electron-phonon and electron-paramagnon interactions stimulated by inducing light in the interactions with the photoexcited dipole moments. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Low-temperature anomalies of photoinduced second harmonic generation in skutterudites

International Nuclear Information System (INIS)

Viennois, R; Kityk, I V; Terki, F; Charar, S; Muntzer, A; Kasperczyk, J; Ravot, D; Tedenac, J C

2003-01-01

Photoinduced second harmonic generation (PISHG) was found in skutterudite compounds of CeFe 4 Sb 12 and Ce 0.7 Fe 3.5 Ni 0.5 Sb 12 . Measurements versus temperature, pump-probe delaying time and external magnetic field were performed. The studied compounds belong to moderate heavy fermion compounds (HFC) in the ground state. The PISHG signals appear at 6.8 and 4.9 K for CeFe 4 Sb 12 and Ce 0.7 Fe 3.5 Ni 0.5 Sb 12 , respectively. We suspect that these signals are due to anharmonic electron-phonon interactions creating a charge density non-centrosymmetry. The observed effects are caused either by a possible phase transition or by drastic changes in the electron structure of the HFC with decreasing temperature

Influence of high energy β-radiation on thermoelectric performance of filled skutterudites compounds

Energy Technology Data Exchange (ETDEWEB)

Chen, Jikun, E-mail: jikunchen@seas.harvard.edu [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zha, Hao [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China); Xia, Xugui; Qiu, Pengfei; Li, Yulong [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Chuanjing; Han, Yunsheng [Nuctech Company Limited, Beijing (China); Shi, Xun; Chen, Lidong [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Jin, Qingxiu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China); Chen, Huaibi, E-mail: chenhb@mail.tsinghua.edu.cn [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing (China)

2015-08-15

Highlights: • Impact by MeV β-rays irradiation on skutterudite TE material was investigated. • Monte-Carlo simulation is used to simulate the deposited energy irradiations. • The high deposited energy does not change the TE performance. • The light irradiation does not show a significant impact on TE materials. - Abstract: The influence of MeV β-rays irradiation on the thermoelectric performance of n-type filled skutterudite material has been investigated using an electron accelerator. Using a Monte-Carlo simulation base on Fluka code, the deposited energy in the sample material from the irradiation is estimated, which shows a large power deposited around 50 W/mm. Nevertheless, the thermoelectric performances of the filled skutterudite samples are compared before and after irradiations. It indicates that the thermoelectric material will not be easily jeopardized by ‘light’ irradiations with energy lower than MeV range.

Influence of high energy β-radiation on thermoelectric performance of filled skutterudites compounds

International Nuclear Information System (INIS)

Chen, Jikun; Zha, Hao; Xia, Xugui; Qiu, Pengfei; Li, Yulong; Wang, Chuanjing; Han, Yunsheng; Shi, Xun; Chen, Lidong; Jin, Qingxiu; Chen, Huaibi

2015-01-01

Highlights: • Impact by MeV β-rays irradiation on skutterudite TE material was investigated. • Monte-Carlo simulation is used to simulate the deposited energy irradiations. • The high deposited energy does not change the TE performance. • The light irradiation does not show a significant impact on TE materials. - Abstract: The influence of MeV β-rays irradiation on the thermoelectric performance of n-type filled skutterudite material has been investigated using an electron accelerator. Using a Monte-Carlo simulation base on Fluka code, the deposited energy in the sample material from the irradiation is estimated, which shows a large power deposited around 50 W/mm. Nevertheless, the thermoelectric performances of the filled skutterudite samples are compared before and after irradiations. It indicates that the thermoelectric material will not be easily jeopardized by ‘light’ irradiations with energy lower than MeV range

Local distortions about Nd in NdO{sub s4}Sb{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Keiber, T.; Bridges, F. [Department of Physics, University of California, Santa Cruz, California 95064 (United States); Baumbach, R.E. [Los Alamos National Laboratory, New Mexico (United States); Maple, M.B. [Physics Department, University of California, San Diego, California (United States)

2013-02-15

We present an extended X-ray absorption fine structure (EXAFS) study of the NdOs{sub 4}Sb{sub 12} system at the Nd and Os L{sub III} edges. Nd is expected to be a ''rattler'' atom in this skutterudite crystal and we obtain a low Einstein temperature (61 K) as expected. However, although ultrasonic measurements have suggested a large off-center displacement of Nd, the EXAFS data are inconsistent with such a model. An analysis of the first two Os-Sb peaks in the Os L{sub III} data also shows no evidence for unusual disorder. In contrast the Nd-Os peak in the Nd L{sub III} data and the Os-Os peak in the Os L{sub III} data both show significant disorder at 4 K, with the largest disorder found for the Nd-Os pair. This suggests that a distortion of the structure that involves mainly the Os atoms is present; it is likely that this distortion - which may also be dynamic - also causes the anomalies in the ultrasonic data (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Low thermal conductivity skutterudites

Energy Technology Data Exchange (ETDEWEB)

Fleurial, J P; Caillat, T; Borshchevsky, A

1997-07-01

Recent experimental results on semiconductors with the skutterudite crystal structure show that these materials possess attractive transport properties and have a good potential for achieving ZT values substantially larger than for state-of-the-art thermoelectric materials. Both n-type and p-type conductivity samples have been obtained, using several preparation techniques. Associated with a low hole effective mass, very high carrier mobilities, low electrical resistivities and moderate Seebeck coefficients are obtained in p-type skutterudites. For a comparable doping level, the carrier mobilities of n-type samples are about an order of magnitude lower than the values achieved on p-type samples. However, the much larger electron effective masses and Seebeck coefficients on p-type samples. However, the much larger electron effective masses and Seebeck coefficients make n-type skutterudite promising candidates as well. Unfortunately, the thermal conductivities of the binary skutterudites compounds are too large, particularly at low temperatures, to be useful for thermoelectric applications. Several approaches to the reduction of the lattice thermal conductivity in skutterudites are being pursued: heavy doping, formation of solid solutions and alloys, study of novel ternary and filled skutterudite compounds. All those approaches have already resulted in skutterudite compositions with substantially lower thermal conductivity values in these materials. Recently, superior thermoelectric properties in the moderate to high temperature range were achieved for compositions combining alloying and filling of the skutterudite structure. Experimental results and mechanisms responsible for low thermal conductivity in skutterudites are discussed.

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

KAUST Repository

Sarath Kumar, S. R.

2011-10-24

Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single-phase polycrystalline skutterudite films. Raman spectroscopy studies suggested that In and Yb dopants occupy the cage sites in the skutterudite lattice. Low-temperature electrical transport studies revealed the n-type semiconducting nature of the films with extrinsic and intrinsic conduction mechanisms, in sharp contrast to the degenerate nature reported for identical bulk samples. Calculations yielded a direct bandgap close to 50 meV with no evidence of an indirect gap. The carrier concentration of the films was identical to that reported for the bulk and increased with temperature beyond 250 K. The higher resistivity exhibited is attributed to the enhanced grain boundary scattering in films with a high concentration of grains. The maximum power factor of ∼0.68 W m−1 K−1 obtained at 660 K for the film on glass is found to be nearly four times smaller compared to that reported for the bulk. The observed difference in the power factors of the films on different substrates is explained on the basis of the diffusion of oxygen from the substrates and the formation of highly conducting CoSb2 phase upon the oxidation of CoSb3.

Investigations of structural, elastic, electronic and thermodynamic properties of lutetium filled skutterudite LuFe4P12 under pressure effect: FP-LMTO method

Directory of Open Access Journals (Sweden)

Boudia Keltouma

2015-12-01

Full Text Available Structural, elastic, electronic and thermodynamic properties of ternary cubic filled skutterudite compound were calculated. We have computed the elastic modulus and its pressure dependence. From the elastic parameter behavior, it is inferred that this compound is elastically stable and ductile in nature. Through the quasi-harmonic Debye model, in which phononic effects are considered, the effect of pressure P (0 to 50 GPa and temperature T (0 to 3000 °C on the lattice constant, elastic parameters, bulk modulus B, heat capacity, thermal expansion coefficient α, internal energy U, entropy S, Debye temperature θD, Helmholtz free energy A, and Gibbs free energy G are investigated.

Density-functional band-structure calculations for La-, Y-, and Sc-filled CoP3-based skutterudite structures

International Nuclear Information System (INIS)

Loevvik, O.M.; Prytz, O.

2004-01-01

The crystal structure, thermodynamic stability, and electronic structure of La-, Y-, and Sc-filled CoP 3 are predicted from density-functional band-structure calculations. The size of the cubic voids in the skutterudite structure is changed much less than the difference in size between the different filling atoms, and we expect that the larger rattling amplitude of the smaller Sc and Y atoms may decrease the lattice thermal conductivity of Sc- and Y-filled structures significantly compared to La-filled structures. The solubility of La, Y, and Sc in CoP 3 is calculated to be around 5, 3-6 %, and below 1% at 0 K, respectively. Based on similar systems, this is expected to increase considerably if Fe is substituted for Co. Fe substitution is also expected to compensate the increased charge carrier concentration of the filled structures that is seen in the calculated electron density of states. In conclusion, Sc- or Y-filled (FeCo)P 3 skutterudite structures are promising materials for thermoelectric applications

Synthesis, crystal structure, and transport properties of Fe substituted rhombohedral skutterudite derivatives Co4−xFexGe6Se6

KAUST Repository

Wei, Kaya

2014-11-01

We report on the synthesis and low temperature transport properties of rhombohedral derivatives of the cubic skutterudite CoSb3, namely Co4-xFexGe6Se6 with x = 0, 1, 1.5. Rietveld refinement and elemental analyses were used to identify the structure and stoichiometry of the compositions. The thermal conductivity was investigated by employing the Debye model with different phonon-scattering parameters. This investigation demonstrates that Fe substitution is feasible in these skutterudite derivatives and can significantly affect the transport properties as compared with Co4Ge6Se6. © 2014 Elsevier B.V. All rights reserved.

Synthesis, crystal structure, and transport properties of Fe substituted rhombohedral skutterudite derivatives Co4−xFexGe6Se6

KAUST Repository

Wei, Kaya; Dong, Yongkwan; Puneet, Pooja; Tritt, Terry M.; Nolas, George S.

2014-01-01

We report on the synthesis and low temperature transport properties of rhombohedral derivatives of the cubic skutterudite CoSb3, namely Co4-xFexGe6Se6 with x = 0, 1, 1.5. Rietveld refinement and elemental analyses were used to identify the structure and stoichiometry of the compositions. The thermal conductivity was investigated by employing the Debye model with different phonon-scattering parameters. This investigation demonstrates that Fe substitution is feasible in these skutterudite derivatives and can significantly affect the transport properties as compared with Co4Ge6Se6. © 2014 Elsevier B.V. All rights reserved.

Properties of thin N-type Yb0.14Co4Sb12 and P-type Ce0.09Fe0.67Co3.33Sb12 skutterudite layers prepared by laser ablation

Czech Academy of Sciences Publication Activity Database

Zeipl, Radek; Walachová, Jarmila; Lorinčík, J.; Leshkov, Sergey; Josieková, M.; Jelínek, M.; Kocourek, Tomáš; Jurek, Karel; Navrátil, Jiří; Beneš, L.; Plecháček, T.

2010-01-01

Roč. 28, č. 4 (2010), s. 523-527 ISSN 0734-2101 R&D Projects: GA ČR GAP108/10/1315; GA ČR GA203/07/0267 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z40500505; CEZ:AV0Z10100521 Keywords : thermoelectrics * thin layers * skutterudites Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.291, year: 2010

Transport properties of PrxOs4Sb12 single crystals with high Pr-site filling fraction grown under high pressure

International Nuclear Information System (INIS)

Tanaka, Kenya; Namiki, Takahiro; Saito, Takashi; Tatsuoka, Sho; Imamura, Atsushi; Kuwahara, Keitaro; Aoki, Yuji; Sato, Hideyuki

2009-01-01

We have succeeded in growing Pr x Os 4 Sb 12 single crystals under ∼4GPa with high Pr-site filling fraction x. The electrical resistance measurements clearly show that the superconducting (SC) transition is sharper and the onset temperatures is lower in the single crystal samples grown under high pressure compared to that of the sample grown under ambient pressure. These results suggest that the double SC transition ascribed to sample inhomogeneity is suppressed in the sample grown under high pressure. The change of 4f-electron crystalline electric field energy splitting between the Γ 1 ground state and the Γ 4 (2) first excited state in the sample made under high pressure is proposed as one of the possible origins of the suppression of the double SC transition.

High field Moessbauer and magnetic investigations of Pr0.73Fe4Sb12

International Nuclear Information System (INIS)

Reissner, Michael; Bauer, Ernst; Steiner, Walter; Rogl, Peter

2004-01-01

In accordance with the filling factor determined by X-ray investigations two Fe sites were identified in the in-field 57 Fe Moessbauer spectra. The derived internal fields at 4.2 K were small (0.35 and 1.45 T at external fields of 13.5 T), whereas from magnetic measurements μ eff ∼2.7 μ B was estimated for the Fe 4 Sb 12 -sublattice

Thermoelectric property of fine-grained CoSb3 skutterudite compound fabricated by mechanical alloying and spark plasma sintering

International Nuclear Information System (INIS)

Liu Weishu; Zhang Boping; Li Jingfeng; Zhao Lidong

2007-01-01

Skutterudite CoSb 3 polycrystalline materials were prepared using a combined process of mechanical alloying (MA) and spark plasma sintering (SPS). The influence of SPS temperature on the thermoelectric properties was focused in this work with a special emphasis on the analysis of the size effects of grains. The average grain sizes decreased from 300 to 50 nm with decreasing SPS temperatures from 600 to 300 deg. C. The electrical resistivities of samples spark plasma sintered at 300-600 deg. C all decreased with increasing temperature, indicating a classic intrinsic conduction behaviour of semiconductors. The samples spark plasma sintered at 300-500 deg. C showed a positive Seebeck coefficient while the sample spark plasma sintered at 600 deg. C showed a negative Seebeck coefficient. The room-temperature thermal conductivities were reduced from 4.30 to 2.92 W m -1 K -1 as the grain sizes were decreased from 300 to 100 nm corresponding to SPS at 600 and 400 deg. C, respectively. The present work indicates that MA and SPS is a good combination for fabricating fine-grained CoSb 3 thermoelectric materials

On the chemical synthesis route to bulk-scale skutterudite materials

DEFF Research Database (Denmark)

Tafti, Mohsen Y.; Saleemi, Mohsin; Han, Li

2016-01-01

In this article an alternative high yield route for the synthesis of CoSb3-based unfilled skutterudites is presented. Using low-melting temperature salts of the constituents, melting and mixing them homogeneously in a hydrophobic liquid with postprocessing of the powders we achieve a more intimat......, compaction of the powders with SPS technique provided a safe route to maintaining the nanopowder size and achieving low thermal conductivity (3 W/mK). The proposed method can easily be scaled up and adopted by the industry.......In this article an alternative high yield route for the synthesis of CoSb3-based unfilled skutterudites is presented. Using low-melting temperature salts of the constituents, melting and mixing them homogeneously in a hydrophobic liquid with postprocessing of the powders we achieve a more...

Pulsed laser deposition and thermoelectric properties of In-and Yb-doped CoSb3 skutterudite thin films

KAUST Repository

Sarath Kumar, S. R.

2011-07-29

In-and Yb-doped CoSb3 thin films were prepared by pulsed laser deposition. Process optimization studies revealed that a very narrow process window exists for the growth of single-phase skutterudite films. The electrical conductivity and Seebeck coefficient measured in the temperature range 300-700 K revealed an irreversible change on the first heating cycle in argon ambient, which is attributed to the enhanced surface roughness of the films or trace secondary phases. A power factor of 0.68 W m-1 K-1 was obtained at ∼700 K, which is nearly six times lower than that of bulk samples. This difference is attributed to grain boundary scattering that causes a drop in film conductivity. Copyright © Materials Research Society 2011.

Triplet superconductivity in PrOs4Sb12

International Nuclear Information System (INIS)

Maki, K.; Won, H.; Parker, David; Haas, Stephan; Izawa, K.; Matsuda, Y.

2005-01-01

Here we propose spin triplet superconductors for the A- and B-phase in PrOs 4 Sb 12 . The present model describes consistently the thermal conductivity κ zz data obtained by Izawa et al. for T>=150mK

Electronic band structures of binary skutterudites

Energy Technology Data Exchange (ETDEWEB)

Khan, Banaras [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan); Aliabad, H.A. Rahnamaye [Department of Physics, Hakim Sabzevari University, Sabzevar (Iran, Islamic Republic of); Saifullah [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan); Jalali-Asadabadi, S. [Department of Physics, Faculty of Science, University of Isfahan (UI), 81744 Isfahan (Iran, Islamic Republic of); Khan, Imad [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan); Ahmad, Iftikhar, E-mail: ahma5532@gmail.com [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan)

2015-10-25

The electronic properties of complex binary skutterudites, MX{sub 3} (M = Co, Rh, Ir; X = P, As, Sb) are explored, using various density functional theory (DFT) based theoretical approaches including Green's Function (GW) as well as regular and non-regular Tran Blaha modified Becke Jhonson (TB-mBJ) methods. The wide range of calculated bandgap values for each compound of this skutterudites family confirm that they are theoretically as challenging as their experimental studies. The computationally expensive GW method, which is generally assume to be efficient in the reproduction of the experimental bandgaps, is also not very successful in the calculation of bandgaps. In this article, the issue of the theoretical bandgaps of these compounds is resolved by reproducing the accurate experimental bandgaps, using the recently developed non-regular TB-mBJ approach, based on DFT. The effectiveness of this technique is due to the fact that a large volume of the binary skutterudite crystal is empty and hence quite large proportion of electrons lie outside of the atomic spheres, where unlike LDA and GGA which are poor in the treatment of these electrons, this technique properly treats these electrons and hence reproduces the clear electronic picture of these compounds. - Highlights: • Theoretical and experimental electronic band structures of binary skutterudites are reviewed. • The literature reveals that none of the existing theoretical results are consistent with the experiments. • GW, regular and non-regular TB-mBJ methods are used to reproduce the correct results. • The GW and regular TB-mBJ results are better than the available results in literature. • However, non-regular TB-mBJ reproduces the correct experimental band structures.

Electronic band structures of binary skutterudites

International Nuclear Information System (INIS)

Khan, Banaras; Aliabad, H.A. Rahnamaye; Saifullah; Jalali-Asadabadi, S.; Khan, Imad; Ahmad, Iftikhar

2015-01-01

The electronic properties of complex binary skutterudites, MX 3 (M = Co, Rh, Ir; X = P, As, Sb) are explored, using various density functional theory (DFT) based theoretical approaches including Green's Function (GW) as well as regular and non-regular Tran Blaha modified Becke Jhonson (TB-mBJ) methods. The wide range of calculated bandgap values for each compound of this skutterudites family confirm that they are theoretically as challenging as their experimental studies. The computationally expensive GW method, which is generally assume to be efficient in the reproduction of the experimental bandgaps, is also not very successful in the calculation of bandgaps. In this article, the issue of the theoretical bandgaps of these compounds is resolved by reproducing the accurate experimental bandgaps, using the recently developed non-regular TB-mBJ approach, based on DFT. The effectiveness of this technique is due to the fact that a large volume of the binary skutterudite crystal is empty and hence quite large proportion of electrons lie outside of the atomic spheres, where unlike LDA and GGA which are poor in the treatment of these electrons, this technique properly treats these electrons and hence reproduces the clear electronic picture of these compounds. - Highlights: • Theoretical and experimental electronic band structures of binary skutterudites are reviewed. • The literature reveals that none of the existing theoretical results are consistent with the experiments. • GW, regular and non-regular TB-mBJ methods are used to reproduce the correct results. • The GW and regular TB-mBJ results are better than the available results in literature. • However, non-regular TB-mBJ reproduces the correct experimental band structures

Studies of bulk materials for thermoelectric cooling

Energy Technology Data Exchange (ETDEWEB)

Sharp, J W; Nolas, G S; Volckmann, E H

1997-07-01

The authors discuss ongoing work in three areas of thermoelectric materials research: (1) broad band semiconductors featuring anion networks, (2) filled skutterudites, and (3) polycrystalline Bi-Sb alloys. Key results include: a preliminary evaluation of a previously untested ternary semiconductor, KSnSb; the first reported data in which Sn is used as a charge compensator in filled antimonide skutterudites; the finding that Sn doping does not effect polycrystalline Bi{sub 1{minus}x}Sb{sub x} as it does single crystal samples.

101Ru NQR study in superconducting CeRu2

International Nuclear Information System (INIS)

Matsuda, Kazuyuki; Kohori, Yoh; Kohara, Takao

1995-01-01

We present measurements of the NQR spectrum and the nuclear spin lattice relaxation rate, 1/T 1 , of 101 Ru in superconducting CeRu 2 from 1.9 K to 10 K. From the NQR spectrum, the electric quadrupole interaction parameters were determined to be ν Q =13.2 MHz and η=0.1/T 1 varies in proportion to temperature in the normal state, and has the Hebel-Slichter coherence peak just below the superconducting transition temperature, T C , of 6.2 K, and decreases exponentially at low temperatures with the energy gap of 2Δ=4.0k B T C . 101 Ru NQR study indicates that CeRu 2 is an s-wave and strong-coupling superconductor. (author)

Anomalous enhancement of the lower critical field deep in the superconducting state of LaRu4As12

Science.gov (United States)

Juraszek, J.; Bochenek, Ł.; Wawryk, R.; Henkie, Z.; Konczykowski, M.; Cichorek, T.

2018-05-01

LaRu4As12 with the critical temperature Tc = 10.4 K displays several features which point at a non-singlet superconducting order parameter, although the bcc crystal structure of the filled skutterudites does not favour the emergence of multiple energy gaps. LaRu4As12 displays an unexpected enhancement of the lower critical field deep in superconducting state which can be attributed to the existence of two superconducting gaps. At T = 0.4 K, the local magnetization measurements were performed utilizing miniaturized Hall sensors.

Effect of laser irradiation on Ag4In12Sb56Te28

Science.gov (United States)

Chinnusamy, Rangasami

2018-04-01

Ag4In12Sb56Te28 has been synthesized by melt-quench method. Phase homogeneity, crystal structure and effect of laser irradiation have been investigated using X-ray diffraction (XRD) and Raman spectroscopy. Rietveld refinement of crystal structure revealed that Ag4In12Sb56Te28 is a multiphase system with AgIn3Te5, Sb8Te3 and Sb phases. Combined optical microscopy and Raman spectroscopy have been used to understand the distribution of different phases on the surface of the samples, which substantiated the results of Rietveld analysis. Interaction of 20 mW laser beam with samples has been investigated using Raman measurements. The results have shown that regions with large phase fraction of AgIn3Te5 become amorphous during laser-sample interaction, but the starting phase remains nearly same after the interaction. Regions with AgIn3Te5 and nearly equal or larger amount of Sb8Te3 have shown significant growth of α-Sb2O3 during and after laser-sample interaction. Regions rich in Sb have shown formation of AgIn3Te5 and growth of α-Sb2O3 during and after interaction. These observations have been explained based on the maximum temperature rise at different regions during laser-sample interaction.

Triplet superconductivity in PrOs{sub 4}Sb{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Maki, K. [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Won, H. [Department of Physics, Hallym University Chuncheon 200-702 (Korea, Republic of) ]. E-mail: hkwon@hallym.ac.kr; Parker, David [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Haas, Stephan [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Izawa, K. [Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Matsuda, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

2005-04-30

Here we propose spin triplet superconductors for the A- and B-phase in PrOs{sub 4}Sb{sub 12}. The present model describes consistently the thermal conductivity {kappa}{sub zz} data obtained by Izawa et al. for T>=150mK.

Crystalline-electric field of Pr(Os1-xRux)4Sb12

International Nuclear Information System (INIS)

Akita, H.; Yoshino, G.; Ochiai, A.

2006-01-01

High-quality single crystals of Pr(Os 1-x Ru x ) 4 Sb 12 were grown by the Sb self-flux method. Magnetic susceptibility χ(T) was measured precisely. The characteristic temperature T max , where χ(T) exhibits a maximum, varies as a function of Ru-content x but its functional form changes at around x=0.6 where competition of two types of superconductivity is suggested. Since T max is thought to be relevant to the splitting energy between a ground state and a first excited state, we analyzed χ(T) considering the crystalline electric field (CEF) of the T h symmetry. χ(T) is well fitted assuming a Γ 1 singlet ground state for all x values. As expected from T max , the energy of the first excited state (Γ 4 (2) ) changes its functional form at around x=0.6. Furthermore, the energies of the second and third excited states (Γ 4 (1) and Γ 23 ) exhibit a minimum at almost the same value of x=0.6. These results suggest that the CEF is related to the superconductivity in Pr(Os 1-x Ru x ) 4 Sb 12

Effects of FeSb6 octahedral deformations on the electronic structure of LaFe4Sb12

KAUST Repository

Pulikkotil, Jiji Thomas Joseph

2011-09-01

First-principles density functional based electronic structure calculations are performed in order to clarify the influence of FeSb6 octahedral deformations on the structural and electronic structure properties of LaFe 4Sb12. Our results show that octahedral tiltings correlate with the band dispersions and, consequently, the band masses. While total energy variation points at an enhanced role of lattice anharmonicity, flat bands emerge from a redistribution of the electronic states. © 2011 Elsevier B.V. All rights reserved.

Photoemission of heavy fermion superconductor PrOs4Sb12 and other Pr compounds

International Nuclear Information System (INIS)

Imada, S.; Yamasaki, A.; Sekiyama, A.; Settai, R.; Onuki, Y.; Suga, S.; Sugawara, H.; Sato, H.; Ochiai, A.

2004-01-01

Full text: Strongly correlated electronic states due to Pr 4f electrons found in several Pr compounds have recently been attracting much attention. The Pr 4f electrons are much more localized than in Ce due to the lanthanoid contraction. Therefore, the number of the Pr systems that show strong electron correlation is much smaller than Ce systems. We will present a comparative study of Pr 4f electronic states in such systems as the heavy fermion superconductor PrOs 4 Sb 12 , the Kondo system PrSn 3 and the localized 4f systems Pr 4 X 3 (X = Sb and Bi). The Pr 4f electronic state was probed by means of the Pr 3d → 4f resonant photoemission (RPES). Because the kinetic energy (E K ) of the photoelectrons is as high as ∼ 900 eV, this method is much more bulk sensitive than the 4d → 4f RPES with E K ∼ 100 eV. The energy resolution could be set to about 100 meV by utilizing the soft X-rays from BL25SU in SPring-8 and the SCIENTA SES-200 analyzer. The Pr 4f excitation spectrum of PrSn 3 was found to show a very strong intensity at the Fermi level (E F ). This can be interpreted as the Kondo resonance which has been observed in the Kondo Ce and Yb compounds. In the Pr 4f spectrum of the heavy fermion superconductor PrOs 4 Sb 12 , the intensity at E F was smaller than in PrSn 3 . This clearly shows that the Kondo temperature (T K ) is much lower in PrOs 4 Sb 12 than in PrSn 3 . We have further found a strong excitation energy dependence in the RPES line shape. In the case of Pr 4 X 3 (X = Sb and Bi), the intensity at E B was much smaller than PrSn 3 and PrOs 4 Sb 12 , which is consistent with the localized character of Pr 4f electrons in Pr 4 X 3 . The Pr 4f spectra of these localized systems are qualitatively well reproduced by a cluster model calculation that takes into account the hybridization between the Pr 4f orbital and the conduction and valence bands made up by the X p and Pr 5d states

Influence of thickness on properties of YbxCo4Sb12 layers prepared by laser ablation

Czech Academy of Sciences Publication Activity Database

Zeipl, Radek; Jelínek, M.; Kocourek, Tomáš; Navrátil, Jiří; Yatskiv, Roman; Josieková, M.; Leshkov, Sergey; Jurek, Karel; Walachová, Jarmila

2010-01-01

Roč. 12, č. 3 (2010), s. 572-575 ISSN 1454-4164 R&D Projects: GA ČR GA203/07/0267 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z40500505; CEZ:AV0Z10100521 Keywords : thermoelectrics * thin layers * skutterudites Subject RIV: JA - Electronics ; Optoelectronics , Electrical Engineering Impact factor: 0.412, year: 2010

Alternative synthetic route for the heterometallic CO-releasing [Sb@Rh12(CO27]3− icosahedral carbonyl cluster and synthesis of its new unsaturated [Sb@Rh12(CO24]4− and dimeric [{Sb@Rh12Sb(CO25}2Rh(CO2PPh3]7− derivatives

Directory of Open Access Journals (Sweden)

Cristina Femoni

2016-10-01

Full Text Available The hetero-metallic [Sb@Rh12(CO27]3− cluster has been known as for over three decades thanks to Vidal and co-workers, and represents the first example of an E-centered (E=heteroatom icosahedral rhodium carbonyl cluster. However, its synthesis required high temperature (140–160 °C and elevated CO pressure (400 atm. Applying the redox condensation method for cluster preparation, we herein report a new synthetic, high-yield route for preparing [Sb@Rh12(CO27]3− under much milder conditions of temperature and pressure. Notably, when the same synthesis was carried out under N2 instead of CO atmosphere, the new isostructural but unsaturated derivative [Sb@Rh12(CO24]4− was obtained, for which we report the full X-ray structural characterization. This species represents one of the few examples of an icosahedral cluster disobeying the electron-counting Wade-Mingos rules, possessing less than the expected 170 cluster valence electrons (CVEs. Judging from IR monitoring, the two species can be obtained one from the other by switching between N2 and CO atmosphere, making [Sb@Rh12(CO27]3− a spontaneous CO-releasing molecule. Finally, the study of the chemical reactivity of [Sb@Rh12(CO27]3− with PPh3 allowed us to obtain the new [{Sb@Rh12Sb(CO25}2Rh(CO2PPh3]7− dimeric compound, for which we herein report the full X-ray structural and 31P NMR analyses.

Ultrasonic dispersion and off-center rattling in heavy fermion superconductor PrOs4Sb12

International Nuclear Information System (INIS)

Nemoto, Yuichi; Ueno, Takafumi; Takeda, Naoya; Yamaguchi, Takashi; Yanagisawa, Tatsuya; Goto, Terutaka; Sugawara, Hitoshi; Sato, Hideyuki

2006-01-01

Ultrasonic attenuation measurements have been firstly performed for a large single crystal of PrOs 4 Sb 12 with the dimensions of 5.97x0.6x0.6mm 3 . Remarkable frequency dependence around 20-40K has been observed in the elastic constant and attenuation coefficient of the longitudinal C 11 mode associated with E g symmetry strain in part, which results from a thermally activated off-center rattling with E g symmetry of a Pr ion inside a Sb icosahedron cage. Parameters of a characteristic time τ 0 =3.1x10 -11 s and an activation energy E=225K were obtained. This E g rattling involving a local charge fluctuation inside a Sb cage periodically arranged may couple to the conduction electrons. As a result, the electron-phonon coupling would lead to heavy fermion and its superconductivity in PrOs 4 Sb 12

Superconductivity and transport properties in LaRu4Sb12 single crystals probed by radiation-induced disordering

International Nuclear Information System (INIS)

Goshchitskii, B.; Naumov, S.; Kostromitina, N.; Karkin, A.

2007-01-01

Resistivity ρ(T) and Hall coefficient R H (T) in magnetic fields H up to 14 T were studied in superconducting (T c = 3.3 K) LaRu 4 Sb 12 single crystals disordered by fast neutron irradiation. Atomic disordering leads to increase in residual resistivity ρ 0 , decrease of Hall number and suppression of superconductivity. The upper critical field slope -dH c2 /dT increases approximately linear with ρ 0 . The irradiation effects are almost recovered after annealing at 500 deg. C. The observed radiation-induced effects in LaRu 4 Sb 12 are compared with those in PrOs 4 Sb 12 in terms of unconventional mechanisms of superconductivity

Thermoelectric properties of Co4Sb12 with Bi2Te3 nanoinclusions.

Science.gov (United States)

Ghosh, Sanyukta; Bisht, Anuj; Karati, Anirudha; Rogl, Gerda; Rogl, Peter; Murty, B S; Suwas, Satyam; Mallik, Ramesh Chandra

2018-02-12

The figure of merit (zT) of a thermoelectric material can be enhanced by incorporation of nanoinclusions into bulk material. The presence of bismuth telluride (Bi 2 Te 3 ) nanoinclusions in Co 4 Sb 12 leads to lower phonon thermal conductivity by introducing interfaces and defects; it enhances the average zT between 300-700 K. In the current study, Bi 2 Te 3 nanoparticles were dispersed into bulk Co 4 Sb 12 by ball-milling. The bulk was fabricated by spark plasma sintering. The presence of Bi 2 Te 3 dispersion in Co 4 Sb 12 was confirmed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron back scattered diffraction technique. Energy dispersive spectroscopy showed antimony (Sb) as an impurity phase for higher contents of Bi 2 Te 3 in the sample. The Seebeck coefficient (S) and electrical conductivity (σ) were measured in the temperature range of 350-673 K. The negative value of S indicates that most of the charge carriers were electrons. A decrease in S and increase in σ with Bi 2 Te 3 content are due to the increased carrier concentration, as confirmed by Hall measurement. The thermal conductivity, measured between 423-673 K, decreased due to the increased phonon scattering at interfaces. A maximum zT of 0.17 was achieved at 523 K and it did not vary much throughout the temperature range. The experimental results of composites were compared by using effective medium theories.

Thermoelectric properties of Co4Sb12 with Bi2Te3 nanoinclusions.

Science.gov (United States)

Ghosh, Sanyukta; Bisht, Anuj; Karati, Anirudha; Rogl, Gerda; Rogl, Peter F; Murty, B S; Suwas, Satyam; Mallik, Ramesh Chandra

2018-01-08

The figure of merit (zT) of a thermoelectric material can be enhanced by incorporation of nanoinclusions into bulk material. The presence of bismuth telluride (Bi2Te3) nanoinclusions in Co4Sb12 leads to lower phonon thermal conductivity by introducing interfaces and defects; it enhances the average zT between 300-700 K. In the current study, Bi2Te3 nanoparticles were dispersed into bulk Co4Sb12 by ball-milling. The bulk was fabricated by spark plasma sintering (SPS). The presence of Bi2Te3 dispersion in Co4Sb12 was confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron back scattered diffraction (EBSD) technique. Energy dispersive spectroscopy (EDS) showed antimony (Sb) as an impurity phase for higher contents of Bi2Te3 in the sample. The Seebeck coefficient (S) and electrical conductivity () were measured in the temperature range of 350 - 673 K. The negative value of S indicates that most of the charge carriers were electrons. A decrease in S and increase in with Bi2Te3 content are due to the increased carrier concentration, as confirmed by Hall measurement. The thermal conductivity, measured between 423 - 673 K, decreased due to the increased phonon scattering at interfaces. A maximum zT of 0.17 was achieved at 523 K and it did not vary much throughout the temperature range. The experimental results of composites were compared by using effective medium theories. © 2018 IOP Publishing Ltd.

Optical study on metal-insulator change in PrFe4P12 under high pressure

International Nuclear Information System (INIS)

Irizawa, Akinori; Sato, Kazuyuki; Kobayashi, Masayo; Nanba, Takao; Matsunami, Masaharu; Sugawara, Hitoshi; Sato, Hideyuki

2007-01-01

The optical study has been performed on filled-skutterudite PrFe 4 P 12 applying pressure up to 16 GPa. The reflectivity at far-infrared (FIR) region showed that the metallic reflectivity looses its intensity and the weak phonon peaks at ambient pressure become prominent with pressures at lower temperature. It insists that the electronic states near Fermi level in this compound changes drastically from metallic properties to insulating ones at high pressures and low temperatures, and the insulating phase persists up to 16 GPa against the electrical resistivity data under pressure

スクッテルド鉱型化合物LnRu4P12(Ln=ランタニド)の構造と電子物性

OpenAIRE

内海, 貴徳; 関根, ちひろ; 木村, 繁之; 井上, 雅士; 城谷, 一民

1999-01-01

Ternary ruthenium phosphides LnRu4P12 (Ln=La,Ce,Pr,Nd,Sm,Eu,Gd and Tb) with the filled skutterudite-type structure have been prepared at high temperatures and high pressures. The crystal structure of a new compound TbRu4P12 is refined by the Rietveld analysis of the powder X-ray diffraction data. The physical properties of LnRu4P12 have been studied by means of electrical resistivity, magnetic susceptibility, magnetization and specific-heat measurements at low temperatures. LaRu4P12 is a supe...

Synthesis and thermoelectric properties of Sb{sub 0.20}CoSb{sub 2.80} skutterudite

Energy Technology Data Exchange (ETDEWEB)

Figueirêdo, C.A., E-mail: camila_fig@hotmail.com [Universidade Federal do Rio Grande do Sul, PGCIMAT, Instituto de Física, 91501-970 Porto Alegre, RS (Brazil); Gallas, M.R. [Universidade Federal do Rio Grande do Sul, PGCIMAT, Instituto de Física, 91501-970 Porto Alegre, RS (Brazil); Institute for Multiscale Simulations, Friedrich-Alexander-Universität, Nägelsbachstrasse 49b, 91052 Erlangen (Germany); Zorzi, J.E. [Universidade de Caxias do Sul, Instituto de Materiais Cerâmicos, 95765-000 Bom Princípio, RS (Brazil); Perottoni, C.A. [Universidade Federal do Rio Grande do Sul, PGCIMAT, Instituto de Física, 91501-970 Porto Alegre, RS (Brazil); Universidade de Caxias do Sul, Instituto de Materiais Cerâmicos, 95765-000 Bom Princípio, RS (Brazil)

2014-06-15

Highlights: • A HP-HT Sb{sub 0.20}CoSb{sub 2.80} phase was prepared by processing cobalt antimonide at 7.7 GPa and 550 °C, for (at least) 5 min. • The mechanism of formation of this phase involves (i) decomposition of cobalt antimonide into CoSb{sub 2} and Sb, and (ii) insertion of Sb into the remaining cobalt antimonide. • The mechanism of formation is qualitatively different from that responsible for the formation of the high pressure (greater than 20 GPa) phase. - Abstract: Polycrystalline samples of cobalt antimonide (CoSb{sub 2.79}) were submitted to different conditions of pressure, temperature and processing time, in a high-pressure toroidal-type chamber, aiming to maximize the production of the high pressure phase previously observed in experiments with a diamond anvil cell. Rietveld refinements of X-ray powder diffraction data were performed to determine the phase composition and structural parameters. The maximum yield, 89(2) wt.% of Sb{sub x}CoSb{sub 3−x} phase, was obtained at 7.7 GPa, 550 °C and (at least) 5 min of processing time. The mechanism behind the formation of Sb{sub x}CoSb{sub 3−x} at high pressure and high temperature is actually not the same as that previously inferred from experiments at higher pressures (20 GPa) and room temperature with the diamond anvil cell. Indeed, evidences suggest that, at high pressure and high temperature, Sb{sub x}CoSb{sub 3−x} is formed by insertion of Sb resulting from decomposition of cobalt antimonide. Thermal conductivity, Seebeck coefficient and electrical conductivity were estimated for CoSb{sub 2.79} and Sb{sub 0.20}CoSb{sub 2.80}. The thermoelectric figure of merit at room temperature for Sb{sub 0.20}CoSb{sub 2.80} resulted 33% greater than that for CoSb{sub 2.79}.

Single crystal growth and electrical and magnetic measurements on CeFe4Sb12

International Nuclear Information System (INIS)

Mori, I.; Sugawara, H.; Magishi, K.; Saito, T.; Koyama, K.; Kikuchi, D.; Tanaka, K.; Sato, H.

2007-01-01

We have succeeded in growing single crystals of CeFe 4 Sb 12 by a Sb-self-flux method and measured the electrical resistivity and magnetization. The residual resistivity is about two times smaller than that of polycrystalline ones, suggesting that the sample quality is highly improved. The magnetization measurements at low temperature revealed that the sample contains almost no magnetic impurities which are always observed in polycrystalline samples. The weak temperature dependence and a broad maximum around 115K in magnetic susceptibility, which is a typical feature of valence fluctuation compounds, have been observed

Thermoelectric skutterudite compositions and methods for producing the same

Science.gov (United States)

Ren, Zhifeng; Yang, Jian; Yan, Xiao; He, Qinyu; Chen, Gang; Hao, Qing

2014-11-11

Compositions related to skutterudite-based thermoelectric materials are disclosed. Such compositions can result in materials that have enhanced ZT values relative to one or more bulk materials from which the compositions are derived. Thermoelectric materials such as n-type and p-type skutterudites with high thermoelectric figures-of-merit can include materials with filler atoms and/or materials formed by compacting particles (e.g., nanoparticles) into a material with a plurality of grains each having a portion having a skutterudite-based structure. Methods of forming thermoelectric skutterudites, which can include the use of hot press processes to consolidate particles, are also disclosed. The particles to be consolidated can be derived from (e.g., grinded from), skutterudite-based bulk materials, elemental materials, other non-Skutterudite-based materials, or combinations of such materials.

High temperature neutron powder diffraction study of the Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} phases

Energy Technology Data Exchange (ETDEWEB)

Lemoine, Pierric, E-mail: pierric.lemoine@univ-rennes1.fr [Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex (France); Bourgès, Cédric; Barbier, Tristan [Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04 (France); Nassif, Vivian [CNRS Institut NEEL, F-38000 Grenoble (France); Université de Grenoble Alpes, Institut NEEL, F-38000 Grenoble (France); Cordier, Stéphane [Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex (France); Guilmeau, Emmanuel [Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04 (France)

2017-03-15

Ternary copper-containing sulfides Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} have attracted considerable interest since few years due to their high-efficiency conversion as absorbers for solar energy and promising thermoelectric materials. We report therein on the decomposition study of Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} phases using high temperature in situ neutron powder diffraction. Our results obtained at a heating rate of 2.5 K/min indicate that: (i) Cu{sub 12}Sb{sub 4}S{sub 13} decomposes above ≈792 K into Cu{sub 3}SbS{sub 3}, and (ii) Cu{sub 4}Sn{sub 7}S{sub 16} decomposes above ≈891 K into Sn{sub 2}S{sub 3} and a copper-rich sulfide phase of sphalerite ZnS-type structure with an assumed Cu{sub 3}SnS{sub 4} stoichiometry. Both phase decompositions are associated to a sulfur volatilization. While the results on Cu{sub 12}Sb{sub 4}S{sub 13} are in fair agreement with recent published data, the decomposition behavior of Cu{sub 4}Sn{sub 7}S{sub 16} differs from other studies in terms of decomposition temperature, thermal stability and products of reaction. Finally, the crystal structure refinements from neutron powder diffraction data are reported and discussed for the Cu{sub 4}Sn{sub 7}S{sub 16} and tetrahedrite Cu{sub 12}Sb{sub 4}S{sub 13} phases at 300 K, and for the high temperature form of skinnerite Cu{sub 3}SbS{sub 3} at 843 K. - Graphical abstract: In situ neutron powder diffraction data (heating rate of 2.5 K/min) indicates that (i) the ternary Cu{sub 12}Sb{sub 4}S{sub 13} phase is stable up to 792 K and decomposes at higher temperature into Cu{sub 3}SbS{sub 3} and Cu{sub 1.5}Sb{sub 0.5}S{sub 2}, and (ii) the Cu{sub 4}Sn{sub 7}S{sub 16} phase is stable up to 891 K and decomposes at higher temperature into Sn{sub 2}S{sub 3} and a cubic phase of sphalerite ZnS-type structure. Sulfur volatilization likely occurs in order to balance the overall stoichiometry.

Transport and magnetic properties of CezLa1-zFe4Sb12

International Nuclear Information System (INIS)

Viennois, R; Charar, S; Ravot, D; Mauger, A; Haen, P; Tedenac, J C

2006-01-01

Transport and magnetic properties of Ce z La 1-z Fe 4 Sb 12 have been investigated in the whole range of substitution 0 Ce to the resistivity goes through a maximum at temperature ∼ 140K, close to the spin fluctuation temperature T sf for CeFe 4 Sb 12 . T sf is the single magnetic energy scale which accounts for the magnetic properties of the Ce Kondo lattice. At low temperature, the resistivity shows a T 2 -deviation from saturation. At z≤0.7 this is the behaviour expected for Ce impurities in metals in the Kondo limit. At z = 1, however, Hall effect measurements show that this behaviour is due to a decrease of the free carrier concentration which we can attribute to the formation of a hybridization pseudogap E g ∼ 25 meV. Upon dilution of the cerium, E g decreases and this pseudogap is smeared out, replaced by the Kondo resonance at the Fermi level characteristic of Kondo impurities in the small z limit

Nanoscale thermoelectric materials

International Nuclear Information System (INIS)

Failamani, F.

2015-01-01

Thermoelectric (TE) materials directly convert thermal energy to electrical energy when subjected to a temperature gradient, whereas if electricity is applied to thermoelectric materials, a temperature gradient is formed. The performance of thermoelectric materials is characterized by a dimensionless figure of merit (ZT = S2T/ρλ), which consists of three parameters, Seebeck coefficient (S), electrical resistivity (ρ) and thermal conductivity (λ). To achieve good performance of thermoelectric power generation and cooling, ZT's of thermoelectric materials must be as high as possible, preferably above unity. This thesis comprises three main parts, which are distributed into six chapters: (i) nanostructuring to improve TE performance of trivalent rare earth-filled skutterudites (chapter 1 and 2), (ii) interactions of skutterudite thermolectrics with group V metals as potential electrode or diffusion barrier for TE devices (chapter 3 and 4), and (iii) search for new materials for TE application (chapter 5 and 6). Addition of secondary phases, especially nano sized phases can cause additional reduction of the thermal conductivity of a filled skutterudite which improves the figure of merit (ZT) of thermoelectric materials. In chapter 1 we investigated the effect of various types of secondary phases (silicides, borides, etc.) on the TE properties of trivalent rare earth filled Sb-based skutterudites as commercially potential TE materials. In this context the possibilty to introduce borides as nano-particles (via ball-milling in terms of a skutterudite/boride composite) is also elucidated in chapter 2. As a preliminary study, crystal structure of novel high temperature FeB-type phases found in the ternary Ta-{Ti,Zr,Hf,}-B systems were investigated. In case of Ti and Hf this phase is the high temperature stabilization of binary group IV metal monoborides, whereas single crystal study of (Ta,Zr)B proves that it is a true ternary phase as no stable monoboride exist in the

Microstructure and thermoelectric properties of doped p-type CoSb3 under TGZM effect

Science.gov (United States)

Wang, Hongqiang; Li, Shuangming; Li, Xin; Zhong, Hong

2017-05-01

The Co-96.9 wt% Sb hypoeutectic alloy doped by 0.12 wt% YbFe was solidified in a Bridgman-type furnace based on temperature gradient zone melting (TGZM) effect. A mushy zone was observed between the complete liquid zone and the solid zone at different thermal stabilization time ranging from 15 min to 40 h. The mushy-zone solidified microstructures of the alloy only consist of CoSb3 and Sb phase. After 40 h thermal stabilization time, the volume fraction of CoSb3 in the mushy zone increases significantly up to 99.6% close to the solid-liquid interface. The hardness and fracture toughness of doped CoSb3 can reach 7.01 ± 0.69 GPa and 0.78 ± 0.08 MPa·m1/2, respectively. Meanwhile, the thermoelectric properties of the alloy were measured ranging from room temperature (RT) to 850 K. The Seebeck coefficient of the specimen prepared by TGZM effect after 40 h could reach 155 μV/K and the ZT value is 0.47 at 660 K, showing that it is feasible to prepare CoSb3 bulk material via TGZM effect. As a simple and one-step solidification method, the TGZM technique could be applied in the preparation of skutterudite compounds.

Fabrication and Thermoelectric Properties of n-Type CoSb2.85Te0.15 Using Selective Laser Melting.

Science.gov (United States)

Yan, Yonggao; Ke, Hongquan; Yang, Jihui; Uher, Ctirad; Tang, Xinfeng

2018-04-25

We report a nonequilibrium fabrication method of n-type CoSb 2.85 Te 0.15 skutterudites using selective laser melting (SLM) technology. A powder of CoSb 2.85 Te 0.15 was prepared by self-propagating high-temperature synthesis (SHS) and served as the raw material for the SLM process. The effect of SLM processing parameters such as the laser power and scanning speed on the quality of the forming CoSb 2.85 Te 0.15 thin layers was systematically analyzed, and the optimal processing window for SLM was determined. A brief postannealing at 450 °C for 4 h, following the SLM process, has resulted in a phase-pure CoSb 2.85 Te 0.15 bulk material deposited on a Ti substrate. The Seebeck coefficient of the annealed SLM prepared bulk material is close to that of the sample prepared by the traditional sintering method, and its maximum ZT value reached 0.56 at 823 K. Moreover, a Ti-Co-Sb ternary compound transition layer of about 70 μm in thickness was found at a dense interface between CoSb 2.85 Te 0.15 and the Ti substrate. The contact resistivity was measured as 37.1 μΩcm 2 . The results demonstrate that SLM, coupled with postannealing, can be used for fabrication of incongruently melting skutterudite compounds on heterogeneous substrates. This lays an important foundation for the follow-up research utilizing energy efficient SHS and SLM processes in rapid printing of thermoelectric modules.

[Sb{sub 4}Au{sub 4}Sb{sub 4}]{sup 2−}: A designer all-metal aromatic sandwich

Energy Technology Data Exchange (ETDEWEB)

Tian, Wen-Juan; You, Xue-Rui [Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China); Guo, Jin-Chang [Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000 (China); Li, Da-Zhi, E-mail: hj.zhai@sxu.edu.cn, E-mail: ldz005@126.com [Department of Chemical Engineering, Binzhou University, Binzhou 256603 (China); Wang, Ying-Jin [Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China); Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000 (China); Sun, Zhong-Ming [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhai, Hua-Jin, E-mail: hj.zhai@sxu.edu.cn, E-mail: ldz005@126.com [Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China); State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006 (China)

2016-07-28

We report on the computational design of an all-metal aromatic sandwich, [Sb{sub 4}Au{sub 4}Sb{sub 4}]{sup 2−}. The triple-layered, square-prismatic sandwich complex is the global minimum of the system from Coalescence Kick and Minima Hopping structural searches. Following a standard, qualitative chemical bonding analysis via canonical molecular orbitals, the sandwich complex can be formally described as [Sb{sub 4}]{sup +}[Au{sub 4}]{sup 4−}[Sb{sub 4}]{sup +}, showing ionic bonding characters with electron transfers in between the Sb{sub 4}/Au{sub 4}/Sb{sub 4} layers. For an in-depth understanding of the system, one needs to go beyond the above picture. Significant Sb → Au donation and Sb ← Au back-donation occur, redistributing electrons from the Sb{sub 4}/Au{sub 4}/Sb{sub 4} layers to the interlayer Sb–Au–Sb edges, which effectively lead to four Sb–Au–Sb three-center two-electron bonds. The complex is a system with 30 valence electrons, excluding the Sb 5s and Au 5d lone-pairs. The two [Sb{sub 4}]{sup +} ligands constitute an unusual three-fold (π and σ) aromatic system with all 22 electrons being delocalized. An energy gap of ∼1.6 eV is predicted for this all-metal sandwich. The complex is a rare example for rational design of cluster compounds and invites forth-coming synthetic efforts.

DWPF SB6 Initial CPC Flowsheet Testing SB6-1 TO SB6-4L Tests Of SB6-A And SB6-B Simulants

International Nuclear Information System (INIS)

Lambert, D.; Pickenheim, B.; Best, D.

2009-01-01

The Defense Waste Processing Facility (DWPF) will transition from Sludge Batch 5 (SB5) processing to Sludge Batch 6 (SB6) processing in late fiscal year 2010. Tests were conducted using non-radioactive simulants of the expected SB6 composition to determine the impact of varying the acid stoichiometry during the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processes. The work was conducted to meet the Technical Task Request (TTR) HLW/DWPF/TTR-2008-0043, Rev.0 and followed the guidelines of a Task Technical and Quality Assurance Plan (TT and QAP). The flowsheet studies are performed to evaluate the potential chemical processing issues, hydrogen generation rates, and process slurry rheological properties as a function of acid stoichiometry. These studies were conducted with the estimated SB6 composition at the time of the study. This composition assumed a blend of 101,085 kg of Tank 4 insoluble solids and 179,000 kg of Tank 12 insoluble solids. The current plans are to subject Tank 12 sludge to aluminum dissolution. Liquid Waste Operations assumed that 75% of the aluminum would be dissolved during this process. After dissolution and blending of Tank 4 sludge slurry, plans included washing the contents of Tank 51 to ∼1M Na. After the completion of washing, the plan assumes that 40 inches on Tank 40 slurry would remain for blending with the qualified SB6 material. There are several parameters that are noteworthy concerning SB6 sludge: (1) This is the second batch DWPF will be processing that contains sludge that has had a significant fraction of aluminum removed through aluminum dissolution; (2) The sludge is high in mercury, but the projected concentration is lower than SB5; (3) The sludge is high in noble metals, but the projected concentrations are lower than SB5; and(4) The sludge is high in U and Pu - components that are not added in sludge simulants. Six DWPF process simulations were completed in 4-L laboratory-scale equipment using

The new Zintl phases Eu{sub 21}Cd{sub 4}Sb{sub 18} and Eu{sub 21}Mn{sub 4}Sb{sub 18}

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi; Darone, Gregory M.; Bobev, Svilen, E-mail: bobev@udel.edu

2016-06-15

Crystals of two new Zintl compounds, Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} have been synthesized using the molten metal flux method, and their structures have been established by single-crystal X-ray diffraction. Both compounds are isotypic and crystallize in the monoclinic space group C2/m (No. 12, Z=4). The structures are based on edge- and corner-shared MnSb{sub 4} or CdSb{sub 4} tetrahedra, which make octameric [Mn{sub 8}Sb{sub 22}] or [Cd{sub 8}Sb{sub 22}] polyanions. Homoatomic Sb–Sb bonds are present in both structures. The Eu atoms take the role of Eu{sup 2+}cations with seven unpaired 4f electrons, as suggested by the temperature-dependent magnetization measurements. The magnetic susceptibilities of Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} indicate that both phases order anti-ferromagnetically with Néel temperatures of ca. 7 K and ca. 10 K, respectively. The unpaired 3d electrons of the Mn atoms in Eu{sub 21}Mn{sub 4}Sb{sub 18} do contribute to the magnetic response, however, the bulk magnetization measurements do not provide evidence for long-range ordering of the Mn spins down to 5 K. Electrical resistivity measurements suggest that both compounds are narrow band gap semiconductors. - Graphical abstract: Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} have complex monoclinic structures, based on MnSb{sub 4} and CdSb{sub 4} tetrahedra, both edge- and corner-shared. A perspective of the crystal structure is shown, as viewed along the b axis. Display Omitted - Highlights: • Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} are novel compounds in the respective ternary phase diagrams. • For both structures, the Zintl-Klemm rules are followed, and both are small gap semiconductors. • Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} are air-stable Zintl phases and could be new thermoelectric materials.

Tests results of skutterudite based thermoelectric unicouples

International Nuclear Information System (INIS)

Saber, Hamed H.; El-Genk, Mohamed S.; Caillat, Thierry

2007-01-01

Tests were performed of skutterudite based unicouples with (MAY-04) and without (MAR-03) metallic coating on the legs near the hot junction to quantify the effect on reducing performance degradation with operation time. The p-legs in the unicouples were made of CeFe 3.5 Co 0.5 Sb 12 and the n-legs of CoSb 3 . The MAY-04 test was performed in vacuum (∼9 x 10 -7 torr) for ∼2000 h at hot and cold junction temperatures of 892.1 ± 11.9 K and 316.1 ± 5.5 K, respectively, while the MAR-03 test was performed in argon cover gas (0.051-0.068 MPa) at 972.61 ± 10.0 K and 301.1 ± 5.1 K, respectively. The argon cover gas decreased antimony loss from the legs in the MAR-03 test, but marked degradation in performance occurred over time. Conversely, the metallic coating in the MAY-04 test was very effective in reducing performance degradation of the unicouple. Because the cross sectional areas of the legs in MAY-04 were larger than those in MAR-03, the measured electrical power of the former is much higher than that of the latter, but the Beginning of Test (BOT) open circuit voltages, V oc (204.2 mV) for both unicouples were almost the same. The peak electrical power of the MAY-04 unicouple decreased 12.35% from 1.62W e at BOT to 1.42W e after ∼2000 h of testing, while that of the MAR-03 unicouple decreased 25.37% from 0.67 to 0.5W e after 261 h of testing at the above temperatures. The estimated peak efficiency of the MAY-04 unicouple, shortly after BOT (10.65%), was only ∼0.37% points lower than the theoretical value, calculated assuming zero side heat losses and zero contact resistance per leg

Ferromagnetic Instability in AFe4Sb12 (A = Ca, Sr, and Ba)

OpenAIRE

Matsuoka, E.; Hayashi, K.; Ikeda, A.; Tanaka, K.; Takabatake, T.; Higemoto, W.; Matsumura, M.

2004-01-01

Magnetic, transport and thermal properties of AFe4Sb12 (A = Ca, Sr, Ba) are reported. All three compounds show a maximum in both the magnetic susceptibility and thermopower at 50 K, and a large electronic specific heat coefficient of 100 mJ/mol K2. These properties are the characteristics of a nearly ferromagnetic metal. Furthermore, a remanent moment of the order of 10-3muB/Fe was observed below 54, 48, and 40 K for A = Ca, Sr, and Ba, respectively. The volume fraction of the ferromagnetic c...

Quasiparticle relaxation in Heavy Fermions studied using Inverse Fourier Transform of optical conductivity

International Nuclear Information System (INIS)

Dordevic, S.V.

2012-01-01

Inverse Fourier Transform of optical conductivity is used for studies of quasiparticle relaxation in Heavy Fermions in time domain. We demonstrate the usefulness of the procedure on model spectra and then use it to study quasiparticle relaxation in two Heavy Fermions YbFe 4 Sb 12 and CeRu 4 Sb 12 . Optical conductivity in time domain reveals details of quasiparticle relaxation close to the Fermi level, not readily accessible from the spectra in the frequency domain. In particular, we find that the relaxation of heavy quasiparticles does not start instantaneously, but typically after a few hundred femto-seconds.

Crystal structure, {sup 139}La NMR and transport properties of the As-based filled skutterudites LaOs{sub 4}As{sub 12} and PrOs{sub 4}As{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Wawryk, R.; Zogal, O.; Pietraszko, A.; Paluch, S.; Cichorek, T. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland); Yuhasz, W.M.; Sayles, T.A.; Ho, P.-C.; Yanagisawa, T.; Butch, N.P.; Maple, M.B. [Department of Physics and Institute for Pure and Applied Physical Sciences, University of California, San Diego (United States); Henkie, Z. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)], E-mail: Z.Henkie@int.pan.wroc.pl

2008-02-28

We have grown single crystals of LaOs{sub 4}As{sub 12} and PrOs{sub 4}As{sub 12}, which crystallize in the LaFe{sub 4}P{sub 12}-type structure (Im3-bar space group) with the lattice parameters of 8.542(1) A and 8.520(1) A, respectively. From a narrow {sup 139}La NMR line, we estimated an appreciable Knight shift ({sup 139}K) and a relatively long spin-lattice-relaxation time in the non-4f electron system LaOs{sub 4}As{sub 12}. Surprisingly, while {sup 139}K vary non-monotonically with temperature, the magnetic susceptibility increases upon cooling over the whole temperature range. Interestingly, the high-temperature dependence of the thermoelectric power of LaOs{sub 4}As{sub 12} is remarkably similar to that one of PrOs{sub 4}As{sub 12}.

Assembly of a new inorganic-organic frameworks based on [Sb4Mo12(OH)6O48]10- polyanion

Science.gov (United States)

Thabet, Safa; Ayed, Meriem; Ayed, Brahim; Haddad, Amor

2014-10-01

A new organic-inorganic hybrid material, (C4N2H7)8[K(H2O)]2[Sb4Mo12(OH)6O48]ṡ16H2O (1) has been isolated by the conventional solution method and characterized by elemental analysis, single-crystal X-ray diffraction, infrared spectroscopy, UV-visible spectroscopies, cyclic voltammetry and TG-DTA analysis. The compound crystallizes in the triclinic space group P - 1 with a = 13.407(6) Å, b = 13.906(2) Å, c = 14.657(7) Å, α = 77.216(9)°, β = 71.284(6)°, γ = 71.312(3)° and Z = 1. The crystal structure exhibits an infinite 1D inorganic structure built from [Sb4Mo12(OH)6O48]10- clusters and potassium cations; adjacent chains are further joined up hydrogen bonding interactions between protonated 2-methylimidazolim cations, water molecules and polyoxoanions to form a 3D supramolecular architecture.

Magnetic properties in the vortex state of Pr1-xNdxPt4Ge12 and PrPt3.88Fe0.12Ge12 superconductors

Science.gov (United States)

Chandra, L. S. Sharath; Chattopadhyay, M. K.

2018-03-01

We report the temperature and magnetic field dependence of magnetization of Pr1-xNdxPt4Ge12 (x = 0, 0.05 and 0.1) and PrPt3.88Fe0.12Ge12 below 10 K and up to 2 T magnetic field. When compared to the parent PrPt4Ge12, while the critical current density and flux pinning properties are enhanced in the Pr1-xNdxPt4Ge12 samples, they are considerably diminished in the PrPt3.88Fe0.12Ge12 sample. We argue that the observed changes are related to the way the substituting atoms at different crystallographic sites influence the superconductivity in these Germanide skutterudites.

Thermoelectric and mechanical properties of spark plasma sintered Cu3SbSe3 and Cu3SbSe4: Promising thermoelectric materials

Science.gov (United States)

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

2014-12-01

We report the synthesis of thermoelectric compounds, Cu3SbSe3 and Cu3SbSe4, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu3SbSe4 exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu3SbSe3, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu3SbSe4 was found to be ˜1.2 as compared to 0.2 V-1 for Cu3SbSe3 at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

Colligative thermoelectric transport properties in n-type filled CoSb3 determined by guest electrons in a host lattice

International Nuclear Information System (INIS)

Lim, Young Soo; Park, Kwan-Ho; Tak, Jang Yeul; Lee, Soonil; Seo, Won-Seon; Park, Cheol-Hee; Kim, Tae Hoon; Park, PumSuk; Kim, Il-Ho; Yang, Jihui

2016-01-01

Among many kinds of thermoelectric materials, CoSb 3 has received exceptional attention for automotive waste heat recovery. Its cage structure provides an ideal framework for the realization of phonon-glass electron-crystal strategy, and there have been numerous reports on the enhanced thermoelectric performance through the independent control of the thermal and electrical conductivity by introducing fillers into its cage sites. Herein, we report colligative thermoelectric transport properties in n-type CoSb 3 from the viewpoint of “guest electrons in a host lattice.” Both the Seebeck coefficient and the charge transport properties are fundamentally determined by the concentration of the guest electrons, which are mostly donated by the fillers, in the conduction band of the host CoSb 3 . Comparing this observation to our previous results, colligative relations for both the Seebeck coefficient and the mobility were deduced as functions of the carrier concentration, and thermoelectric transport constants were defined to predict the power factor in filled CoSb 3 . This discovery not only increases the degree of freedom for choosing a filler but also provides the predictability of power factor in designing and engineering the n-type filled CoSb 3 materials.

Tetrahedral 1B4Sb nanoclusters in GaP:(B, Sb)

Energy Technology Data Exchange (ETDEWEB)

Elyukhin, V A, E-mail: elyukhin@cinvestav.m [Departamento de Ingenieria Electrica-SEES, CINVESTAV-IPN, Avenida IPN 2508, Col. San Pedro Zacatenco, C. P. 07360, Mexico, D. F. (Mexico)

2009-05-01

Self-assembling conditions of 1B4Sb tetrahedral nanoclusters in GaP doped with boron and Sb isoelectronic impurities are represented in the ultradilute and dilute limits of the boron and Sb contents, respectively. The fulfilled estimates demonstrated the preferential complete or almost complete allocation of boron atoms in 1B4Sb nanoclusters at temperatures of 500 {sup 0}C and 900 {sup 0}C, respectively. The significant decrease of the sum of the free energies of the constituent compounds is the main origin of self-assembling. The reduction of the strain energy is the additional cause of this phenomenon.

Mössbauer and magnetic studies of Mg{sub 1+2x}Sb{sub x}Fe{sub 2−3x}O{sub 4} spinel ferrites

Energy Technology Data Exchange (ETDEWEB)

Widatallah, H.M., E-mail: hishammw@squ.edu.om [Department of Physics, College of Science, Sultan Qaboos University, 123 Muscat (Oman); Al-Mamari, F.A.S.; Al-Saqri, N.A.M.; Gismelseed, A.M.; Al-Omari, I.A.; Al-Shahumi, T.M.H. [Department of Physics, College of Science, Sultan Qaboos University, 123 Muscat (Oman); Alhaj, A.F. [Department of Physics, Qasim University, Al-Qasim (Saudi Arabia); Abo El Ata, A.M. [Department of Physics, Faculty of Science, Tanta University, Tanta (Egypt); Elzain, M.E. [Department of Physics, College of Science, Sultan Qaboos University, 123 Muscat (Oman)

2013-06-15

Spinel-related Mg{sub 1+2x}Sb{sub x}Fe{sub 2−3x}O{sub 4} samples (x = 0.0, 0.05, 0.10, 0.15, 0.20, and 0.30) prepared using the conventional double sintering technique were investigated using {sup 57}Fe Mössbauer spectroscopy and magnetic measurements. Mössbauer spectra favor a cationic distribution of the form (Mg{sub δ}Fe{sub 1−δ}){sup A}[Mg{sub 1+2x−δ}Sb{sub x}Fe{sub 1+δ−3x}]{sup B}O{sub 4} among the tetrahedral-A and octahedral-B sites of the spinel structure. The cation distribution parameter (δ) was found to vary with the Sb{sup 5+} concentration (x). The Mössbauer hyperfine magnetic fields at both sites and the Curie temperatures of the ferrites decrease as x increases. This was attributed to gradual weakening in the magnetic exchange interaction as more Fe{sup 3+} ions are substituted by diamagnetic Sb{sup 5+} and Mg{sup 2+} ones. The sample with x = 0.30 exhibits short range magnetic order due to cationic clustering and/or superparamagnetism. The magnetization of all samples was found to be temperature-dependent implying that δ depends on temperature in addition to x. At low temperatures the substituted ferrites (x ≠ 0.0) unexpectedly exhibit higher magnetization values relative to that of the pure ferrite MgFe{sub 2}O{sub 4}. This behavior, while at variance with the Néel's model for ferrimagnetism, is explicable in terms of the spin canting mechanism proposed in the Yafet–Kittel model. - Highlights: ► A Mössbauer and magnetic study of Sb{sup 5+} and Mg{sup 2+} co-substituted ferrites of the composition Mg{sub 1+2x}Sb{sub x}Fe{sub 2−3x}O{sub 4} is reported. ► The cation distribution in Mg{sub 1+2x}Sb{sub x}Fe{sub 2−3x}O{sub 4} is shown to depend on both the Sb{sup 5+} ionic concentration and the temperature. ► The A–B magnetic exchange interaction and Mössbauer hyperfine fields weaken with increasing Sb{sup 5+} and Mg{sup 2+} concentrations. ► The magnetization of the substituted samples with x ≠ 0.00 increases

Crystal structure and bonding characteristics of In-doped β-Zn4Sb3

International Nuclear Information System (INIS)

Tang, Dingguo; Zhao, Wenyu; Cheng, Sudan; Wei, Ping; Yu, Jian; Zhang, Qingjie

2012-01-01

The effects of indium impurity on the crystal structure and bonding characteristics of In-doped β-Zn 4 Sb 3 were investigated by powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD Rietveld refinement indicates that the indium impurity preferentially substitutes one of Sb atoms in Sb–Sb dimer at the 12c Sb(2) site and simultaneously leads to the increase of Zn occupancy. The observations of binding energy shift and a new valence state in Sb 3d core-level XPS spectra can be attributed to the charge transfer from In and Zn to Sb. As a result, more electropositive Zn atoms are needed to maintain the charge balance. The reduction of the lattice thermal conductivity is ascribed to the formation of the asymmetric Sb–In bond, resulting in much low lattice thermal conductivity of 0.49 W −1 K −1 of Zn 4 Sb 2.96 In 0.04 . - Graphical abstract: The indium impurity substitutes one of Sb atoms in Sb–Sb dimer, resulting the charge transfer from In to Sb, which leads to the binding energy of Sb 3d core level XPS spectra shift to low value. Highlights: ► The indium impurity preferentially substitutes one of Sb atoms in Sb–Sb dimer at the 12c Sb(2) site. ► The occupancy of Zn increases by the In substitution for Sb, whereas that of Sb keeps constant. ► The binding energy of Sb 3d shifts to low value. ► The charge transfer occurs from In and Zn to Sb.

Tests results and performance comparisons of coated and un-coated skutterudite based segmented unicouples

International Nuclear Information System (INIS)

El-Genk, Mohamed S.; Saber, Hamed H.; Caillat, Thierry; Sakamoto, Jeff

2006-01-01

Skutterudite based thermoelectric unicouples are being considered for use in Advanced Radioisotope Power Systems (ARPSs) to support NASA's planetary exploration missions. For these systems, which would be much lighter than state of the art Radioisotope Thermoelectric Generators (RTGs), it is important to ensure minimal degradation in the performance of unicouples that may be caused by material sublimation. In this work, two unicouples, JAN-04 with a thin metallic coating on the legs near the hot junction to suppress antimony sublimation and SEP-03 without coating, are tested for >1000 and 3600 h, respectively. The legs in the two unicouples are of almost the same dimensions and compositions; the p-legs are made of CeFe 3.5 Co 0.5 Sb 12 and Bi 0.4 Sb 1.6 Te 3 segments and the n-legs are made of CoSb 3 and Bi 2 Te 2.95 Se 0.05 segments. SEP-03 is tested at average hot and cold junction temperatures of 961.5 ± 22.0 and 296.3 ± 5.7 K, respectively, in argon gas at ∼0.068 MPa, and JAN-04 is tested at 962.8 ± 20.5 and 294.5 ± 3.3 K, respectively, initially in argon gas at the same pressure for ∼26.5 h then in vacuum ∼9.0 x 10 -7 Torr for >973.5 h. The measured open circuit voltage V oc (240 mV) and peak electrical power (1.64 W e ) for SEP-03 at the beginning of test (BOT) are higher than those for JAN-04 (188 mV and 0.84 W e , respectively). Although the argon gas effectively decreased the antimony loss from the legs of SEP-03, marked degradations in performance occurred. The estimated peak efficiency for SEP-03 decreased from 13.8% at BOT to 5.8% at end of test (EOT), and the peak power decreased from 1.64 W e at BOT to 0.48 W e at EOT, however, V oc decreased by ∼14%. The latter for JAN-04 decreased only by ∼3%, the estimated peak efficiency (∼12%) changed very little and the peak power decreased by ∼20%. Unlike SEP-03, the measured total and contact resistances of the legs in JAN-04 changed very little

Colligative thermoelectric transport properties in n-type filled CoSb{sub 3} determined by guest electrons in a host lattice

Energy Technology Data Exchange (ETDEWEB)

Lim, Young Soo, E-mail: yslim@pknu.ac.kr, E-mail: wsseo@kicet.re.kr, E-mail: pmoka@lgchem.com [Department of Materials System Engineering, Pukyong National University, Busan 48547 (Korea, Republic of); Park, Kwan-Ho; Tak, Jang Yeul; Lee, Soonil; Seo, Won-Seon, E-mail: yslim@pknu.ac.kr, E-mail: wsseo@kicet.re.kr, E-mail: pmoka@lgchem.com [Energy and Environmental Division, Korea Institute of Ceramic Engineering and Technology (KICET), Jinju 52851 (Korea, Republic of); Park, Cheol-Hee, E-mail: yslim@pknu.ac.kr, E-mail: wsseo@kicet.re.kr, E-mail: pmoka@lgchem.com; Kim, Tae Hoon; Park, PumSuk [LG Chem/Research Park, Daejeon 34122 (Korea, Republic of); Kim, Il-Ho [Department of Materials Science and Engineering, Korea National University of Transportation, Chungju 27909 (Korea, Republic of); Yang, Jihui [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States)

2016-03-21

Among many kinds of thermoelectric materials, CoSb{sub 3} has received exceptional attention for automotive waste heat recovery. Its cage structure provides an ideal framework for the realization of phonon-glass electron-crystal strategy, and there have been numerous reports on the enhanced thermoelectric performance through the independent control of the thermal and electrical conductivity by introducing fillers into its cage sites. Herein, we report colligative thermoelectric transport properties in n-type CoSb{sub 3} from the viewpoint of “guest electrons in a host lattice.” Both the Seebeck coefficient and the charge transport properties are fundamentally determined by the concentration of the guest electrons, which are mostly donated by the fillers, in the conduction band of the host CoSb{sub 3}. Comparing this observation to our previous results, colligative relations for both the Seebeck coefficient and the mobility were deduced as functions of the carrier concentration, and thermoelectric transport constants were defined to predict the power factor in filled CoSb{sub 3}. This discovery not only increases the degree of freedom for choosing a filler but also provides the predictability of power factor in designing and engineering the n-type filled CoSb{sub 3} materials.

Lead-free Perovskite Materials (NH4 )3 Sb2 Ix Br9-x.

Science.gov (United States)

Zuo, Chuantian; Ding, Liming

2017-06-01

A family of perovskite light absorbers (NH 4 ) 3 Sb 2 I x Br 9-x (0≤x≤9) was prepared. These materials show good solubility in ethanol, a low-cost, hypotoxic, and environmentally friendly solvent. The light absorption of (NH 4 ) 3 Sb 2 I x Br 9-x films can be tuned by adjusting I and Br content. The absorption onset for (NH 4 ) 3 Sb 2 I x Br 9-x films changes from 558 nm to 453 nm as x changes from 9 to 0. (NH 4 ) 3 Sb 2 I 9 single crystals were prepared, exhibiting a hole mobility of 4.8 cm 2  V -1  s -1 and an electron mobility of 12.3 cm 2  V -1  s -1 . (NH 4 ) 3 Sb 2 I 9 solar cells gave an open-circuit voltage of 1.03 V and a power conversion efficiency of 0.51 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of Ni impurities on the thermoelectric properties of Ca-partially filled skutterudites Ca.sub.x./sub.Co.sub.4./sub.Sb.sub.12./sub..

Czech Academy of Sciences Publication Activity Database

Puyet, M.; Lenoir, B.; Dauscher, A.; Candolfi, C.; Hejtmánek, Jiří; Stiewe, C.; Müller, E.

2012-01-01

Roč. 101, č. 22 (2012), "222105-1"-"222105-4" ISSN 0003-6951 Institutional research plan: CEZ:AV0Z10100521 Keywords : performance * barium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.794, year: 2012 http://apl.aip.org/

Possible nodal vortex state in CeRu2

International Nuclear Information System (INIS)

Kadono, R.; Higemoto, W.; Koda, A.; Ohishi, K.; Yokoo, T.; Akimitsu, J.; Hedo, M.; Inada, Y.; Onuki, Y.; Yamamoto, E.

2001-01-01

The microscopic property of magnetic vortices in the mixed state of a high-quality CeRu 2 crystal has been studied by muon spin rotation. We have found that the spatial distribution of magnetic induction B(r) probed by muons is perfectly described by the London model for the triangular vortex lattice with appropriate modifications to incorporate the high-field cutoff around the vortex core and the effect of long-range defects in the vortex lattice structure at lower fields. The vortex core radius is proportional to H (β-1)/2 with β≅0.53 (H being the magnetic field), which is in good agreement with the recently observed nonlinear field dependence of the electronic specific heat coefficient γ∝H β . In particular, the anomalous increase of magnetic penetration depth in accordance with the peak effect in dc magnetization (≥H * ≅3 T at 2.0 K) has been confirmed; this cannot be explained by the conventional pair-breaking effect due to magnetic field. In addition, the spontaneous enhancement of flux pinning, which is also associated with the peak effect, has been demonstrated microscopically. These results strongly suggest the onset of collective pinning induced by a new vortex state having an anomalously enhanced quasiparticle density of states for H≥H *

Thermoelectric and mechanical properties of spark plasma sintered Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}: Promising thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay, E-mail: adhar@nplindia.org [CSIR-Network of Institutes for Solar Energy, Materials Physics and Engineering, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

2014-12-29

We report the synthesis of thermoelectric compounds, Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu{sub 3}SbSe{sub 4} exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu{sub 3}SbSe{sub 3}, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu{sub 3}SbSe{sub 4} was found to be ∼1.2 as compared to 0.2 V{sup −1} for Cu{sub 3}SbSe{sub 3} at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

Coherent electron-correlation compatible with random atom stacking in amorphous Ce-Ru alloys

International Nuclear Information System (INIS)

Homma, Yoshiya; Sumiyama, Kenji; Yamauchi, Hiroshi; Suzuki, Kenji

1997-01-01

The amorphous Ce-Ru alloys produced by the sputtering technique show the following distinct behaviors at low temperatures. The electronic specific heat coefficient rapidly increases below 5 K for Ce-19 and 42 at.%Ru alloys with decreasing temperature, T, (a heavy fermion behavior). The electrical resistivity displays -logT dependence at T > 40 K (an incoherent or impurity Kondo effect). Is slightly decreases at T < 30 K for Ce-19 and 42 at.%Ru alloys (a coherent Kondo effect), while it abruptly decreases at 2.5 K for 82 at.%Ru (a superconducting phenomenon). These coherent states may originate from the strong mixing and correlation of 4f-electrons and conduction-electrons even in the random alloy system. (author)

Domain engineering of the metastable domains in the 4f-uniaxial-ferromagnet CeRu2Ga2B

Science.gov (United States)

Wulferding, D.; Kim, H.; Yang, I.; Jeong, J.; Barros, K.; Kato, Y.; Martin, I.; Ayala-Valenzuela, O. E.; Lee, M.; Choi, H. C.; Ronning, F.; Civale, L.; Baumbach, R. E.; Bauer, E. D.; Thompson, J. D.; Movshovich, R.; Kim, Jeehoon

2017-04-01

In search of novel, improved materials for magnetic data storage and spintronic devices, compounds that allow a tailoring of magnetic domain shapes and sizes are essential. Good candidates are materials with intrinsic anisotropies or competing interactions, as they are prone to host various domain phases that can be easily and precisely selected by external tuning parameters such as temperature and magnetic field. Here, we utilize vector magnetic fields to visualize directly the magnetic anisotropy in the uniaxial ferromagnet CeRu2Ga2B. We demonstrate a feasible control both globally and locally of domain shapes and sizes by the external field as well as a smooth transition from single stripe to bubble domains, which opens the door to future applications based on magnetic domain tailoring.

Peak effect studies in single crystals CeRu2 and 2H-NbS2

Indian Academy of Sciences (India)

vibrating sample magnetometer (VSM) (Oxford Instruments, UK) on single crystal sam- ples of CeRu2 and 2H-NbS2. All the measurements were carried out by cooling the sample in zero field (ZFC mode) and then by applying the magnetic field. The measurements were carried out with the magnetic field parallel to the cube ...

Evaporation of tetramers in Sb4n clusters and conditions for the formation of Sb2n+1 clusters

International Nuclear Information System (INIS)

Rayane, D.; Tribollet, B.; Broyer, M.; Melinon, P.; Cabaud, B.; Hoareau, A.

1989-01-01

Antimony clusters are produced by the inert gas condensation technique. They are found to be built from Sb 4 units. The fragmentation by evaporation of Sb 4 units is studied as a function of the excess energy in the cluster. By this way the binding energy of the Sb 4 units in the cluster is found to be about 1.5 eV, well below the binding energy of a Sb atom in the bulk and in Sb 4 (≅3 eV). The evolution of ionization potentials of Sb 4n clusters confirms that their structure is probably non metallic. Finally the possible metastable character of this Sb 4n structure is discussed. (orig.)

Giant dielectric response in (Sr, Sb) codoped CaCu3Ti4O12 ceramics: A novel approach

Science.gov (United States)

Pradhan, M. K.; Rao, T. Lakshmana; Karna, Lipsarani; Dash, S.

2018-04-01

The CaCu3Ti4O12 (CCTO) remains as the best material for practical applications due to its high dielectric constant. To improve further the dielectric properties of CCTO to several orders in magnitude, a novel approach is adopted by codoping of Sr, Sb ions. The ceramic samples were fabricated by the conventional solid state route. The structure, morphology and detail dielectric properties were investigated systematically. All the samples crystalizes in a cubic symmetry with Im-3 space group. Sr substituted in Ca site can effectively suppress the grain growth, achieving a fine grained ceramic structure; however the grain size decreased slightly as Sb concentration increased further; whereas the dielectric permittivity of the ceramics increased drastically. The giant dielectric response was considered to be closely related with a reduction in the potential barrier height at grain boundaries (GBs) supported by the reduction in the activation energy for the conduction process.

Raman spectra of the system TeCl4-SbCl5

International Nuclear Information System (INIS)

Brockner, W.; Demiray, A.F.

1980-01-01

Raman spectra of the solid and molten TeCl 4 . SbCl 5 addition compound and of some TeCl 4 -SbCl 5 mixtures have been recorded. Two modifications of the crystalline TeCl 4 -SbCl 5 compound have been found. The structure of the melt can be described by the equilibrium TeCl 3 + + SbCl 6 - reversible TeCl 4 + SbCl 5 lying on the left side. Mixtures with other stoichiometry contain the 1:1 adduct only and excess TeCl 4 or SbCl 5 , respectively. Such melts are built up by the ionic species TeCl 3 + and SbCl 6 - also and TeCl 4 or SbCl 5 according to stoichiometry. (author)

Formation of high-conductivity regions in SnO2-AOx (A - Ti4+, Zr4+, Sb3+, Sb5+) films exposed to ultraviolet radiation of H2

International Nuclear Information System (INIS)

Postovalova, G.G.; Roginskaya, Yu.E.; Zav'yalov, S.A.; Galyamov, B.Sh.; Klimasenko, N.L.

2000-01-01

Composition, structure and electron properties of SnO 2 films doped by Ti, Zr and Sb oxides were studied. The doped SnO 2 films were determined to contain nano-regions of SnO 2 base crystalline solid solutions and amorphous SnO 2 containing Sn 2+ or Sb 3+ ions and residing at the surface of crystallites or between them. These composition and structure peculiarities affect essentially both electron structure and electrical properties of films. Localized 5s-states of the conductivity range diffused boundary of amorphous SnO 2 partially filled with 5s-electrons of Sn 2+ or Sb 3+ ions serving as traps capture free electrons in the crystalline ranges and motivate high resistance of films [ru

75As-NQR study of the hybridization gap semiconductor CeOs4As12

International Nuclear Information System (INIS)

Yogi, M; Niki, H; Higa, N; Kawata, T; Sekine, C

2016-01-01

We performed an 75 As nuclear quadrupole resonance (NQR) measurement on CeOs 4 As 12 . The 75 As-NQR spectrum shape demonstrates that the Ce-site filling fraction of our high-pressure synthesized sample is close to unity. A presence of the c — f hybridization gap is confirmed from the temperature dependence of the nuclear spin-lattice relaxation rate 1/T 1 . An increase of 1/T 1 below ∼3 K indicates a development of the spin fluctuations. The 1/T 1 for CeOs 4 As 12 shows similar behavior as that for CeOs 4 Sb 12 with different magnitude of the c — f hybridization gap. An absence of phase transition in CeOs 4 As 12 may be caused by the increase of the c — f hybridization, which increases the gap magnitude and reduces the residual density of state inside the gap. (paper)

Crystallographic study of the intermediate compounds SbZn, Sb3Zn4 and Sb2Zn3

International Nuclear Information System (INIS)

Adjadj, Fouzia; Belbacha, El-djemai; Bouharkat, Malek; Kerboub, Abdellah

2006-01-01

The processes of development of semiconductor ceramics made up of bismuth, antimony and zinc often require during their preparation to know the nature of the involved phases. For that, it is always essential to refer to the diagrams of balance between phases of the binary systems or ternary. We presented in this work the study by X-rays diffraction relating to the intermediate compounds SbZn, Sb 3 Zn 4 and Sb 2 Zn 3 . The analysis by X-rays is often useful to give supplement the results of the other experimental methods

Neutron scattering study of Ce3Au3Sb4

International Nuclear Information System (INIS)

Kasaya, Mitsuo; Katoh, Kenichi; Kohgi, Masahumi; Osakabe, Toyotaka

1993-01-01

Rare-earth compounds with an Y 3 Au 3 Sb 4 -type crystal structure are semiconductors or semi-metals. Among them, Ce 3 Au 3 Sb 4 is a semiconductor with an activation energy of about 640 K and shows no magnetic order down to 1.5 K. The magnetic part of the specific heat for Ce 3 Au 3 Sb 4 obtained by subtracting the value for La 3 Au 3 Sb 4 from the total specific heat of Ce 3 Au 3 Sb 4 shows a broad peak at around 10 K, the origin of which is well explained by the crystalline-field splitting determined by neutron scattering. (author)

Sb{sup III} - Sb{sup V} Exchange Reaction in Hydrochloric: Acid Solutions; Echange Sb{sup III}-Sb{sup V} dans des Solutions d'Acide Chlorhydrique; Reaktsiya obmena Sb(III) - Sb(V) v rastvorakh khloristovodorodnoj kisloty; Intercambio Sb{sup III}-Sb{sup V} en Soluciones de HCl

Energy Technology Data Exchange (ETDEWEB)

Kambara, T.; Yamaguchi, K.; Yasuba, S. [Shizuoka University, Shizuoka City (Japan)

1965-10-15

The exchange reaction of Sb{sup III} - Sb{sup V} in solutions of low HCl concentrations was studied using {sup 124}Sb as a tracer. The effects of HCl concentrations and chemical forms of antimony on the exchange rate were investigated. The HCl concentrations of the antimony solutions ((Sb{sup III}) =(Sb{sup V}) = 6.8 x 10{sup -4}M) were changed from 0.8 to 4.0M and the half-time for the exchange was measured by plotting log (1 - F) versus time t to calculate the exchange rate assuming the second-ordet reaction. It was found that the exchange rate was sharply increased with the increase of HCl concentrations (at 25 Degree-Sign C, from 0.8 to 2.0M) and at 2.0M HCl concentration the rate reached the maximum, from which the rate was decreased with the increase of HCl concentrations (at 25 Degree-Sign C, from 2.0 to 4.0M). Two sorts of Sb{sup V} species were used for our investigations, i.e. one was used directly after the dilution of 10M HCl Sb{sup V} solution with water and the other was used after 24 hours standing at room temperature from the dilution. (The Sb{sup III} species were also kept standing after preparation from 10M HCl Sb{sup III} solution.) In both cases the maximum rates were found to exist at 2.0M HCl concentration. The rate R{sub 1} for the former (directly after dilution) was 4.5 x 10{sup -6} mole litre{sup -1} min{sup -1} and the rate R{sub 2} for the latter (24 hours standing) was 1.2 x 10{sup -}{sub 6} mole litre. Also the activation energy for these cases was found to be 12.2 kcal/mole and 19.1 kcal/mole. By spectrophotometric studies, the Sb{sup V} species of the former type were found to be mainly consisting of SbCl{sup -}{sub 6} and the species of the latter type to be of SbCl{sub 4}(OH){sup -}{sub 2}, etc. Besides these facts the form of Sb{sup III} species was found to have no influence on the exchange rate. A much sharper increase of the exchange rate was observed when the HCl concentration of the antimony solution was fixed at 0.8M and

Sorghum phytochrome B inhibits flowering in long days by activating expression of SbPRR37 and SbGHD7, repressors of SbEHD1, SbCN8 and SbCN12.

Directory of Open Access Journals (Sweden)

Shanshan Yang

Full Text Available Light signaling by phytochrome B in long days inhibits flowering in sorghum by increasing expression of the long day floral repressors PSEUDORESPONSE REGULATOR PROTEIN (SbPRR37, Ma1 and GRAIN NUMBER, PLANT HEIGHT AND HEADING DATE 7 (SbGHD7, Ma6. SbPRR37 and SbGHD7 RNA abundance peaks in the morning and in the evening of long days through coordinate regulation by light and output from the circadian clock. 58 M, a phytochrome B deficient (phyB-1, ma3R genotype, flowered ∼60 days earlier than 100 M (PHYB, Ma3 in long days and ∼11 days earlier in short days. Populations derived from 58 M (Ma1, ma3R, Ma5, ma6 and R.07007 (Ma1, Ma3, ma5, Ma6 varied in flowering time due to QTL aligned to PHYB/phyB-1 (Ma3, Ma5, and GHD7/ghd7-1 (Ma6. PHYC was proposed as a candidate gene for Ma5 based on alignment and allelic variation. PHYB and Ma5 (PHYC were epistatic to Ma1 and Ma6 and progeny recessive for either gene flowered early in long days. Light signaling mediated by PhyB was required for high expression of the floral repressors SbPRR37 and SbGHD7 during the evening of long days. In 100 M (PHYB the floral activators SbEHD1, SbCN8 and SbCN12 were repressed in long days and de-repressed in short days. In 58 M (phyB-1 these genes were highly expressed in long and short days. Furthermore, SbCN15, the ortholog of rice Hd3a (FT, is expressed at low levels in 100 M but at high levels in 58 M (phyB-1 regardless of day length, indicating that PhyB regulation of SbCN15 expression may modify flowering time in a photoperiod-insensitive manner.

Evaluation of Thermoelectric Performance and Durability of Functionalized Skutterudite Legs

Science.gov (United States)

Skomedal, Gunstein; Kristiansen, Nils R.; Sottong, Reinhard; Middleton, Hugh

2017-04-01

Thermoelectric generators are a promising technology for waste heat recovery. As new materials and devices enter a market penetration stage, it is of interest to employ fast and efficient measurement methods to evaluate the long-term stability of thermoelectric materials in combination with metallization and coating (functionalized thermoelectric legs). We have investigated a method for measuring several thermoelectric legs simultaneously. The legs are put under a common temperature gradient, and the electrical characteristics of each leg are measured individually during thermal cycling. Using this method, one can test different types of metallization and coating applied to skutterudite thermoelectric legs and look at the relative changes over time. Postcharacterization of these initial tests with skutterudite legs using a potential Seebeck microprobe and an electron microscope showed that oxidation and interlayer diffusion are the main reasons for the gradual increase in internal resistance and the decrease in open-circuit voltage. Although we only tested skutterudite material in this work, the method is fully capable of testing all kinds of material, metallization, and coating. It is thus a promising method for studying the relationship between failure modes and mechanisms of functionalized thermoelectric legs.

Treatment for GaSb surfaces using a sulphur blended (NH4)2S/(NH4)2SO4 solution

International Nuclear Information System (INIS)

Murape, D.M.; Eassa, N.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

2012-01-01

A sulphur based chemical, [(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na 2 S·9H 2 O and (NH 4 ) 2 S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) than with (NH 4 ) 2 S or Na 2 S·9H 2 O, as evidenced by the ratio of the O 506eV to Sb 457eV AES peaks. XPS results reveal that Sb 2 S 3 /Sb 2 S 5 “replaces” Sb 2 O 3 /Sb 2 O 5 , suggesting that sulphur atoms substitute oxygen atoms in Sb 2 O 3 /Sb 2 O 5 to form Sb-S. It seems sulphurization only partially removes Ga 2 O 3 . Treatment with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

Non-Fermi-Liquid Behavior in CeRu2Si2 at Ultralow Temperatures Studied by Thermal Expansion and Magnetostriction

Science.gov (United States)

Inoue, Daiki; Takama, Hiroyuki; Kaidou, Daisuke; Minegishi, Mitsuyuki; Ueno, Keisuke; Matsumoto, Koichi; Abe, Satoshi; Murayama, Shigeyuki

2017-12-01

We report the linear thermal expansion and magnetostriction of the heavy-fermion compound CeRu2Si2 along its a- and c-axes at temperatures down to 10 mK and in magnetic fields up to 9 T using a high-precision capacitive dilatometer. From the magnetostriction measurements, a large anisotropy between values for the coefficient of magnetostriction along the a- and c-axes was found in the Landau-Fermi-liquid (LFL) state. Non-Fermi-liquid (NFL) behavior was observed for both the linear thermal expansion below 60 mK for all applied magnetic fields and the linear magnetostriction below 0.5 T and 300 mK. The results suggest the existence of an additional pressure-driven quantum critical point (QCP), and a crossover from the NFL state to the LFL state occurs in CeRu2Si2 at ambient pressure near the QCP.

Unprecedented connection mode of [V{sub 16}Sb{sub 4}O{sub 42}(H{sub 2}O)]{sup 8-} cluster anions by Mn{sup 2+} centered complexes. Solvothermal synthesis and properties of {[Mn(teta)]_4V_1_6Sb_4O_4_2(H_2O)}{sub n}.[(H{sub 2}O){sub 12}]{sub n}

Energy Technology Data Exchange (ETDEWEB)

Rasmussen, Maren; Naether, Christian; Bensch, Wolfgang [Institute of Inorganic Chemistry, Christian-Albrechts-University of Kiel (Germany); Leusen, Jan van; Koegerler, Paul [Institute of Inorganic Chemistry, RWTH Aachen University, Aachen (Germany)

2017-11-17

The new compound {[Mn(teta)]_4V_1_6Sb_4O_4_2}{sub n}.[(H{sub 2}O){sub 12}]{sub n} (teta = triethylenetetraamine) was synthesized under solvothermal conditions. The crystal structure features the high nuclearity [V{sub 16}{sup IV}Sb{sub 4}{sup III}O{sub 42}(H{sub 2}O)]{sup 8-} cluster anion, which consists of two rings composed of 8 edge-sharing VO{sub 5} polyhedra. The rings are perpendicular to each other generating four niches, which are occupied by two VO{sub 5} pyramids and two handle-like Sb{sub 2}O{sub 5} units. The two unique anions are each surrounded by eight Mn{sup 2+} centered complexes via Mn-O{sub term}-V bonds. Such an expansion has never been observed in heterometal polyoxovanadate chemistry. The connection mode between cluster anions and complex cations generates two individual layers stacked onto each other. Between the layers weak Sb..O contacts are observed. The crystal water molecules are mainly located in the empty space between the layers. Upon heating H{sub 2}O molecules are removed, while the crystal structure remains intact. The magnetic behavior is dominated by strong antiferromagnetic exchange interactions between the central V{sup 4+} ions, while the interaction between the cluster anion and central Mn{sup 2+} ions is significantly less pronounced. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Thermal conductivity of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} solid solutions

Energy Technology Data Exchange (ETDEWEB)

Caillat, T; Borshchevsky, A; Fleurial, J P

1997-07-01

{beta}-Zn{sub 4}Sb{sub 3} was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy {beta}-Zn{sub 4}Sb{sub 3} with isostructural compounds because of the expected decrease in lattice thermal conductivity. The authors have grown Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} crystals with 0.2 {le} x < 1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} alloys are significantly lower than those measured for {beta}-Zn{sub 4}Sb{sub 3} and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

Ga-Ga bonding and tunnel framework in the new Zintl phase Ba{sub 3}Ga{sub 4}Sb{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Park, S -M; Kim, S -J; Kanatzidis, M G

2003-11-01

A new Zintl phase Ba{sub 3}Ga{sub 4}Sb{sub 5} was obtained from the reaction of Ba and Sb in excess Ga flux at 1000 deg. C, and its structure was determined with single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group Pnma (No. 62) with a=13.248(3) A, b=4.5085(9) A, c=24.374(5) A and Z=4. Ba{sub 3}Ga{sub 4}Sb{sub 5} has a three-dimensional [Ga{sub 4}Sb{sub 5}]{sup 6-} framework featuring large tunnels running along the b-axis and accommodating the Ba ions. The structure also has small tube-like tunnels of pentagonal and rhombic cross-sections. The structure contains ethane-like dimeric Sb{sub 3}Ga-GaSb{sub 3} units and GaSb{sub 4} tetrahedra that are connected to form 12- and 14-membered tunnels. Band structure calculations confirm that the material is a semiconductor and indicate that the structure is stabilized by strong Ga-Ga covalent bonding interactions.

Analysis of the 4d9-(4d86p + 4p54d10) transitions of Sb VII and the strongest transitions of the 4d9-4d84f array of Sb VII and Te VIII

International Nuclear Information System (INIS)

Kildiyarova, R.R.; Churilov, S.S.; Joshi, Y.N.; Ryabtsev, A.N.

1995-01-01

The spectra of antimony and tellurium were photographed in the 100-200 A region on grazing incidence spectrographs at Moscow, Russia and NIST, U.S.A. laboratories. The 4d 9 -[4d 8 6p + 4p 5 4d 10 ] transition array of Sb VII was analyzed. 31 levels in Sb VII were established. 41 new lines in Sb VII belonging to the 4d 9 -(4p 5 4d 10 + 4d 8 6p) transition array have been classified. Seven lines each in Sb VII and Te VIII belonging to the 4d 9 -4d 8 4f transition array have been classified. Parametric least-squares-fitted calculations involving configuration interaction have been carried out to interpret the spectrum satisfactorily. (orig.)

Electric Properties of Pb(Sb1/2Nb1/2)O3 PbTiO3 PbZrO3 Ceramics

Science.gov (United States)

Kawamura, Yasushi; Ohuchi, Hiromu

1994-09-01

Solid-solution ceramics of ternary system xPb(Sb1/2Nb1/2)O3 yPbTiO3 zPbZrO3 were prepared by the solid-state reaction of powder materials. Ceramic, electric, dielectric and piezoelectric properties and crystal structures of the system were studied. Sintering of the system xPb(Sb1/2Nb1/2)O3 yPbTiO3 zPbZrO3 is much easier than that of each end composition, and well-sintered high-density ceramics were obtained for the compositions near the morphotropic transformation. Piezoelectric ceramics with high relative dielectric constants, high radial coupling coefficient and low resonant resistance were obtained for the composition near the morphotropic transformation. The composition Pb(Sb1/2Nb1/2)0.075Ti0.45Zr0.475O3 showed the highest dielectric constant (ɛr=1690), and the composition Pb(Sb1/2Nb1/2)0.05Ti0.45Zr0.5O3 showed the highest radial coupling coefficient (kp=64%).

Preparation and thermoelectric properties of RF co-sputtered CoSb{sub 3} skutteruddite thin films

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Aziz [University of Science and Technology, Daejeon (Korea, Republic of); Han, Seungwoo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); University of Science and Technology, Daejeon (Korea, Republic of)

2014-11-15

Various skutterudites have been under investigation because of their potential application in thermoelectric materials and devices. These studies indicate that bulk materials with a skutterudite type structure show reasonable thermoelectric behaviors at elevated temperatures, which make them suitable for high-temperature thermoelectric applications. The results of thermoelectric-property measurements on skutterudite-phase CoSb{sub 3} thin films are presented in this study in order to extend the bulk material concept to micro-device applications by using thin film deposition technology. Thin films are deposited on oxidized silicon substrates by using the RF co-sputtering method. The film's composition is found to depend strongly on the deposition conditions. The temperature at which the deposited films transition from an amorphous state to a crystalline state has been reported to be about 153 .deg. C. Therefore, some experiments are performed with the substrate temperature kept at 200 .deg. C to obtain polycrystalline films. The crystal structure of the film is evaluated by using x-ray diffraction (XRD) measurements. Energy dispersive spectroscopy (EDS) is used to determine the film's composition whereas the surface morphology and the thickness are investigated and measured by using scanning electron microscopy (SEM). Finally, the thermoelectric properties, namely, the electrical resistivity and the Seebeck coefficient, are used to calculate the power factor of the deposited thin films and, their variations with temperature are measured. We report a maximum power factor of 0.41 mW/mK{sup 2} for the film deposited at a 200 .deg. C substrate temperature.

Measurement setup for the simultaneous determination of diffusivity and Seebeck coefficient in a multi-anvil apparatus.

Science.gov (United States)

Jacobsen, M K; Liu, W; Li, B

2012-09-01

In this paper, a high pressure setup is presented for performing simultaneous measurements of Seebeck coefficient and thermal diffusivity in multianvil apparatus for the purpose of enhancing the study of transport phenomena. Procedures for the derivation of Seebeck coefficient and thermal diffusivity/conductivity, as well as their associated sources of errors, are presented in detail, using results obtained on the filled skutterudite, Ce(0.8)Fe(3)CoSb(12,) up to 12 GPa at ambient temperature. Together with recent resistivity and sound velocity measurements in the same apparatus, these developments not only provide the necessary data for a self-consistent and complete characterization of the figure of merit of thermoelectric materials under pressure, but also serve as an important tool for furthering our knowledge of the dynamics and interplay between these transport phenomena.

Crystal structure, chemical bond and enhanced performance of β-Zn4Sb3 compounds with interstitial indium dopant

International Nuclear Information System (INIS)

Tang, Dingguo; Zhao, Wenyu; Yu, Jian; Wei, Ping; Zhou, Hongyu; Zhu, Wanting; Zhang, Qingjie

2014-01-01

Highlights: • The interstitial In dopant leads to the local structural perturbations in β-Zn 4 Sb 3 . • The simultaneous increases in α and σ are observed in the In-doped Zn 4 Sb 3 compounds. • The In dopant plays different doping behaviors by the dopant contents in the samples. • A maximum ZT of 1.41 at 700 K is achieved for the In-doped Zn 4 Sb 3 compounds. - Abstract: In-doped β-Zn 4 Sb 3 compounds (Zn 4−x In x Sb 3 , 0 ⩽ x ⩽ 0.24) were prepared by melt-quenching and spark plasma sintering technology in the work. The resultant samples were systematically investigated by X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry and thermoelectric property measurements. The In dopant was identified to preferentially occupy the interstitial site in β-Zn 4 Sb 3 and led to the local structural perturbations near the 12c Sb2 and 36f Zn1 sites. The Auger parameters of Zn and Sb indicated that the increase in the valence of Zn was attributed to the charge transfer from Zn to In atoms. The binding energies of In 3d 5/2 core level showed that the interstitial In dopant was n-type dopant (In 3+ ) in slightly In-doped Zn 4−x In x Sb 3 , but acted as acceptor and was p-type dopant (In + ) in heavily In-doped ones. The discovery provides a reasonable explanation for the puzzled relation between σ and x for Zn 4−x In x Sb 3 . Simultaneously increasing the electrical conductivity and Seebeck coefficient of Zn 4−x In x Sb 3 can be realized through the local structural perturbations. The significantly enhanced power factor and the intrinsic low thermal conductivity resulted in a remarkable increase in the dimensionless figure of merit (ZT). The highest ZT reached 1.41 at 700 K for Zn 3.82 In 0.18 Sb 3 and increased by 68% compared with that of the undoped β-Zn 4 Sb 3

InAsSb for IR detection at 12 μm

International Nuclear Information System (INIS)

Dawson, L.R.

1989-01-01

The authors report the molecular beam epitaxial (MBE) growth of InAsSb alloys and superlattices on InSb substrates with intervening buffer layers designed to provide a lattice match to the SLS. Efficient incorporation of As is achieved by using an As 2 (thermally cracked) source in conjunction with an Sb 2 source at growth temperature of 425-450 0 C. At these temperatures desorption of excess Sb from the surface is limited and careful control of the Sb:In ratio is required. Even though the growth temperature is quite near the melting point of the alloys involved (525-550 0 C), TEM reveals abrupt, planar interfaces in superlattices with layer thicknesses less than 150 A. Undoped InSb layers are very pure, with n(77K) -- 1 x 10 14 cm -3 and μ(77K) --280,000 cm 2 V -1 sec -1 . Doping is easily controlled up to -- 10 18 using Be and PbSe. The entire structure (buffer plus SLS) is in tension with respect to the parent substrate, leading to extensive cracking for conventional buffer layers. More complex buffers, designed to more effectively relax the material to its equilibrium lattice constant, are used to solve this cracking problem. InAsSb SLSs grown on such buffer layers are crack-free and show marked reduction in dislocation density relative to that of the buffer layer. FTIR measurements made on SLSs with different compositions and differing amounts of strain in the active regions show optical absorption that is strain-shifted to wavelengths beyond λ c for bulk alloys, with substantial absorption beyond 12 μm

Are Sb4n (n>1) clusters weakly interacting tetrahedra?

International Nuclear Information System (INIS)

Kumar, V.

1993-03-01

The electronic and atomic structure of Sb 4 and Sb 8 clusters is studied using the ab-initio molecular dynamics method in the local density approximation. While for Sb 4 we obtain a regular tetrahedron to be about 2.0 eV lower in energy than a bent rhombus, for Sb 8 two structures, (1) two weakly interaction tetrahedra and (2) a bent rhombus interacting with a stretched tetrahedron, obtained from the simulated annealing lie only within about 0.1 eV indicating the importance of the bent rhombus structure for larger clusters. As compared to two isolated tetrahedra, the binding energy of Sb 8 is about 0.5 eV. Our results are thus in excellent agreement with the experimental data which show predominantly the abundance of tetramers above room temperature. (author). 18 refs, 5 figs, 1 tab

Hydrothermal synthesis, structure, and catalytic properties of UO2Sb2O4

International Nuclear Information System (INIS)

Sykora, Richard E.; King, Joseph E.; Illies, Andreas J.; Albrecht-Schmitt, Thomas E.

2004-01-01

A new uranyl antimonite, UO 2 Sb 2 O 4 (1), has been prepared from the hydrothermal reaction of UO 3 with Sb 2 O 3 and KCl. The structure of 1 consists of neutral two-dimensional ∞ 2 [UO 2 Sb 2 O 4 ] layers. The U(VI) centers are ligated by two trans oxo ligands and four square pyramidal antimonite anions. In addition, the U(VI) also forms long contacts with two additional oxygen atoms that are distorted by 12.7(2) degree sign out of the equatorial plane perpendicular to the uranyl unit. These long interactions are significant owing to evidence supplied by bond valence sum calculations. The two-dimensional layers found in 1 are built from one-dimensional chains formed from edge-sharing UO 6 octahedra that run along the b-axis, and are linked together by [Sb 2 O 4 ] 2- chains. A flow microreactor system has been used to study the catalytic activity of 1, and these results show that it can be used as a catalyst in the conversion of propene and O 2 to acrolein. Crystallographic data: 1, monoclinic, space group C2/m, a=13.490(2) A, b=4.0034(6) A, c=5.1419(8) A, β=104.165(3) deg., Z=2, MoKα, λ=0.71073, R(F)=1.74% for 30 parameters with 365 reflections with I>2σ(I)

Three-Dimensional Reduced Graphene Oxide Coupled with Mn3O4 for Highly Efficient Removal of Sb(III) and Sb(V) from Water.

Science.gov (United States)

Zou, Jian-Ping; Liu, Hui-Long; Luo, Jinming; Xing, Qiu-Ju; Du, Hong-Mei; Jiang, Xun-Heng; Luo, Xu-Biao; Luo, Sheng-Lian; Suib, Steven L

2016-07-20

Highly porous, three-dimensional (3D) nanostructured composite adsorbents of reduced graphene oxides/Mn3O4 (RGO/Mn3O4) were fabricated by a facile method of a combination of reflux condensation and solvothermal reactions and systemically characterized. The as-prepared RGO/Mn3O4 possesses a mesoporous 3D structure, in which Mn3O4 nanoparticles are uniformly deposited on the surface of the reduced graphene oxide. The adsorption properties of RGO/Mn3O4 to antimonite (Sb(III)) and antimonate (Sb(V)) were investigated using batch experiments of adsorption isotherms and kinetics. Experimental results show that the RGO/Mn3O4 composite has fast liquid transport and superior adsorption capacity toward antimony (Sb) species in comparison to six recent adsorbents reported in the literature and summarized in a table in this paper. Theoretical maximum adsorption capacities of RGO/Mn3O4 toward Sb(III) and Sb(V) are 151.84 and 105.50 mg/g, respectively, modeled by Langmuir isotherms. The application of RGO/Mn3O4 was demonstrated by using drinking water spiked with Sb (320 μg/L). Fixed-bed column adsorption experiments indicate that the effective breakthrough volumes were 859 and 633 mL bed volumes (BVs) for the Sb(III) and Sb(V), respectively, until the maximum contaminant level of 5 ppb was reached, which is below the maximum limits allowed in drinking water according to the most stringent regulations. The advantages of being nontoxic, highly stable, and resistant to acid and alkali and having high adsorption capacity toward Sb(III) and Sb(V) confirm the great potential application of RGO/Mn3O4 in Sb-spiked water treatment.

Preparation and crystal structure of Ca4Sb2O

International Nuclear Information System (INIS)

Eisenmann, B.; Limartha, H.; Schaefer, H.

1980-01-01

The formerly described compound Ca 2 Sb is to be corrected to Ca 4 Sb 2 O as shown by X-ray diffractometer data of single crystals and neutron diffraction diagrams of powders. The compound crystallizes in the K 2 NiF 4 structure type. (orig.)

TANK 40 FINAL SB4 CHEMICAL CHARACTERIZATION RESULTS

International Nuclear Information System (INIS)

Best, J.

2008-01-01

A sample of Sludge Batch 4 (SB4) was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). This sample was also analyzed for elemental and chemical composition including noble metals. These analyses along with the WAPS analyses will help define the composition of the sludge currently in Tank 40 which is currently being fed to DWPF and will become part of Sludge Batch 5 (SB5). At SRNL the 3-L Tank 40 SB4 sample was transferred from the shipping container into a 4-L vessel and solids allowed to settle overnight. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 280 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO 3 /HCl in sealed Teflon(reg s ign) vessels and four in Na 2 O 2 using Zr crucibles. Due to the use of Zr crucibles and Na in the peroxide fusions, Na and Zr cannot be determined from this preparation. Three glass standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted and submitted to Analytical Development (AD) for inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma-mass spectrometry (ICP-MS) analysis, and cold vapor atomic absorption (CV-AA) analysis. Equivalent dilutions of the peroxide fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB4 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES and ICP-MS. Weighted dilutions of slurry were submitted for ion chromatography (IC), total inorganic carbon/total organic carbon (TIC/TOC), and total base analyses. A sample of Tank 40 SB4 decant was collected by carefully removing the supernate phase

Frit Development Efforts for Sludge Batch 4 (SB4): Operating Window Assessments of Scenarios Leading Up to the Selected Preparation Plan for SB4

International Nuclear Information System (INIS)

Peeler, D

2006-01-01

The objective of this report is to document technical information that has been provided to Defense Waste Processing Facility (DWPF) and Closure Business Unit (CBU) personnel as part of the frit development support for Sludge Batch 4 (SB4). The information presented in this report includes projected operating windows (expressed in terms of waste loading) for various sludge blending and/or washing options coupled with candidate frits of interest. Although the Nominal Stage assessment serves as the primary tool for these evaluations, select systems were also evaluated using a Variation Stage assessment in which compositional variations were introduced. In addition, assessments of the impacts of nepheline formation potential and the SO 4 - solubility limit on the projected operating windows are also provided. Although this information was used as part of the technical basis leading to CBU's development of the preferred SB4 preparation plan, none of the options presented in this report was selected as the preferred plan. Therefore, the information is presented without significant interpretation of the resulting operating windows, but the projected windows are provided so additional insight can be explored if desired. Detailed assessments of the projected operating windows (using both Nominal and Variation Stage assessments) of the preferred sludge preparation plan with candidate frits are to be documented elsewhere. The information provided in this report is focused solely on model-based projections of the operating windows for various SB4 blending strategies of interest. Although nepheline formation potential is monitored via model predictions as a part of this assessment, experimental work investigating the impact of nepheline on glass quality is also being addressed in a parallel study. The results of this paper study and the experimental assessments of melt rate, SO 4 solubility, and/or nepheline formation potential are all critical components of the inputs into

Adducts of UF5 with SbF5 and structure of UF5 . 2SbF5

International Nuclear Information System (INIS)

Sawodny, W.; Rediess, K.

1980-01-01

Both α-UF 5 and β-UF 5 form only a 1:2 compound UF 5 . 2SbF 5 reacting directly with SbF 5 , from which UF 5 . SbF 5 can be obtained by thermal decomposition. UF 5 . 2SbF 5 crystallizes in the monoclinic space group P2 1 /c with the following lattice constants a = 8.110(4), b = 14.129(6), c = 10.032(6) A and β = 96.97(5) 0 ; Z = 4. An X-ray study shows centrosymmetric four-membered rings of alternating UF 8 and SbF 6 polyhedra connected by other SbF 6 entities. This structure is similar to that of UOF 5 . 2SbF 5 , but the distorted pentagonal-bipyramidal coordination of the U atom found there is increased to a dodecahedral coordination by an additional U-F-Sb bridge, though with a somewaht larger UF distance. (author)

Scanning thermal microscopy of Bi{sub 2}Te{sub 3} and Yb{sub 0.19}Co{sub 4}Sb{sub 12} thermoelectric films

Energy Technology Data Exchange (ETDEWEB)

Zeipl, Radek; Remsa, Jan; Kocourek, Tomas [Institute of Physics ASCR v.v.i., Prague (Czech Republic); Jelinek, Miroslav [Institute of Physics ASCR v.v.i., Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Vanis, Jan [Institute of Physics ASCR v.v.i., Prague (Czech Republic); Institute of Photonics and Electronics ASCR v.v.i., Prague (Czech Republic); Navratil, Jiri [Institute of Macromolecular Chemistry ASCR v.v.i., Prague (Czech Republic)

2016-04-15

Thermal conductivity of thermoelectric Bi{sub 2}Te{sub 3} and Yb{sub 0.19}Co{sub 4}Sb{sub 12} thin nanolayers of different thicknesses prepared by pulsed laser deposition on Si (100) substrates was studied by a scanning thermal microscope working in AC current pulse mode. A sensitivity of the approach is demonstrated on the steep Si substrate-layer boundary made by a Ga+ focused ion beam technique. Transport and thermoelectric properties such as in-plane electrical resistivity and the Seebeck coefficient were studied in temperature range from room temperature up to 200 C. The room temperature thermal conductivity of the layers was estimated from thermoelectric figure of merit that was measured by the Harman technique, in which parameters related to electrical conductivity, Seebeck coefficient and thermal conductivity are measured at the same place and at the same time with electrical current flowing through the layer. For Yb{sub 0.19}Co{sub 4}Sb{sub 12} and Bi{sub 2}Te{sub 3} layers, we observed room temperature electrical resistivity of about 7 and 1 mΩcm, the Seebeck coefficient of -112 and -61μVK{sup -1}, thermoelectric figure of merit about 0.04 and 0.13 and we estimated thermal conductivity of about 1.3 and 0.9 WK{sup -1}m{sup -1}, respectively. (orig.)

Low-temperature synthesis of single-phase Co7Sb2O12

International Nuclear Information System (INIS)

Brito, M.S.L.; Escote, M.T.; Santos, C.O.P.; Lisboa-Filho, P.N.; Leite, E.R.; Oliveira, J.B.L.; Gama, L.; Longo, E.

2004-01-01

Polycrystalline Co 7 Sb 2 O 12 compounds have been synthesized by a chemical route, which is based on a modified polymeric precursor method. In order to study the physical properties of the samples, X-ray diffraction (XRD), thermal analyses (TG and DSC), infrared spectroscopy (IR), specific surface area (BET), and magnetization measurements were performed on these materials. Characterization through XRD revealed that the samples are single-phase after a heat-treatment at 1100 deg. C for 2 h, while the X-ray patterns of the samples heat-treated at lower temperatures revealed the presence of additional Bragg reflections belonging to the Co 6 Sb 2 O 6 phase. These data were analyzed by means of Rietveld refinement and further analyze showed that Co 7 Sb 2 O 12 displays an inverse spinel crystalline structure. In this structure, the Co 2+ ions occupy the eight tetrahedral positions, and the sixteen octahedral positions are randomly occupied by the Sb 5+ and Co 2+ ions. IR studies disclosed two strong absorption bands, ν 1 and ν 2 , in the expected spectral range for a spinel-type binary oxide with space group Fd3m. Exploratory studies concerning the magnetic properties indicated that this sample presents a spin-glass transition at T f ∼ 64 K

First-principles study of amorphous Ga4Sb6Te3 phase-change alloys

Science.gov (United States)

Bouzid, Assil; Gabardi, Silvia; Massobrio, Carlo; Boero, Mauro; Bernasconi, Marco

2015-05-01

First-principles molecular dynamics simulations within the density functional theory framework were performed to generate amorphous models of the Ga4Sb6Te3 phase change alloy by quenching from the melt. We find that Ga-Sb and Ga-Te are the most abundant bonds with only a minor amount of Sb-Te bonds participating to the alloy network. Ga and four-coordinated Sb atoms present a tetrahedral-like geometry, whereas three-coordinated Sb atoms are in a pyramidal configuration. The tetrahedral-like geometries are similar to those of the crystalline phase of the two binary compounds GaTe and GaSb. A sizable fraction of Sb-Sb bonds is also present, indicating a partial nanoscale segregation of Sb. Despite the fact that the composition Ga4Sb6Te3 lies on the pseudobinary Ga Sb -Sb2Te3 tie line, the amorphous network can be seen as a mixture of the two binary compounds GaTe and GaSb with intertwined elemental Sb.

Development in Zn4Sb-based thermoelectric materials

DEFF Research Database (Denmark)

Yin, Hao

or thermopower,  the electrical conductivity, the thermal conductivity and T the absolute temperature. The best thermoelectrics are heavily doped semiconductors with high thermoelectric power factors and low thermal conductivities, known as “Phonon Glasses Electrical Crystals”. Zn4Sb3 is one such material......-section. The following part reports the effect of nano-particles on the thermoelectric properties and thermal stability of Zn4Sb3. Though TiO2 nano particles have remarkably enhanced the stability, the thermoelectric performance of all the nano-composites deteriorates. Optimization of the content of the nano...

Multilayer SnSb4-SbSe Thin Films for Phase Change Materials Possessing Ultrafast Phase Change Speed and Enhanced Stability.

Science.gov (United States)

Liu, Ruirui; Zhou, Xiao; Zhai, Jiwei; Song, Jun; Wu, Pengzhi; Lai, Tianshu; Song, Sannian; Song, Zhitang

2017-08-16

A multilayer thin film, comprising two different phase change material (PCM) components alternatively deposited, provides an effective means to tune and leverage good properties of its components, promising a new route toward high-performance PCMs. The present study systematically investigated the SnSb 4 -SbSe multilayer thin film as a potential PCM, combining experiments and first-principles calculations, and demonstrated that these multilayer thin films exhibit good electrical resistivity, robust thermal stability, and superior phase change speed. In particular, the potential operating temperature for 10 years is shown to be 122.0 °C and the phase change speed reaches 5 ns in the device test. The good thermal stability of the multilayer thin film is shown to come from the formation of the Sb 2 Se 3 phase, whereas the fast phase change speed can be attributed to the formation of vacancies and a SbSe metastable phase. It is also demonstrated that the SbSe metastable phase contributes to further enhancing the electrical resistivity of the crystalline state and the thermal stability of the amorphous state, being vital to determining the properties of the multilayer SnSb 4 -SbSe thin film.

Treatment for GaSb surfaces using a sulphur blended (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4} solution

Energy Technology Data Exchange (ETDEWEB)

Murape, D.M., E-mail: Davison.Murape@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Eassa, N.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa)

2012-07-01

A sulphur based chemical, [(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na{sub 2}S{center_dot}9H{sub 2}O and (NH{sub 4}){sub 2}S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) than with (NH{sub 4}){sub 2}S or Na{sub 2}S{center_dot}9H{sub 2}O, as evidenced by the ratio of the O{sub 506eV} to Sb{sub 457eV} AES peaks. XPS results reveal that Sb{sub 2}S{sub 3}/Sb{sub 2}S{sub 5} 'replaces' Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5}, suggesting that sulphur atoms substitute oxygen atoms in Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5} to form Sb-S. It seems sulphurization only partially removes Ga{sub 2}O{sub 3}. Treatment with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

Study of magnetic structure of neptunium compounds: Np As, Np Sb, Np Se et Np Ru2 Si2

International Nuclear Information System (INIS)

Bonnisseau, D.

1987-11-01

Magnetic behavior and localization of 5f electrons in actinide compounds is studied experimentally by Moessbauer spectroscopy and neutron diffraction. Binary actinide compounds with a NaCl structure are examined and properties of U, Pu and Np monopnictides and monochalcogenides are recalled. Results of neutron diffraction by NpAs and NpSb are discussed and results of magnetic susceptibility, magnetization, Moessbauer spectroscopy and neutron diffraction measurements on NpSe and NpTe are presented. Magnetic properties of NpRu 2 Si 2 are also presented. Heavy fermion system electronic and magnetic properties are described and theory is discussed. Electronic and magnetic properties of CeCu 2 Si 2 , CeRu 2 Si 2 and URu 2 Si 2 are compared to NpRu 2 Si 2 which has the same crystal structure [fr

The Enzyme Activity and Substrate Specificity of Two Major Cinnamyl Alcohol Dehydrogenases in Sorghum (Sorghum bicolor), SbCAD2 and SbCAD4.

Science.gov (United States)

Jun, Se-Young; Walker, Alexander M; Kim, Hoon; Ralph, John; Vermerris, Wilfred; Sattler, Scott E; Kang, ChulHee

2017-08-01

Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in monolignol biosynthesis, reducing sinapaldehyde, coniferaldehyde, and p -coumaraldehyde to their corresponding alcohols in an NADPH-dependent manner. Because of its terminal location in monolignol biosynthesis, the variation in substrate specificity and activity of CAD can result in significant changes in overall composition and amount of lignin. Our in-depth characterization of two major CAD isoforms, SbCAD2 (Brown midrib 6 [bmr6]) and SbCAD4, in lignifying tissues of sorghum ( Sorghum bicolor ), a strategic plant for generating renewable chemicals and fuels, indicates their similarity in both structure and activity to Arabidopsis ( Arabidopsis thaliana ) CAD5 and Populus tremuloides sinapyl alcohol dehydrogenase, respectively. This first crystal structure of a monocot CAD combined with enzyme kinetic data and a catalytic model supported by site-directed mutagenesis allows full comparison with dicot CADs and elucidates the potential signature sequence for their substrate specificity and activity. The L119W/G301F-SbCAD4 double mutant displayed its substrate preference in the order coniferaldehyde > p -coumaraldehyde > sinapaldehyde, with higher catalytic efficiency than that of both wild-type SbCAD4 and SbCAD2. As SbCAD4 is the only major CAD isoform in bmr6 mutants, replacing SbCAD4 with L119W/G301F-SbCAD4 in bmr6 plants could produce a phenotype that is more amenable to biomass processing. © 2017 American Society of Plant Biologists. All Rights Reserved.

Synthesis and vibrational spectrum of antimony phosphate, SbPO4.

Science.gov (United States)

Brockner, Wolfgang; Hoyer, Lars P

2002-07-01

SbPO4 was synthesized via a new route by reacting antimony metal with meta-phosphoric acid, (HPO3)n at high temperatures. The Raman and IR spectra of the title compound were recorded and the vibrational modes assigned on the basis of a factor group analysis. The internal vibrations are derived from tetrahedral PO4 units (approaching Sb[PO4]) by the correlation method, although the structure is polymeric and not ionic.

First-principles calculations of the elastic, electronic, and optical properties of the filled skutterudites CeFe4P12 and ThFe4P12

Czech Academy of Sciences Publication Activity Database

Khenata, R.; Bouhemadou, A.; Reshak, Ali H; Ahmed, R.; Rached, D.; Al-Douri, Y.

2007-01-01

Roč. 60, č. 4 (2007), s. 463-468 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z60870520 Keywords : MAGNETIC-PROPERTIES Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.172, year: 2007

Effects upon metabolic pathways and energy production by Sb(III and As(III/Sb(III-oxidase gene aioA in Agrobacterium tumefaciens GW4.

Directory of Open Access Journals (Sweden)

Jingxin Li

Full Text Available Agrobacterium tumefaciens GW4 is a heterotrophic arsenite [As(III]/antimonite [Sb(III]-oxidizing strain. The As(III oxidase AioAB is responsible for As(III oxidation in the periplasm and it is also involved in Sb(III oxidation in Agrobacterium tumefaciens 5A. In addition, Sb(III oxidase AnoA and cellular H2O2 are also responsible for Sb(III oxidation in strain GW4. However, the deletion of aioA increased the Sb(III oxidation efficiency in strain GW4. In the present study, we found that the cell mobility to Sb(III, ATP and NADH contents and heat release were also increased by Sb(III and more significantly in the aioA mutant. Proteomics and transcriptional analyses showed that proteins/genes involved in Sb(III oxidation and resistance, stress responses, carbon metabolism, cell mobility, phosphonate and phosphinate metabolism, and amino acid and nucleotide metabolism were induced by Sb(III and were more significantly induced in the aioA mutant. The results suggested that Sb(III oxidation may produce energy. In addition, without periplasmic AioAB, more Sb(III would enter bacterial cells, however, the cytoplasmic AnoA and the oxidative stress response proteins were significantly up-regulated, which may contribute to the increased Sb(III oxidation efficiency. Moreover, the carbon metabolism was also activated to generate more energy against Sb(III stress. The generated energy may be used in Sb transportation, DNA repair, amino acid synthesis, and cell mobility, and may be released in the form of heat.

High quality InAsSb grown on InP substrates using AlSb/AlAsSb buffer layers

International Nuclear Information System (INIS)

Wu, B.-R.; Liao, C.; Cheng, K. Y.

2008-01-01

High quality InAsSb grown on semi-insulating InP substrates by molecular beam epitaxy was achieved using AlSb/AlAsSb structure as the buffer layer. A 1000 A InAsSb layer grown on top of 1 μm AlSb/AlAsSb buffer layer showed a room temperature electron mobility of ∼12 000 cm 2 /V s. High structural quality and low misfit defect density were also demonstrated in the InAsSb layer. This novel AlSb/AlAsSb buffer layer structure with the AlAsSb layer lattice matched to InP substrates could enhance the performance of optoelectronic devices utilizing 6.1 A family of compound semiconductor alloys

Crystal structure, chemical bond and enhanced performance of β-Zn{sub 4}Sb{sub 3} compounds with interstitial indium dopant

Energy Technology Data Exchange (ETDEWEB)

Tang, Dingguo [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Key Laboratory of Catalysis and Materials Science of the State Ethnic Affair Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074 (China); Zhao, Wenyu, E-mail: wyzhao@whut.edu.cn [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Yu, Jian; Wei, Ping; Zhou, Hongyu; Zhu, Wanting [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Qingjie, E-mail: zhangqj@whut.edu.cn [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2014-07-15

Highlights: • The interstitial In dopant leads to the local structural perturbations in β-Zn{sub 4}Sb{sub 3}. • The simultaneous increases in α and σ are observed in the In-doped Zn{sub 4}Sb{sub 3} compounds. • The In dopant plays different doping behaviors by the dopant contents in the samples. • A maximum ZT of 1.41 at 700 K is achieved for the In-doped Zn{sub 4}Sb{sub 3} compounds. - Abstract: In-doped β-Zn{sub 4}Sb{sub 3} compounds (Zn{sub 4−x}In{sub x}Sb{sub 3}, 0 ⩽ x ⩽ 0.24) were prepared by melt-quenching and spark plasma sintering technology in the work. The resultant samples were systematically investigated by X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry and thermoelectric property measurements. The In dopant was identified to preferentially occupy the interstitial site in β-Zn{sub 4}Sb{sub 3} and led to the local structural perturbations near the 12c Sb2 and 36f Zn1 sites. The Auger parameters of Zn and Sb indicated that the increase in the valence of Zn was attributed to the charge transfer from Zn to In atoms. The binding energies of In 3d{sub 5/2} core level showed that the interstitial In dopant was n-type dopant (In{sup 3+}) in slightly In-doped Zn{sub 4−x}In{sub x}Sb{sub 3}, but acted as acceptor and was p-type dopant (In{sup +}) in heavily In-doped ones. The discovery provides a reasonable explanation for the puzzled relation between σ and x for Zn{sub 4−x}In{sub x}Sb{sub 3}. Simultaneously increasing the electrical conductivity and Seebeck coefficient of Zn{sub 4−x}In{sub x}Sb{sub 3} can be realized through the local structural perturbations. The significantly enhanced power factor and the intrinsic low thermal conductivity resulted in a remarkable increase in the dimensionless figure of merit (ZT). The highest ZT reached 1.41 at 700 K for Zn{sub 3.82}In{sub 0.18}Sb{sub 3} and increased by 68% compared with that of the undoped β-Zn{sub 4}Sb{sub 3}.

Radioiodinated SB 207710 as a radioligand in vivo: imaging of brain 5-HT{sub 4} receptors with SPET

Energy Technology Data Exchange (ETDEWEB)

Pike, Victor W. [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, MD 20892-1003, Bethesda (United States); Halldin, Christer; Nobuhara, Kenji; Swahn, Carl-Gunnar; Karlsson, Per; Olsson, Hans; Larsson, Stig; Schnell, Per-Olof; Farde, Lars [Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Karolinska Hospital, 17176, Stockholm (Sweden); Hiltunen, Julka [MAP Medical Technologies, Oy, Tikkakoski (Finland); Mulligan, Rachel S. [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Institute of Psychiatry, SE 8AF, De Crespigny Park, Denmark Hill, London (United Kingdom); Centre for PET, Austin and Repatriation Medical Centre, Studley Road, Melbourne VIC 3084 (Australia); Hume, Susan P.; Hirani, Ella [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Imaging Research Solutions Ltd., Cyclotron Building, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Whalley, Jaqueline [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Pilowsky, Lyn S. [Institute of Psychiatry, SE 8AF, De Crespigny Park, Denmark Hill, London (United Kingdom); Institute of Nuclear Medicine, Royal Free and University College, Medical School, Mortimer Street, W1N 8AA, London (United Kingdom); Ell, Peter J. [Institute of Nuclear Medicine, Royal Free and University College, Medical School, Mortimer Street, W1N 8AA, London (United Kingdom)

2003-11-01

Single-photon emission tomography (SPET) and positron emission tomography (PET), when coupled to suitable radioligands, are uniquely powerful for investigating the status of neurotransmitter receptors in vivo. The serotonin subtype-4 (5-HT{sub 4}) receptor has discrete and very similar distributions in rodent and primate brain. This receptor population may play a role in normal cognition and memory and is perhaps perturbed in some neuropsychiatric disorders. SB 207710 [(1-butyl-4-piperidinylmethyl)-8-amino-7-iodo-1,4-benzodioxan-5-carboxylate] is a selective high-affinity antagonist at 5-HT{sub 4} receptors. We explored radioiodinated SB 207710 as a possible radioligand for imaging 5-HT{sub 4} receptors in vivo. Rats were injected intravenously with iodine-125 labelled SB 207710, euthanised at known times and dissected to establish radioactivity content in brain tissues. Radioactivity entered brain but cleared rapidly and to a high extent from blood and plasma. Between 45 and 75 min after injection, the ratios of radioactivity concentration in each of 12 selected brain tissues to that in receptor-poor cerebellum correlated with previous measures of 5-HT{sub 4} receptor density distribution in vitro. The highest ratio was about 3.4 in striatum. SB 207710 was labelled with iodine-123 by an iododestannylation procedure. A cynomolgus monkey was injected intravenously with [{sup 123}I]SB 207710 and examined by SPET. Maximal whole brain uptake of radioactivity was 2.3% of the injected dose at 18 min after radioligand injection. Brain images acquired between 9 and 90 min showed high radioactivity uptake in 5-HT{sub 4} receptor-rich regions, such as striatum, and low uptake in receptor-poor cerebellum. At 169 min the ratio of radioactivity concentration in striatum to that in cerebellum was 4.0. In a second SPET experiment, the cynomolgus monkey was pretreated with a selective 5-HT{sub 4} receptor antagonist, SB 204070, at 20 min before [{sup 123}I]SB 207710 injection

Superlattice-like SnSb{sub 4}/Ga{sub 3}Sb{sub 7} thin films for ultrafast switching phase-change memory application

Energy Technology Data Exchange (ETDEWEB)

Hu, Yifeng [Tongji University, Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Functional Materials Research Laboratory, School of Materials Science and Engineering, Shanghai (China); Jiangsu University of Technology, School of Mathematics and Physics, Changzhou (China); He, Zifang; Zhai, Jiwei [Tongji University, Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Functional Materials Research Laboratory, School of Materials Science and Engineering, Shanghai (China); Wu, Pengzhi; Lai, Tianshu [Sun Yat-Sen University, State Key Laboratory of Optoelectronic Materials and Technology, Department of Physics, Guangzhou (China); Song, Sannian; Song, Zhitang [Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Shanghai (China)

2015-11-15

The carrier concentration of Sb-rich phase SnSb{sub 4}, Ga{sub 3}Sb{sub 7} and superlattice-like [SnSb{sub 4}(3.5 nm)/Ga{sub 3}Sb{sub 7}(4 nm)]{sub 7} (SLL-7) thin films as a function of annealing temperature was investigated to explain the reason of resistance change. The activation energy for crystallization was calculated with a Kissinger equation to estimate the thermal stability. In order to illuminate the transition mechanisms, the crystallization kinetics of SLL-7 were explored by using Johnson-Mehl-Avrami theory. The obtained values of Avrami indexes indicate that a one-dimensional growth-dominated mechanism is responsible for the set transition of SLL-7 thin film. X-ray diffractometer and Raman scattering spectra were recorded to investigate the change of crystalline structure. The measurement of atomic force microscopy indicated that SLL-7 thin film has a good smooth surface. A picosecond laser pump-probe system was used to test and verify phase-change speed of the SLL-7 thin film. (orig.)

Syntheses, and crystal and electronic structures of the new Zintl phases Na2ACdSb2 and K2ACdSb2 (A=Ca, Sr, Ba, Eu, Yb): Structural relationship with Yb2CdSb2 and the solid solutions Sr2-xAxCdSb2, Ba2-xAxCdSb2 and Eu2-xYbxCdSb2

International Nuclear Information System (INIS)

Saparov, Bayrammurad; Saito, Maia; Bobev, Svilen

2011-01-01

Presented are the details of the syntheses, crystal and electronic structures of a new family of Zintl phases Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb), as well as the solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 and Eu 2-x Yb x CdSb 2 . The structures of Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) were determined to be of a new type with the non-centrosymmetric space group Pmc2 1 (no. 26), Pearson symbol oP12, with lattice parameters a=4.684(1)-4.788(1) A; b=9.099(3)-9.117(2) A; c=7.837(1)-8.057(2) A for the Na 2 ACdSb 2 series, and a=4.6637(9)-5.0368(8) A; b=9.100(2)-9.8183(15) A; and c=7.7954(15)-8.4924(13) A for K 2 ACdSb 2 , respectively. The solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 and Eu 2-x Yb x CdSb 2 (x∼1) are isostructural and isoelectronic to the recently reported Yb 2 CdSb 2 (space group Cmc2 1 (no. 36), Pearson symbol cP20). All discussed structures are based upon CdSb 2 4- polyanionic layers, similar to the ones observed in Yb 2 CdSb 2 , with various alkali- and/or alkaline-earth cations coordinated to them. Magnetic susceptibility and Seebeck coefficient measurements on selected Eu 2-x Yb x CdSb 2 samples, taken at low temperatures up to 300 K, are also reported. -- Graphical abstract: The quaternary Zintl phases Na 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) with novel layered structures have been synthesized for the first time and structurally characterized by single-crystal X-ray diffraction. Reported as well are the results from crystallographic and property studies of the closely related solid solutions Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 (x∼1), and Eu 2-x Yb x CdSb 2 (1 2 ACdSb 2 and K 2 ACdSb 2 (A=Ca, Sr, Ba, Eu, Yb) are new quaternary Zintl phases. → Sr 2-x A x CdSb 2 , Ba 2-x A x CdSb 2 (x∼1), and Eu 2-x Yb x CdSb 2 (1 4 tetrahedra. → Eu 2-x Yb x CdSb 2 (1< x<2) exhibit high Seebeck coefficient (217 μV/K at RT).

Study of interatomic potential and thermal structural properties of β-Zn4Sb3

International Nuclear Information System (INIS)

Li, Guodong; Li, Yao; Liu, Lisheng; Zhang, Qingjie; Zhai, Pengcheng

2012-01-01

Highlights: ► The multi-body interatomic potentials of various models of β-Zn 4 Sb 3 have been developed to describe atomic interactions. ► The radial distribution function shows that the 10% vacancy of Zn site leads to the disorder of β-Zn 4 Sb 3 . ► The 10% vacancy of Zn site is the main cause of the exceptional low thermal conductivity. -- Abstract: Previous experimental research shows that the disordered Zn atoms in β-Zn 4 Sb 3 may have an important influence on its exceptionally low thermal conductivity and easily occurred phase transition. So the present work aims to study the influence of disordered Zn atoms on thermodynamics properties of β-Zn 4 Sb 3 by using molecular dynamics (MD) method. Firstly, based on first principles calculation and experimental results, the interatomic potentials of β-Zn 4 Sb 3 and MD analysis method are established, and the feasibility is verified. Then, the influence of disordered Zn atoms on thermal conductivity of β-Zn 4 Sb 3 is studied in detail. The simulation results indicate that the 10% vacant Zn atoms is the main reason for the exceptionally low thermal conductivity of β-Zn 4 Sb 3 , and it seems that the interstitial Zn atoms have little effect on its thermal conductivity.

Solid Liquid Interdiffusion Bonding of Zn4Sb3 Thermoelectric Material with Cu Electrode

Science.gov (United States)

Lin, Y. C.; Lee, K. T.; Hwang, J. D.; Chu, H. S.; Hsu, C. C.; Chen, S. C.; Chuang, T. H.

2016-10-01

The ZnSb intermetallic compound may have thermoelectric applications because it is low in cost and environmentally friendly. In this study, a Zn4Sb3 thermoelectric element coated with a Ni barrier layer and a Ag reaction layer was bonded with a Ag-coated Cu electrode using a Ag/Sn/Ag solid-liquid interdiffusion bonding process. The results indicated that a Ni5Zn21 intermetallic phase formed easily at the Zn4Sb3/Ni interface, leading to sound adhesion. In addition, Sn film was found to react completely with the Ag layer to form a Ag3Sn intermetallic layer having a melting point of 480°C. The resulting Zn4Sb3 thermoelectric module can be applied at the optimized operation temperature (400°C) of Zn4Sb3 material as a thermoelectric element. The bonding strengths ranged from 14.9 MPa to 25.0 MPa, and shear tests revealed that the Zn4Sb3/Cu-joints fractured through the interior of the thermoelectric elements.

Ordered perovskites with cationic vacancies. 7. Structural investigations on Ba/sub 2/Zrsub(3/4)vacantsub(1/4)SbO/sub 6/

Energy Technology Data Exchange (ETDEWEB)

Treiber, U; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1980-11-01

The ochre coloured Ba/sub 2/Zrsub(3/4)vacantsub(1/4)SbO/sub 6/ belongs to the group of oxygen perovskites with an ordered distribution of the vacancies. It crystallizes tetragonal (a = 11.68/sub 5/ A; c = 16.60/sub 6/ A) with 16 formula units in the cell: Ba/sub 32/Zr/sub 12/vacant/sub 4/Sb/sub 16/O/sub 96/. For the space group P 4/mmm intensity calculations on powder data gave a refined, intensity related R' value of 4.8%. In the structure the Zr and Ba atoms are ordered (1:1 order); the four cationic vacancies are located in a face centered arrangement in the zirconium sublattice. The Ba atoms are displaced by approximately 0.20 A in direction of the neighbouring vacancy, while the other cations maintain their ideal positions.

Tav4SB: integrating tools for analysis of kinetic models of biological systems.

Science.gov (United States)

Rybiński, Mikołaj; Lula, Michał; Banasik, Paweł; Lasota, Sławomir; Gambin, Anna

2012-04-05

Progress in the modeling of biological systems strongly relies on the availability of specialized computer-aided tools. To that end, the Taverna Workbench eases integration of software tools for life science research and provides a common workflow-based framework for computational experiments in Biology. The Taverna services for Systems Biology (Tav4SB) project provides a set of new Web service operations, which extend the functionality of the Taverna Workbench in a domain of systems biology. Tav4SB operations allow you to perform numerical simulations or model checking of, respectively, deterministic or stochastic semantics of biological models. On top of this functionality, Tav4SB enables the construction of high-level experiments. As an illustration of possibilities offered by our project we apply the multi-parameter sensitivity analysis. To visualize the results of model analysis a flexible plotting operation is provided as well. Tav4SB operations are executed in a simple grid environment, integrating heterogeneous software such as Mathematica, PRISM and SBML ODE Solver. The user guide, contact information, full documentation of available Web service operations, workflows and other additional resources can be found at the Tav4SB project's Web page: http://bioputer.mimuw.edu.pl/tav4sb/. The Tav4SB Web service provides a set of integrated tools in the domain for which Web-based applications are still not as widely available as for other areas of computational biology. Moreover, we extend the dedicated hardware base for computationally expensive task of simulating cellular models. Finally, we promote the standardization of models and experiments as well as accessibility and usability of remote services.

Preparation and crystal structure of Ca/sub 4/Sb/sub 2/O

Energy Technology Data Exchange (ETDEWEB)

Eisenmann, B; Limartha, H; Schaefer, H; Graf, H A

1980-12-01

The formerly described compound Ca/sub 2/Sb is to be corrected to Ca/sub 4/Sb/sub 2/O as shown by X-ray diffractometer data of single crystals and neutron diffraction diagrams of powders. The compound crystallizes in the K/sub 2/NiF/sub 4/ type structure.

Novel quantum criticality in CeRu2Si2 near absolute zero observed by thermal expansion and magnetostriction.

Science.gov (United States)

Yoshida, J; Abe, S; Takahashi, D; Segawa, Y; Komai, Y; Tsujii, H; Matsumoto, K; Suzuki, H; Onuki, Y

2008-12-19

We report linear thermal expansion and magnetostriction measurements for CeRu2Si2 in magnetic fields up to 52.6 mT and at temperatures down to 1 mK. At high temperatures, this compound showed Landau-Fermi-liquid behavior: The linear thermal expansion coefficient and the magnetostriction coefficient were proportional to the temperature and magnetic field, respectively. In contrast, a pronounced non-Fermi-liquid effect was found below 50 mK. The negative contribution of thermal expansion and magnetostriction suggests the existence of an additional quantum critical point.

Properties of CoSb{sub 3} films grown by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Christen, H M; Mandrus, D G; Norton, D P; Boatner, L A; Sales, B C

1997-07-01

Polycrystalline CoSb{sub 3} films were grown on a variety of electrically insulating substrates by pulsed laser ablation from a stoichiometric hot-pressed target. These films are fully crystallized in the skutterudite structure, and the grains exhibit a strongly preferred alignment of the cubic [310]-axis perpendicular to the substrate surface. The film quality is studied for different single-crystal substrates and as a function of growth temperature and background gas. Hall measurements show that the films are p-type semiconducting with a room-temperature carrier density of 3 x 10{sup 20} holes/cm{sup 3}. The Hall mobility is found to be 50 to 60 cm{sup 2}/Vs, which is high for such a heavily-doped material. The Seebeck coefficient and the resistivity are measured as a function of temperature and are compared to bulk measurements.

Unraveling the electrolyte properties of Na3SbS4 through computation and experiment

Science.gov (United States)

Rush, Larry E.; Hood, Zachary D.; Holzwarth, N. A. W.

2017-12-01

Solid-state sodium electrolytes are expected to improve next-generation batteries on the basis of favorable energy density and reduced cost. Na3SbS4 represents a new solid-state ion conductor with high ionic conductivities in the mS/cm range. Here, we explore the tetragonal phase of Na3SbS4 and its interface with metallic sodium anode using a combination of experiments and first-principles calculations. The computed Na-ion vacancy migration energies of 0.1 eV are smaller than the value inferred from experiment, suggesting that grain boundaries or other factors dominate the experimental systems. Analysis of symmetric cells of the electrolyte—Na/Na 3SbS4/Na —show that a conductive solid electrolyte interphase forms. Computer simulations infer that the interface is likely to be related to Na3SbS3 , involving the conversion of the tetrahedral SbS43 - ions of the bulk electrolyte into trigonal pyramidal SbS33 - ions at the interface.

Disordered Zinc in Zn4Sb3 with Phonon-Glass and Electron-Crystal Thermoelectric Properties

Science.gov (United States)

Snyder, G. Jeffrey; Christensen, Mogens; Nishibori, Eiji; Caillat, Thierry; Brummerstedt Iversen, Bo

2004-01-01

By converting waste heat into electricity, thermoelectric generators could be an important part of the solution to today's energy challenges. The compound Zn4Sb3 is one of the most efficient thermoelectric materials known. Its high efficiency results from an extraordinarily low thermal conductivity in conjunction with the electronic structure of a heavily doped semiconductor. Previous structural studies have been unable to explain this unusual combination of properties. Here, we show through a comprehensive structural analysis using single-crystal X-ray and powder-synchrotron-radiation diffraction methods, that both the electronic and thermal properties of Zn4Sb3 can be understood in terms of unique structural features that have been previously overlooked. The identification of Sb3- ions and Sb-2(4-) dimers reveals that Zn4Sb3 is a valence semiconductor with the ideal stoichiometry Zn13Sb10. In addition, the structure contains significant disorder, with zinc atoms distributed over multiple positions. The discovery of glass-like interstitial sites uncovers a highly effective mechanism for reducing thermal conductivity. Thus Zn4Sb3 is in many ways an ideal 'phonon glass, electron crystal' thermoelectric material.

Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

KAUST Repository

Sarath Kumar, S. R.; Cha, Dong Kyu; Alshareef, Husam N.

2011-01-01

Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single

Ba{sub 4}In{sub 8}Sb{sub 16}: Thermoelectric properties of a new layered Zintl phase with infinite zigzag Sb chains and pentagonal tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, S J; Hu, S; Uher, C; Kanatzidis, M G

1999-11-01

A new Zintl phase Ba{sub 4}In{sub 8}Sb{sub 16} was obtained from a direct element combination reaction of the elements in a sealed graphite tube at 700 C, and its structure was determined by single-crystal X-ray diffraction methods. It crystallizes in the orthorhombic space group Pnma (No. 62) with a = 10.166(3) {angstrom}, b = 4.5239(14) {angstrom}, c = 19.495(6) {angstrom}, and Z = 1. Ba{sub 4}In{sub 8}Sb{sub 16} has a two-dimensional structure with thick corrugated (In{sub 8}Sb{sub 16}){sup 8{minus}} layers separated by Ba{sup 2+} ions. In the layer, InSb{sub 4} tetrahedra are connected by sharing three corners and by bridging the fourth corner in such a manner that infinite pentagonal tubes are formed. The compound is a narrow band gap ({approximately} 0.10 eV) semiconductor and satisfies the classical Zintl rule. Band structure calculations confirm that the material is a semiconductor and indicate that it has optimized In-Sb bonding interactions. Polycrystalline ingots of Ba{sub 4}In{sub 8}Sb{sub 16} show room-temperature electrical conductivity of 135 S/cm and a Seebeck coefficient of 70 {micro}V/K. The thermal conductivity of Ba{sub 4}In{sub 8}Sb{sub 16} is about 1.7 W/m{sm{underscore}bullet}K in the temperature range 150--300 K.

Chemical and electrical properties of (NH4)2S passivated GaSb surface

International Nuclear Information System (INIS)

Tao Dongyan; Cheng Yu; Liu Jingming; Su Jie; Liu Tong; Yang Fengyun; Wang Fenghua; Cao Kewei; Dong Zhiyuan; Zhao Youwen

2015-01-01

The surface chemical properties of gallium antimonide (GaSb) after ammonium sulfide ((NH 4 ) 2 S) solution passivation have been studied by X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectroscopy (TOF-SIMS) and I–V measurement. An advantage of neutral (NH 4 ) 2 S + S solution over pure (NH 4 ) 2 S solution and alkaline (NH 4 ) 2 S + S solution has been found in the ability to passivate the GaSb surface by contrast and comparison. It has been found that alkaline (NH 4 ) 2 S + S solution passivation effectively removes oxides of the GaSb surface and forms sulfide products to improve device performance. TOF-SIMS complementally demonstrates that pure (NH 4 ) 2 S passivation did form sulfide products, which are too soluble to really exist. The lowest roughness determined using a 3D optical profilometer and the highest improved SBD quality proved that neutral (NH 4 ) 2 S + S solution passivation worked much better in improving the surface properties of GaSb. (paper)

A new solid solution compound with the Sr{sub 21}Mn{sub 4}Sb{sub 18} structure type. Sr{sub 13}Eu{sub 8}Cd{sub 3}Mn{sub 1}Sb{sub 18}

Energy Technology Data Exchange (ETDEWEB)

Kunz Wille, Elizabeth L.; Cooley, Joya A.; Fettinger, James C.; Kazem, Nasrin; Kauzlarich, Susan M. [California Univ., Davis, CA (United States). Dept. of Chemistry

2017-09-01

The title compound with the nominal formula, Sr{sub 13}Eu{sub 8}Cd{sub 3}Mn{sub 1}Sb{sub 18}, was synthesized by Sn-flux. Structure refinement was based on single-crystal X-ray diffractometer data. Employing the exact composition, the formula is Sr{sub 13.23}Eu{sub 7.77}Cd{sub 3.12}Mn{sub 0.88}Sb{sub 18} for the solid solution Sr{sub 21-x}Eu{sub x}Cd{sub 4-y}Mn{sub y}Sb{sub 18}. This phase adopts the Sr{sub 21}Mn{sub 4}Sb{sub 18} type structure with site preferences for both Eu and Cd. The structure crystallizes in the monoclinic system in space group C2/m and Z=4: a=18.1522(11), b=17.3096(10), c=17.7691(10) Aa, β=91.9638(8) , 6632 F{sup 2} values, 216 variables, R1=0.0254 and wR2=0.0563. Site selectivity of the elements in this new compound will be discussed in relationship with the Sr{sub 21}Mn{sub 4}Sb{sub 18} type structure and other related structure types. Temperature dependent magnetic susceptibility data reveal Curie-Weiss paramagnetism with an experimental moment of 19.3 μ{sub B}/f.u. and a Weiss constant of 0.4 K. Magnetic ordering is seen at low temperatures, with a transition temperature of 3.5 K.

Chemical consequences of the neutron irradiation of ionic antimony oxides and Fe Sb2O4

Energy Technology Data Exchange (ETDEWEB)

Facetti, J F [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

1970-01-01

The chemical consequences fo the neutron irradiation of ionic antimony oxides and Fe Sb2O4 are studied. The nature of the Sb-O2 bond effects the yield of SbV the higher the yield the more covalent the bond. In addition, the Fe Sb2O4 obeys the Maddock's rule.

Molecular dynamics simulation on mechanical properties of crystalline CoSb3 with vacancy defect

International Nuclear Information System (INIS)

Yang Xuqiu; Zhai Pengcheng; Liu Lisheng; Zhang Qingjie

2012-01-01

The present work has investigated the tensile mechanical behavior of the skutterudite CoSb 3 single-crystal in the presence of antimony vacancies, since the antimony atoms in CoSb 3 are active and are usually easy to lose in practice. The molecular dynamics simulation method is employed. The vacancy atoms, whose fraction is limited up to 5%, are chosen randomly. The virtual uniaxial tension is carried out by strain controlling along a principal crystallographic direction at 300 K. The specimens with vacancies show similar stress-strain response features to there of the perfect crystal. However, the effective Young's modulus decreases linearly with the increase of the vacancy content, and the ultimate strength drops substantially from no vacancy to even a small vacancy fraction. Temperature dependence of the simulation results is also considered. Both Young's modulus and the ultimate strength exhibit an approximately linear reduction with increasing temperature for a specific vacancy fraction, and moreover, the reduction rate is comparable for different vacancy fractions. The Vacancy distribution effect is briefly discussed as well. As the vacancy concentration becomes uniform, the ultimate strength of the material would be promoted significantly.

The Influence of Growth Temperature on Sb Incorporation in InAsSb, and the Temperature-dependent Impact of Bi Surfactants

Science.gov (United States)

2014-01-01

temperature was set to give a beam equivalent pressure ( BEP ) of 4.8x10-7 Torr, as measured in this configuration. 10 4 We have shown in prior...to the value needed to grow lattice matched InAsSb on GaSb without using Bi surfactant at 415 C. The In growth rate was 1 m/hr. The Sb BEP was...1.2x10-7 Torr and the As BEP was 5.71x10-7 Torr. The absolute flux of all the constituents and the V/III ratios were kept constant for both layers of

Ternary CaCu4P2-type pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb)

Science.gov (United States)

Stoyko, Stanislav S.; Khatun, Mansura; Scott Mullen, C.; Mar, Arthur

2012-08-01

Four ternary pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb) were prepared by reactions of the elements at 850 °C and their crystal structures were determined from single-crystal X-ray diffraction studies. These silver-containing pnictides AAg4Pn2 adopt the trigonal CaCu4P2-type structure (Pearson symbol hR21, space group R3¯m, Z=3; a=4.5555(6) Å, c=24.041(3) Å for SrAg4As2; a=4.5352(2) Å, c=23.7221(11) Å for EuAg4As2; a=4.7404(4) Å, c=25.029(2) Å for SrAg4Sb2; a=4.7239(3) Å, c=24.689(2) Å for EuAg4Sb2), which can be derived from the trigonal CaAl2Si2-type structure of the isoelectronic zinc-containing pnictides AZn2Pn2 by insertion of additional Ag atoms into trigonal planar sites within [M2Pn2]2- slabs built up of edge-sharing tetrahedra. Band structure calculations on SrAg4As2 and SrAg4Sb2 revealed that these charge-balanced Zintl phases actually exhibit no gap at the Fermi level and are predicted to be semimetals.

Ex vivo evaluation of coronal and apical microbial leakage of root canal - Filled with gutta-percha or Resilon/Epiphany root canal filling material

Directory of Open Access Journals (Sweden)

de Almeida-Gomes Fabio

2010-01-01

Full Text Available Objective: This ex vivo study compared coronal and apical microleakage of root canals filled with Resilon/Epiphany (RE or gutta-percha/Grossman sealer (GP, using either lateral condensation (LC or System B (SB technique. Materials and Methods: Specimens in eight experimental groups were obturated using the following materials and techniques: Groups 1 and 3 - GP and LC; groups 2 and 4 - GP and SB; groups 5 and 7 - RE and LC; groups 6 and 8 - RE and SB. Apical and coronal leakages were tested using bacterial methods. For coronal analysis, the number of days required for complete contamination of the root canals was recorded according to observation of the brain heart infusion broth turbidity for 15 weeks. For apical analysis, the teeth were cleaved and the leakage was measured at 30 days. Data were collected for each sample and analyzed statistically with the Chi-square and ANOVA tests. Results: Leakage was found in all groups. The difference between filling materials, obturation techniques, and median time of leakage was not statistically significant for coronal ( P=0.847 and apical ( P=0.5789 leakages. Conclusion: There were no differences between the different filling materials (gutta-percha/Grossman sealer and Resilon/Epiphany and obturation techniques (lateral condensation and system B technique in coronal or apical leakages.

Improved GaSb surfaces using a (NH4)2S/(NH4)2S04 solution

International Nuclear Information System (INIS)

Murape, D.M.; Eassa, N.; Nyamhere, C.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

2012-01-01

Bulk (1 0 0) n-GaSb surfaces have been treated with a sulphur based solution ((NH 4 ) 2 S/(NH 4 ) 2 SO 4 ) to which sulphur has been added, not previously reported for the passivation of GaSb surfaces. Au/n-GaSb Schottky barrier diodes (SBDs) fabricated on the treated material show significant improvement compared to that of the similar SBDs on the as-received material as evidenced by the lower ideality factor (n), higher barrier height (φ b ) and lower contact resistance obtained. Additionally, the reverse leakage current, although not saturating, has been reduced by almost an order of magnitude at −0.2 V. The sample surfaces were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The native oxide, Sb–O, present on the as-received material is effectively removed on treating with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ]+S) and (NH 4 ) 2 S. Analysis of the as-received surface by XPS, prior to and after argon sputtering, suggests that the native oxide layer is ≤8.5 nm.

Topotactic Fluorine Insertion into the Channels of FeSb2O4-Related Materials.

Science.gov (United States)

de Laune, Benjamin P; Rees, Gregory J; Marco, José F; Hah, Hien-Yoong; Johnson, Charles E; Johnson, Jacqueline A; Berry, Frank J; Hanna, John V; Greaves, Colin

2017-08-21

This paper discusses the fluorination characteristics of phases related to FeSb 2 O 4 , by reporting the results of a detailed study of Mg 0.50 Fe 0.50 Sb 2 O 4 and Co 0.50 Fe 0.50 Sb 2 O 4 . Reaction with fluorine gas at low temperatures (typically 230 °C) results in topotactic insertion of fluorine into the channels, which are an inherent feature of the structure. Neutron powder diffraction and solid state NMR studies show that the interstitial fluoride ions are bonded to antimony within the channel walls to form Sb-F-Sb bridges. To date, these reactions have been observed only when Fe 2+ ions are present within the chains of edge-linked octahedra (FeO 6 in FeSb 2 O 4 ) that form the structural channels. Oxidation of Fe 2+ to Fe 3+ is primarily responsible for balancing the increased negative charge associated with the presence of the fluoride ions within the channels. For the two phases studied, the creation of Fe 3+ ions within the chains of octahedra modify the magnetic exchange interactions to change the ground-state magnetic symmetry to C-type magnetic order in contrast to the A-type order observed for the unfluorinated oxide parents.

Theoretical investigation of the vortex state in new superconductors: MgB2 and PrOs4Sb12

International Nuclear Information System (INIS)

Dao, V.H.

2006-01-01

As illustrated by the present thesis work, gap function anisotropy and crystal anisotropy are combined when influencing superconducting properties under a magnetic field. In order to study the mixed state of the recently discovered multiband superconductor MgB 2 , we first derive the Ginzburg-Landau functional for a two-gap superconductor from a weak coupling BCS model. The interaction between the two condensates is then described by a unique Josephson-type coupling. The two-gap theory then enables to explain the curvature and the anisotropy of the upper critical field, as well as the 30 degrees change of orientation for the vortex lattice which is observed when increasing the strength of the magnetic field applied along the c-tilde axis. Besides, we investigate the vortex lattice geometry in the superconducting heavy fermion PrOs 4 Sb 12 . When taking into account non local corrections for an s-wave T h -tetrahedral superconductor, we can explain the observed deformation of the lattice by the crystal symmetry of the compound. Ab initio results of the band structures confirm quantitatively our analysis. (author)

Two-mode Diode-laser Spectroscopy with a InAsSb/InAsSbP Laser near 3.6 ćm

Czech Academy of Sciences Publication Activity Database

Civiš, Svatopluk; Danilova, A. P.; Imenkov, A. N.; Kolchanova, N. M.; Sherstnev, V. V.; Yakovlev, Yu. P.

1999-01-01

Roč. 33, č. 12 (1999), s. 1322-1327 ISSN 1063-7826 R&D Projects: GA AV ČR IAA4040708 Institutional research plan: CEZ:A54/98:Z4-040-9-ii Keywords : output frequency of InAsSb/InAsSbP * current dependence Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.565, year: 1999

Stabilization of high-temperature antimony oxide with molybdenum incorporation. Structure of Mo-doped Sb2O4 by powder neutron diffraction and extended X-ray absorption fine structure spectroscopy

International Nuclear Information System (INIS)

Teller, R.G.; Antonio, M.R.; Brazdil, J.F.; Mehicic, M.; Grasselli, R.K.

1985-01-01

It has been discovered that the presence of MoO 3 lowers the α-β transition in Sb 2 O 4 from 935 to 850 0 C with concurrent dissolution of Mo in the high-temperature (β) form. The structure of Mo-doped β-Sb 2 O 4 has been investigated by powder neutron diffraction, extended X-ray absorption fine structure (EXAFS) and Raman spectroscopies, and scanning-electron microscopy (SEM). Cell parameters: a = 12.0571 (12) A, b = 4.8335 (1) A, c = 5.3838 (6) A, β = 105.579 (5) 0 , monoclinic, space group C2/c, Z = 4. Combining the results of these techniques leads to the hypothesis that Mo is located interstitially within channels of electron density in the Sb 2 O 4 structure with concurrent vacancy of two Sb/sup III/ atoms. There is no apparent oxygen deficiency in the resulting structure. 25 references, 6 figures, 3 tables

Improved GaSb surfaces using a (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}S0{sub 4} solution

Energy Technology Data Exchange (ETDEWEB)

Murape, D.M., E-mail: Davison.Murape@live.nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Eassa, N.; Nyamhere, C.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

2012-05-15

Bulk (1 0 0) n-GaSb surfaces have been treated with a sulphur based solution ((NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}) to which sulphur has been added, not previously reported for the passivation of GaSb surfaces. Au/n-GaSb Schottky barrier diodes (SBDs) fabricated on the treated material show significant improvement compared to that of the similar SBDs on the as-received material as evidenced by the lower ideality factor (n), higher barrier height ({phi}{sub b}) and lower contact resistance obtained. Additionally, the reverse leakage current, although not saturating, has been reduced by almost an order of magnitude at -0.2 V. The sample surfaces were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The native oxide, Sb-O, present on the as-received material is effectively removed on treating with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}]+S) and (NH{sub 4}){sub 2}S. Analysis of the as-received surface by XPS, prior to and after argon sputtering, suggests that the native oxide layer is {<=}8.5 nm.

Evolution of Thermoelectric Properties of Zn4Sb3 Prepared by Mechanical Alloying and Different Consolidation Routes

Directory of Open Access Journals (Sweden)

Pee-Yew Lee

2018-05-01

Full Text Available In this research, a method combining the mechanical alloying with the vacuum sintering or hot pressing was adopted to obtain the compact of β-Zn4Sb3. Pure zinc and antimony powders were used as the starting material for mechanical alloying. These powders were mixed in the stoichiometry ratio of 4 to 3, or more Zn-rich. Single phase Zn4Sb3 was produced using a nominally 0.6 at. % Zn rich powder. Thermoelectric Zn4Sb3 bulk specimens have been fabricated by vacuum sintering or hot pressing of mechanically alloyed powders at various temperatures from 373 to 673 K. For the bulk specimens sintering at high temperature, phase transformation of β-Zn4Sb3 to ZnSb and Sb was observed due to Zn vaporization. However, single-phase Zn4Sb3 bulk specimens with 97.87% of theoretical density were successfully produced by vacuum hot pressing at 473 K. Electric resistivity, Seebeck coefficient, and thermal conductivity were evaluated for the hot pressed specimens from room temperature to 673 K. The results indicate that the Zn4Sb3 shows an intrinsic p-type behavior. The increase of Zn4Sb3 phase ratio can increase Seebeck coefficient but decrease electric conductivity. The maximum power factor and figure of merit (ZT value were 1.31 × 10−3 W/mK2 and 0.81 at 600 K, respectively. The ZT value was lower than that reported in the available data for materials prepared by conventional melt growth and hot pressed methods, but higher than the samples fabricated by vacuum melting and heat treatment techniques.

Yield of 117Sb, 118mSb, 120mSb, 122Sb, 124Sb in reactions Sn (p, xn)

International Nuclear Information System (INIS)

Dmitriev, P.P.; Konstantinov, I.O.

1993-01-01

Yield of 117 Sb, 118m Sb, 120m Sb, 122 Sb, 124 Sb from thick target depending on proton energy is measured. The maximum proton energy is 21.7±0.2 MeV. Antimony isotopes yield in separate reactions when irradiating of tin isotopes with 100% enrichment is determined using the method published earlier. The methods for production of 117 Sb, 118m Sb, 120m Sb, 122 Sb, 124 Sb with high radioisotope purity are shown. 13 refs., 1 fig., 3 tabs

Oxygen-doped Sb{sub 4}Te phase change films for high-temperature data retention and low-power application

Energy Technology Data Exchange (ETDEWEB)

Hu, Yifeng [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China); School of Mathematics and Physics, Jiangsu Teachers University of Technology, Changzhou 213001 (China); Sun, Mingcheng [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China); Song, Sannian; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Functional Materials Research Laboratory, Tongji University, Shanghai 200092 (China)

2013-02-25

Highlights: Black-Right-Pointing-Pointer O-doped Sb{sub 4}Te phase-change films were reported. Black-Right-Pointing-Pointer The amorphous-to-crystalline transitions of O-doped Sb{sub 4}Te films were studied. Black-Right-Pointing-Pointer By doping oxygen, the stability of Sb{sub 4}Te films is improved greatly. Black-Right-Pointing-Pointer The resistance of the Sb{sub 4}Te films increases by doping oxygen. - Abstract: The amorphous-to-crystalline transitions of oxygen-doped Sb{sub 4}Te (STO) films are investigated by in situ film resistance measurements. The crystalline temperature and resistance of the oxygen-doped films increase. The analysis of X-ray diffractomer (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that the films with doping of a small amount of oxygen atoms can refine the grain size and form oxide, improving the resistance and thermal stability of phase change films. Excessive oxygen in Sb{sub 4}Te will make Te separate, resulting in deteriorating the stability. As a result, STO2 film has the relatively high activation energy for crystallization. The 10-year lifetime is raised from 29 Degree-Sign C of undoped Sb{sub 4}Te film to 102 Degree-Sign C of STO3 film. Phase transition from amorphous state to crystalline state is observed at relatively lower power, compared with a device using Ge{sub 2}Sb{sub 2}Te{sub 5} film.

Ternary CaCu4P2-type pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb)

International Nuclear Information System (INIS)

Stoyko, Stanislav S.; Khatun, Mansura; Scott Mullen, C.; Mar, Arthur

2012-01-01

Four ternary pnictides AAg 4 Pn 2 (A=Sr, Eu; Pn=As, Sb) were prepared by reactions of the elements at 850 °C and their crystal structures were determined from single-crystal X-ray diffraction studies. These silver-containing pnictides AAg 4 Pn 2 adopt the trigonal CaCu 4 P 2 -type structure (Pearson symbol hR21, space group R3-bar m, Z=3; a=4.5555(6) Å, c=24.041(3) Å for SrAg 4 As 2 ; a=4.5352(2) Å, c=23.7221(11) Å for EuAg 4 As 2 ; a=4.7404(4) Å, c=25.029(2) Å for SrAg 4 Sb 2 ; a=4.7239(3) Å, c=24.689(2) Å for EuAg 4 Sb 2 ), which can be derived from the trigonal CaAl 2 Si 2 -type structure of the isoelectronic zinc-containing pnictides AZn 2 Pn 2 by insertion of additional Ag atoms into trigonal planar sites within [M 2 Pn 2 ] 2− slabs built up of edge-sharing tetrahedra. Band structure calculations on SrAg 4 As 2 and SrAg 4 Sb 2 revealed that these charge-balanced Zintl phases actually exhibit no gap at the Fermi level and are predicted to be semimetals. - Graphical abstract: SrAg 4 As 2 and related pnictides adopt a CaCu 4 P 2 -type structure in which additional Ag atoms enter trigonal planar sites within slabs built from edge-sharing tetrahedra. Highlights: ► AAg 4 Pn 2 are the first Ag-containing members of the CaCu 4 P 2 -type structure. ► Ag atoms are stuffed in trigonal planar sites within CaAl 2 Si 2 -type slabs. ► Ag–Ag bonding develops through attractive d 10 –d 10 interactions.

Preparation and oxidation resistance of single crystalline β-Zn{sub 4}Sb{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu, Hong-xia; Deng, Shu-ping [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500 (China); Li, De-cong [Photoelectric Engineering College, Yunnan Open University, Kunming 650500 (China); Shen, Lan-xian; Cheng, Feng; Wang, Jin-song [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500 (China); Deng, Shu-kang, E-mail: skdeng@126.com [Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500 (China)

2016-11-01

This study prepared a Zn-rich single crystal β-Zn{sub 4}Sb{sub 3} using a Sn flux method based on the stoichiometric ratios of Zn{sub 4.4}Sb{sub 3}Sn{sub 3}. The oxidation resistance of the sample was determined by exploring the effects of heat treatment in air on electrical transport properties and thermal stability, which is of practical importance in the application of the material at high temperatures. Results showed that the prepared sample possessed high electrical transport properties, with a high power factor of 1.67×10{sup −3} W m{sup −1} K{sup −2} at 563 K. The heat treatment in air weakened the electrical conductivity of the single crystalline β-Zn{sub 4}Sb{sub 3}, whereas the Seebeck coefficients were rarely independent of the annealing condition. Eventually, the power factor obtained after the first heating at 523 K for 4 h became comparable to that of the as-prepared sample, although it decreased after the second heating at 573 K for 5 h. Nevertheless, the single crystalline β-Zn{sub 4}Sb{sub 3} still possessed a good thermal stability after the heat treatment process.

Enhanced electrical transport and thermoelectric properties in Ni doped Cu3SbSe4

Science.gov (United States)

Kumar, Aparabal; Dhama, P.; Das, Anish; Sarkar, Kalyan Jyoti; Banerji, P.

2018-05-01

In this study, we report the enhanced thermoelectric performance of Cu3SbSe4 by Ni doping at Cu site. Cu3-xNixSbSe4 (x = 0, 0.01, 0.03, 0.05) were prepared by melt growth, ball milling followed by spark plasma sintering. Structural characterization, phase analysis and surface morphology were carried out using X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Electrical and thermal properties of all the samples were investigated in the temperature range 300 - 650 K. Decrease in electrical resistivity with Ni doping due to increase in carrier concentration with enhanced Seebeck coefficient via increase in density of state near the Fermi level gives a remarkably high power factor. At the same time, thermal conductivity was found to decrease due to increased carrier-phonon scattering and acoustic phonon scattering. Consequently, a remarkable enhancement in the thermoelectric figure of merit (ZT˜ 0.65) of Cu3-xNixSbSe4 was achieved for x = 0.01 sample. Thus, Ni doping is an effective approach to improve the efficiency of Cu3SbSe4.

Oyonite, Ag3Mn2Pb4Sb7As4S24, a New Member of the Lillianite Homologous Series from the Uchucchacua Base-Metal Deposit, Oyon District, Peru

Directory of Open Access Journals (Sweden)

Luca Bindi

2018-05-01

Full Text Available The new mineral species oyonite, ideally Ag3Mn2Pb4Sb7As4S24, has been discovered in the Uchucchacua base-metal deposit, Oyon district, Catajambo, Lima Department, Peru, as very rare black metallic subhedral to anhedral crystals, up to 100 μm in length, associated with orpiment, tennantite/tetrahedrite, menchettiite, and other unnamed minerals of the system Pb-Ag-Sb-Mn-As-S, in calcite matrix. Its Vickers hardness (VHN100 is 137 kg/mm2 (range 132–147. In reflected light, oyonite is weakly to moderately bireflectant and weakly pleochroic from dark grey to a dark green. Internal reflections are absent. Reflectance values for the four COM wavelengths [Rmin, Rmax (% (λ in nm] are: 33.9, 40.2 (471.1; 32.5, 38.9 (548.3, 31.6, 38.0 (586.6; and 29.8, 36.5 (652.3. Electron microprobe analysis gave (in wt %, average of 5 spot analyses: Cu 0.76 (2, Ag 8.39 (10, Mn 3.02 (7, Pb 24.70 (25, As 9.54 (12, Sb 28.87 (21, S 24.30 (18, total 99.58 (23. Based on 20 cations per formula unit, the chemical formula of oyonite is Cu0.38Ag2.48Mn1.75Pb3.79Sb7.55As4.05S24.12. The main diffraction lines are (d in Å, hkl and relative intensity: 3.34 (−312; 40, 3.29 (−520; 100, 2.920 (−132; 40, 2.821 (−232; 70, 2.045 (004; 50. The crystal structure study revealed oyonite to be monoclinic, space group P21/n, with unit-cell parameters a = 19.1806 (18, b = 12.7755 (14, c = 8.1789 (10 Å, β = 90.471 (11°, V = 2004.1 (4 Å3, Z = 2. The crystal structure was refined to a final R1 = 0.032 for 6272 independent reflections. Oyonite belongs to the Sb-rich members of the andorite homeotypic sub-series within the lillianite homologous series. The name oyonite is after the Oyon district, Lima Department, Peru, the district where the type locality (Uchucchacua mine is located.

The characterization of Co xZn7-xSb2O12 spinel obtained by the pechini method

Directory of Open Access Journals (Sweden)

Deiby Santos Gouveia

2005-06-01

Full Text Available Oxides with spinel structures have been studied for many decades as they have been used in a variety of applications like pigments and refractories. They have also been used as a model structure to evaluate the relative stability of ions in octahedral and tetrahedral sites. Zinc- antimony spinels (Zn7Sb2O12 were synthesized by the Pechini method and the cation Zn2+ was substituted by Co2+, taking into consideration the stoichiometry of Co xZn7-xSb2O12 (x = 0 - 7. Characterization of the thermal properties of pyrolyzed powders was carried out with a TG/DTA analyzer, and mass losses were determined as a function of the cobalt content in the resin. The powders were calcined at temperatures in the range 600 to 1000 °C and characterized by XRD, BET and IR spectroscopy. Maximum cristalinity was obtained in powders calcined at 1000 °C. Materials with x = 5 - 7 revealed the presence of a secondary phase (Co, ZnSb2O6. Infrared analysis facilitated in the determination of the possible sites of Zn2+, Co2+ and Sb2+ ions in the lattice.

Atomic structure determination of InSb(100)c(4x4) and c(8x2)phases by X-ray photoelectron diffraction

International Nuclear Information System (INIS)

Carvalho, V.E. de; Soares, E.A.; Magalhaes, M.R.P.; Paniago, R.; Siervo, A. de; Landers, R.

2004-01-01

Full text: The (100) surfaces of III-V compound semiconductors exhibit a variety of surface reconstructions that have attracted a lot of attention because of their importance in both homo epitaxial and heteroepitaxial growth. In the special case of the narrow bandgap InSb compound semiconductor its potential application in high-speed electronic and optoelectronic devices has encourage many studies of its (100) surface atomic structure. Among the reconstructions presented by the InSb(100) surface two of them have received more attention, that is, the observed well-ordered In-rich c(8x2) and Sb terminated c(4x4) surfaces. The c(8x2) structure can be obtained by exposing the surface to low energy ion bombardment and annealing, whereas the c(4x4) structure involves the chemisorption of Sb onto an already Sb-terminated surface. These two structures have been studied mainly by scanning tunneling microscopy (STM) and surface X-ray diffraction (SXRD) techniques and all the proposed models are based on the occurrence of group III (and/or V) blocks of dimmers occupying sites on the top or at subsurface layer. However, there are still difficulties in determining either the exact number of atoms in each dimmer or the number of dimmers in each block. With the goal of getting a better structure determination of the InSb(100) surface phases a photoelectron diffraction experiment (XPD) was carried out at LNLS where synchrotron and Al-K α radiations have been used. In the present work, the experimental and preliminary results of structure determination for both In Sn(100)c(8x2) and InSb(100)c(4x4) phases will be presented and discussed. (author)

The crystal structure of ferdowsiite Ag8Sb4(As,Sb)4S16 and its relations to other ABX2 (A=Ag; B=As,Sb,Bi; X=S,Se) structures

DEFF Research Database (Denmark)

Makovicky, Emil; Topa, Dan

2014-01-01

arsenic. The crystal structure of ferdowsiite is a superstructure of a PbS like motif. The {100} planes of the PbS-like substructure are the (105̅), (301) and (010) planes in terms of the ferdowsiite lattice. The structure contains zig-zag chains of Sb1 connected via short Sb-S bonds and flanked by (Sb...

Centrosymmetry vs noncentrosymmetry in La{sub 2}Ga{sub 0.33}SbS{sub 5} and Ce{sub 4}GaSbS{sub 9} based on the interesting size effects of lanthanides: Syntheses, crystal structures, and optical properties

Energy Technology Data Exchange (ETDEWEB)

Zhao, Hua-Jun, E-mail: cszzl772002@yeah.net [Laboratory of Applied Research on the Characteristic Resources in the North of Guizhou Province, School of Chemistry and Chemical Engineering, Zunyi Normal College, Zunyi, Guizhou 563002 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2016-05-15

Two new quaternary sulfides La{sub 2}Ga{sub 0.33}SbS{sub 5} and Ce{sub 4}GaSbS{sub 9} have been prepared from stoichiometric elements at 1223 K in an evacuated silica tube. Interestingly, La{sub 2}Ga{sub 0.33}SbS{sub 5} crystallizes in the centrosymmetric structure, while Ce{sub 4}GaSbS{sub 9} crystallizes in the noncentrosymmetric structure, which show obvious size effects of lanthanides on the crystal structures of these two compounds. Ce{sub 4}GaSbS{sub 9} belongs to RE{sub 4}GaSbS{sub 9} (RE=Pr, Nd, Sm, Gd–Ho) structure type with a=13.8834(9) Å, b=14.3004(11) Å, c=14.4102(13) Å, V=2861.0(4) Å{sup 3}. The structure features infinite chains of [Ga{sub 2}Sb{sub 2}S{sub 11}{sup 10–}]{sub ∞} propagating along a direction separated by Ce{sup 3+} cations and S{sup 2−} anions. La{sub 2}Ga{sub 0.33}SbS{sub 5} adopts the family of La{sub 4}FeSb{sub 2}S{sub 10}-related structure with a=7.5193(6) Å, c=13.4126(17) Å, V=758.35(13) Å{sup 3}. Its structure is built up from the alternate stacking of La/Sb/S and La/Ga/S 2D building blocks. The La/Sb/S slabs consist of teeter-totter chains of Sb1S{sub 4} seesaws, which are connected via sharing the apexes of μ{sub 4}-S1. Moreover, La1 is positionally disordered with Sb1 and stabilized in a bicapped trigonal prismatic coordination sphere. Between these La/Sb/S slabs, La2S{sub 8} square antiprisms are connected via edge-sharing into 2D building blocks, creating tetrahedral sites partially occupied by the Ga1 atoms. UV/Vis diffuse reflectance spectroscopy study shows that the optical gap of La{sub 2}Ga{sub 0.33}SbS{sub 5} is about 1.76 eV. - Graphical abstract: Two new quaternary sulfides La{sub 2}Ga{sub 0.33}SbS{sub 5} and Ce{sub 4}GaSbS{sub 9} have been prepared by solid-state reactions. Ce{sub 4}GaSbS{sub 9} crystallizes in RE{sub 4}GaSbS{sub 9} (RE=Pr, Nd, Sm, Gd–Ho) structure type, while La{sub 2}Ga{sub 0.33}SbS{sub 5} belongs to the family of La{sub 4}FeSb{sub 2}S{sub 10}-related structure and exhibits an

A Novel Framework Antimony (III) Phosphate: Synthesis and Structure of NaSb 3O 2(PO 4) 2

Science.gov (United States)

Adair, Brian A.; de Delgado, Graciela Díaz; Miguel Delgado, J.; Cheetham, Anthony K.

2000-04-01

The antimony (III) phosphate, NaSb3O2(PO4)2, is a framework structure built from SbIII and PV centers; orthorhombic, space group Pca21 (No. 29), a=13.944(3), b=6.6822(13), c=20.886(4) Å, V=1946.1(7) Å3, Z=8. Stereochemically active lone pairs of electrons associated with SbIIIO5 and SbIIIO4 polyhedra point into eight-ring channels, approximately 5×7 Å2, which dominate the architecture of the title compound. Charge-compensating sodium cations occupy the remaining space in the channels.

Martensitic phase transformations and magnetocaloric effect in Al co-sputtered Ni–Mn–Sb alloy thin films

International Nuclear Information System (INIS)

Akkera, Harish Sharma; Choudhary, Nitin; Kaur, Davinder

2015-01-01

Highlights: • The Al content leads to a increase in the martensitic transformation temperature. • A maximum ΔS M = 23 mJ/cm 3 K at 300 K was observed in the N 49.8 Mn 32.97 Al 4.43 Sb 12.8 . • The refrigeration capacity RC = 64.4 mJ/cm 3 at 2 T for N 49.8 Mn 32.97 Al 4.43 Sb 12.8 film. - Abstract: We systematically investigated the influence of aluminium (Al) content on the martensitic transformations and magnetocaloric effect (MCE) in Ni–Mn–Sb ferromagnetic shape memory alloy (FSMA) thin films. The temperature-dependent magnetization (M–T) and resistance (R–T) results displayed a monotonic increase in martensitic transformation temperature (T M ) with increasing Al content. From the isothermal magnetization (M–H) curves, a large magnetic entropy change (ΔS M ) of 23 mJ/cm 3 K was observed in N 49.8 Mn 32.97 Al 4.43 Sb 12.8 . A remarkable enhancement of MCE could be attributed to the significant change in the magnetization of Ni–Mn–Sb films with increasing Al content. Furthermore, a high refrigerant capacity (RC) was observed in Ni–Mn–Sb–Al thin films as compared to pure Ni–Mn–Sb. The substitution of Al for Mn in Ni–Mn–Sb thin films with field induced MCE are potential candidates for micro length scale magnetic refrigeration applications where low magnetic fields are desirable

Draft genome sequence of a monokaryotic model brown-rot fungus Postia (Rhodonia) placenta SB12

Science.gov (United States)

Jill Gaskell; Phil Kersten; Luis F. Larrondo; Paulo Canessa; Diego Martinez; David Hibbett; Monika Schmoll; Christian P. Kubicek; Angel T. Martinez; Jagjit Yadav; Emma Master; Jon Karl Magnuson; Debbie Yaver; Randy Berka; Kathleen Lail; Cindy Chen; Kurt LaButti; Matt Nolan; Anna Lipzen; Andrea Aerts; Robert Riley; Kerrie Barry; Bernard Henrissat; Robert Blanchette; Igor V. Grigoriev; Dan Cullen

2017-01-01

We report the genome of Postia (Rhodonia) placenta MAD-SB12, a homokaryotic wood decay fungus (Basidiomycota, Polyporales). Intensively studied as a representative brown rot decayer, the gene complement is consistent with the rapid depolymerization of cellulose but not lignin.

New sulfido antimonates of the heavy alkali metals. Synthesis, crystal structure and chemical bonding of (K/Rb/Cs){sub 3}SbS{sub 3} and Cs{sub 3}SbS{sub 4} . H{sub 2}O; Neue Sulfido-Antimonate der schweren Alkalimetalle. Synthese, Kristallstruktur und chemische Bindung von (K/Rb/Cs){sub 3}SbS{sub 3} und Cs{sub 3}SbS{sub 4} . H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Schindler, Lisa V.; Schwarz, Michael; Roehr, Caroline [Freiburg Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2013-12-15

The new sulfido antimonates(III) (Rb/Cs){sub 3}SbS{sub 3} were prepared from the alkali metal sulfides Rb{sub 2}S/Cs{sub 2}S{sub 2} and elemental antimony and sulfur or Sb{sub 2}S{sub 3} at reaction temperatures of about 700 C. The known isotypic potassium compound was similarly synthesized from the elements. The structures of the light-yellow crystals were refined using single-crystal X-ray data. Both compounds are isotypic to the respective Na salt forming the Na{sub 3}AsS{sub 3} structure type (cubic, space group P2{sub 1}3, K/Rb/Cs: a = 947.21(7)/982.28(5)/1025.92(5) pm, Z = 4, R1 = 0.0159/0.0560/0.0582). The {psi}-tetrahedral SbS{sub 3}{sup 3-} anions with Sb-S bond lengths of 242 pm are arranged in a cubic face centered packing, in which the three crystallographically different A{sup +} cations occupy the tetrahedral and octahedral voids, overall exhibiting a distorted octahedral sulfur coordination. The chemical bonding and the characteristics of the stereochemically active lone electron pair have been investigated by means of FP-LAPW band structure calculations. Needle-shaped crystals of the monohydrate of the antimony(V) salt Cs{sub 3}SbS{sub 4} . H{sub 2}O were obtained from a suspension of Sb{sub 2}O{sub 3}, CsOH and elemental sulfur. Cs{sub 3}SbS{sub 4} . H{sub 2}O crystallizes in a new structure type (monoclinic, space group P2{sub 1}/c, a = 987.17(10), b = 994.83(7), c = 1600.46(14) pm, {beta} = 126.895(8) , Z = 4, R1 = 0.0234). As expected, the Sb-S distances (233.1-234.7 pm) in the nearly ideally tetrahedral anion SbS{sub 4}{sup 3-} are considerably shorter than in the antimonates(III) but match the bond lengths in the anhydrous sulfido antimonate(V) Cs{sub 3}SbS{sub 4}. Due to their similar fcc-like anion packing and the stereochemically active lone electron pair of Sb in the antimonates(III), the whole series of compounds A{sub 3}Sb{sup III,V}S{sub 3/4} shows a uniform structure relation, which is elucidated using crystallographic group

Redundant Sb condensation on GaSb epilayers grown by molecular beam epitaxy during cooling procedure

International Nuclear Information System (INIS)

Arpapay, B.; Şahin, S.; Arıkan, B.; Serincan, U.

2014-01-01

The effect of four different cooling receipts on the surface morphologies of unintentionally-doped GaSb epilayers on GaSb (100) substrates grown by molecular beam epitaxy is reported. Those receipts include three different Sb beam equivalent pressure (BEP) levels and two different termination temperatures. Surface morphologies of epilayers were examined by wet etching, surface profiler, atomic force microscopy, scanning electron microscopy and Raman spectroscopy. The results demonstrate that during the cooling period, a Sb BEP of 4.00 × 10 −4 Pa at a termination temperature of 400 °C induces a smooth surface without Sb condensation whereas same Sb BEP at a termination temperature of 350 °C forms a 300 nm thick Sb layer on the surface. In addition, it is revealed that by applying a wet etching procedure and using a surface profiler it is possible to identify this condensed layer from the two-sloped feature of mesa profile. - Highlights: • Sb beam flux termination temperature is crucial for redundant Sb condensation. • Sb beam flux level has a role on the thickness of redundant condensed Sb layer. • Redundant Sb layer thickness can be measured by two-sloped mesa structure

High-spin, multiparticle isomers in 121,123Sb

International Nuclear Information System (INIS)

Jones, G. A.; Walker, P. M.; Podolyak, Zs.; Cullen, I. J.; Garnsworthy, A. B.; Liu, Z.; Thompson, N. J.; Williams, S. J.; Zhu, S.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Seweryniak, D.; Carroll, J. J.; Chakrawarthy, R. S.; Hackman, G.; Chowdhury, P.; Dracoulis, G. D.; Lane, G. J.; Kondev, F. G.

2008-01-01

Isomers in near-spherical Z=51, antimony isotopes are reported here for the first time using fusion-fission reactions between 27 Al and a pulsed 178 Hf beam of energy, 1150 MeV. γ rays were observed from the decay of isomeric states with half-lives, T 1/2 =200(30) and 52(3)μs, and angular momenta I=((25/2)) and I π =(23/2) + , in 121,123 Sb, respectively. These states are proposed to correspond to ν(h (11/2) ) 2 configurations, coupled to an odd d (5/2) or g (7/2) proton. Nanosecond isomers were also identified at I π =(19/2) - [T 1/2 =8.5(5) ns] in 121 Sb and I π =((15/2) - ) [T 1/2 =37(4) ns] in 123 Sb. Information on spins and parities of states in these nuclei was obtained using a combination of angular correlation and intensity-balance measurements. The configurations of states in these nuclei are discussed using a combination of spin/energy systematics and shell-model calculations for neighboring tin isotones and antimony isotopes

Density functional simulations of Sb-rich GeSbTe phase change alloys

OpenAIRE

Gabardi, S; Caravati, S; Bernasconi, M; Parrinello, M

2012-01-01

We generated models of the amorphous phase of Sb rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge 1Sb 1Te 1 and Ge 2Sb 4Te 5. Comparison with previous results on the most studied Ge 2Sb 2Te 5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high fr...

27 CFR 4.72 - Metric standards of fill.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Metric standards of fill. 4.72 Section 4.72 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Standards of Fill for Wine § 4.72 Metric...

Enhanced thermoelectric performance with participation of F-electrons in β-Zn4Sb3

International Nuclear Information System (INIS)

Liu, Mian; Qin, Xiaoying; Liu, Changsong; Li, Xiyu; Yang, Xiuhui

2014-01-01

Highlights: • Find an effective route to enhance the thermoelectric figure of merit of β-Zn 4 Sb 3 . • Provide the corresponding theoretical predictions. • Investigated the effects of doping Ce and Pr in β-Zn 4 Sb 3 . -- Abstract: The effects of rare-earth element impurities Ce and Pr on the electronic structure and thermoelectric properties of β-Zn 4 Sb 3 were investigated by performing self-consistent ab initio electronic structure calculations within density functional theory and solving the Boltzmann transport equations within the relaxation time approximation. The results demonstrated that these rare-earth element impurities with f orbitals could introduce giant sharp resonant peaks in the density of states (DOS) near the host valence band maximum in energy. And these deliberately engineered DOS peaks result in a sharp increase of the room-temperature Seebeck coefficient and power factor from those of impurity-free system by a factor of 100 and 22, respectively. Additionally, with the simultaneous declining of carrier thermal conductivity, a potential 5-fold increase at least with Ce doping and more than 3 times increase with Pr doping in the thermoelectric figure of merit of β-Zn 4 Sb 3 at room temperature are achieved. The effective DOS restructuring strategy opens up new opportunities for thermoelectric power generation and waste heat recovery at large scale

Surface passivation of GaInAsSb photodiodes with thioacetamide

Energy Technology Data Exchange (ETDEWEB)

Salesse, A.; Joullie, A.; Chevrier, F.; Cuminal, Y.; Ferblantier, G.; Christol, P. [Institut d' Electronique du Sud (IES-CEM2), UMR CNRS 5507, Case 067, Universite Montpellier 2, 34 095 Montpellier Cedex 05 (France); Calas, P. [UMR CNRS 5073 CHIMIE, Case 017, Universite Montpellier 2, 34 095 Montpellier Cedex 05 (France); Nieto, J. [Instituto de Investigacion en Comunicacion Optica (IICO), Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi (Mexico)

2007-04-15

AlGaAsSb/GaInAsSb heterojunction mesa photodiodes having 2.2 {mu}m cutoff wavelength, grown by MBE on (p) GaSb substrates, have been passivated using thioacetamide CH{sub 4}CSNH{sub 2} and ammonium sulphide (NH{sub 4}){sub 2}S. Superior characteristics were obtained from devices processed with thioacetamide in acid medium (pH=2.4). At room temperature the surface leakage currents were suppressed, and the photodiodes showed R{sub 0}A product as high as 16 {omega}cm{sup 2} and detectivity D{sup *}(2 {mu}m,0 V){proportional_to}10{sup 10} cmHz{sup 1/2}W{sup -1}. A model explaining sulfuration mechanisms with thioacetamide and (NH{sub 4}){sub 2}S is proposed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Nanocrystalline GaSbO{sub 4} with high surface area prepared via a facile hydrothermal method and its photocatalytic activity study

Energy Technology Data Exchange (ETDEWEB)

Fu Yanghe; Xue Hun; Qin Meng; Liu Ping; Fu Xianzhi [Research Institute of Photocatalysis, Fujian Provincial Key Laboratory of Photocatalysis - State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002 (China); Li Zhaohui, E-mail: zhaohuili1969@yahoo.com [Research Institute of Photocatalysis, Fujian Provincial Key Laboratory of Photocatalysis - State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002 (China)

2012-05-05

Graphical abstract: Nanocrystalline GaSbO{sub 4} prepared via a facile hydrothermal method possesses large specific surface area and exhibits photocatalytic activity for the degradations of salicylic acid and acetone. Highlights: Black-Right-Pointing-Pointer Facile hydrothermal method to nanocrystalline GaSbO{sub 4} with large surface area. Black-Right-Pointing-Pointer GaSbO{sub 4} shows photocatalytic activity for the degradations of salicylic acid and acetone. Black-Right-Pointing-Pointer The photocatalytic mechanism of GaSbO{sub 4} was proposed based on the ESR result. - Abstract: Nanocrystalline GaSbO{sub 4} with small particle size and large BET specific area was successfully prepared via a facile hydrothermal method from Sb{sub 2}O{sub 5}. The influence of the reaction pH on the formation of the final product was investigated. The obtained sample was characterized by X-ray diffraction (XRD), N{sub 2}-sorption BET surface area, UV-vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity for the degradations of salicylic acid and acetone over nanocrystalline GaSbO{sub 4} under UV irradiations was for the first time revealed. Based on the electron spin resonance (ESR) result, the reactive species involved in the photocatalytic reaction over nanocrytalline GaSbO{sub 4} are determined to be HO{center_dot} and O{sub 2}{sup -}{center_dot}. The photocatalytic mechanism of GaSbO{sub 4} was proposed.

Zr3NiSb7: a new antimony-enriched ZrSb2 derivative

Directory of Open Access Journals (Sweden)

V. Romaka

2008-08-01

Full Text Available Single crystals of trizirconium nickel heptaantimonide were synthesized from the constituent elements by arc-melting. The compound crystallizes in a unique structure type and belongs to the family of two-layer structures. All crystallographically unique atoms (3 × Zr, 1 × Ni and 7 × Sb are located at sites with m symmetry. The structure contains `Zr2Ni2Sb5' and `Zr4Sb9' fragments and might be described as a new ZrSb2 derivative with a high Sb content.

Effects of antimony (Sb) on electron trapping near SiO{sub 2}/4H-SiC interfaces

Energy Technology Data Exchange (ETDEWEB)

Mooney, P. M.; Jiang, Zenan; Basile, A. F. [Physics Department, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Zheng, Yongju; Dhar, Sarit [Physics Department, Auburn University, Auburn, Alabama 36849 (United States)

2016-07-21

To investigate the mechanism by which Sb at the SiO{sub 2}/SiC interface improves the channel mobility of 4H-SiC MOSFETs, 1 MHz capacitance measurements and constant capacitance deep level transient spectroscopy (CCDLTS) measurements were performed on Sb-implanted 4H-SiC MOS capacitors. The measurements reveal a significant concentration of Sb donors near the SiO{sub 2}/SiC interface. Two Sb donor related CCDLTS peaks corresponding to shallow energy levels in SiC were observed close to the SiO{sub 2}/SiC interface. Furthermore, CCDLTS measurements show that the same type of near-interface traps found in conventional dry oxide or NO-annealed capacitors are present in the Sb implanted samples. These are O1 traps, suggested to be carbon dimers substituted for O dimers in SiO{sub 2}, and O2 traps, suggested to be interstitial Si in SiO{sub 2}. However, electron trapping is reduced by a factor of ∼2 in Sb-implanted samples compared with samples with no Sb, primarily at energy levels within 0.2 eV of the SiC conduction band edge. This trap passivation effect is relatively small compared with the Sb-induced counter-doping effect on the MOSFET channel surface, which results in improved channel transport.

The ferromagnetic Kondo-lattice compound SmFe sub 4 P sub 1 sub 2

CERN Document Server

Takeda, N

2003-01-01

We report on the magnetic properties of a filled skutterudite compound, SmFe sub 4 P sub 1 sub 2. Magnetic susceptibility and specific heat measurements revealed a ferromagnetic transition at 1.6 K. The temperature dependence of the electrical resistivity exhibits a Kondo-lattice behaviour and the electronic specific heat coefficient attains values as large as 370 mJ mol sup - sup 1 K sup - sup 2. This compound is thereby the first Sm-based heavy-fermion system found with a ferromagnetic ground state. The Kondo temperature is estimated to be about 30 K. (letter to the editor)

Density functional simulations of Sb-rich GeSbTe phase change alloys

International Nuclear Information System (INIS)

Gabardi, S; Bernasconi, M; Caravati, S; Parrinello, M

2012-01-01

We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge 1 Sb 1 Te 1 and Ge 2 Sb 4 Te 5 . Comparison with previous results on the most studied Ge 2 Sb 2 Te 5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm -1 are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge 2 Sb 2 Te 5 . All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

Density functional simulations of Sb-rich GeSbTe phase change alloys

Science.gov (United States)

Gabardi, S.; Caravati, S.; Bernasconi, M.; Parrinello, M.

2012-09-01

We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge1Sb1Te1 and Ge2Sb4Te5. Comparison with previous results on the most studied Ge2Sb2Te5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm-1 are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge2Sb2Te5. All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

Radiation measurements by pn junction InSb detector at the temperature from 4.2 K to 115 K

International Nuclear Information System (INIS)

Kanno, Ikuo; Yoshihara, Fumiki; Nouchi, Ryo; Sugiura, Osamu; Murase, Yasuhiro; Nakamura, Tatsuya; Katagiri, Masaki

2003-01-01

We fabricated the pn junction-type detectors on a p-type InSb substrate. Both sides of the InSb substrate were etched using a mixture of nitric and lactic acids. On the top side surface, Sn and Al were deposited by heat evaporation and then the Sn was diffused into the p-type InSb by lamp annealing and resulted in the n-type layer. Based on the confirmation of the performance of the InSb detector at temperatures of 0.5 K and 4.2 K, we concentrated on the measurement of alpha particles by the pm junction-type InSb detectors at higher operating temperatures of up to 115 K. The InSb detector showed a wide temperature operating range. We can conclude that all of the voltage was induced slowly by the holes at 4.2 K and mainly as a result of electrons at 77 K. (T. Tanaka)

Theoretical study of defects Cu{sub 3}SbSe{sub 4}: Search for optimum dopants for enhancing thermoelectric properties

Energy Technology Data Exchange (ETDEWEB)

Do, Dat T., E-mail: dodat@msu.edu; Mahanti, S.D., E-mail: mahanti@pa.msu.edu

2015-03-15

Highlights: • We present the first systematic study of defects in Cu{sub 3}SbSe{sub 4}. • Possible n-type and p-type dopants are suggested for Cu and Sb site. • Transition-metal substitutions on Sb potentially improve thermoelectric properties. • Transition-metal substitutions on Se strongly distort local crystal geometry. • p-type behavior of as synthesized Cu{sub 3}SbSe{sub 4} is most likely due to Cu. - Abstract: Cu{sub 3}SbSe{sub 4} is a promising thermoelectric material due to high thermopower (>400μV/K) at 300 K and higher. Although it has a simple crystal structure derived from zinc blende structure, previous work has shown that the physics of band gap formation is quite subtle due to the importance of active lone pair (5s{sup 2}) of Sb and the non-local exchange interaction between these and Se 5p electrons. Since for any application of semiconductors understanding the properties of defects is essential, we discuss the results of a systematic study of several point defects in Cu{sub 3}SbSe{sub 4} including vacancies and substitutions for each of the components. First principles calculations using density functional theory show that among variety of possible dopants, p-type doping can be done by substituting Sb with group IV elements including Sn, Ge, Pb and Ti and n-type doping can be done by replacing Cu by Mg, Zn. Doping at the Se site appears to be rather difficult. Electronic structure calculations also suggest that the p-type behavior seen in nominally pure Cu{sub 3}SbSe{sub 4} is most likely due to Cu vacancy rather than Se vacancy.

The influence of Sn Additions on the Thermoelectric and Transport Properties of FeSb2Te-based Ternary Skutterudites

Czech Academy of Sciences Publication Activity Database

Navrátil, Jiří; Plecháček, T.; Drašar, Č.; Kucek, V.; Laufek, František; Černošková, E.; Beneš, L.; Vlček, Milan

2016-01-01

Roč. 45, č. 6 (2016), s. 2904-2913 ISSN 0361-5235 R&D Projects: GA ČR(CZ) GA13-33056S Institutional support: RVO:61389013 ; RVO:68378271 Keywords : effective medium theory * FeSb2Te * Sn - addition Subject RIV: CA - Inorganic Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 1.579, year: 2016

Phase diagram of the Sb-Se-I system and thermodynamic properties of SbSeI

International Nuclear Information System (INIS)

Aliev, Z.S.; Musaeva, S.S.; Babanly, D.M.; Shevelkov, A.V.; Babanly, M.B.

2010-01-01

The Sb-Se-I system was investigated by using the DTA and XRD analyses and EMF measurements with an antimony electrode. The T-x diagram of the binary Sb-I system was accurately redefined. A number of polythermal sections and the projection of the liquidus surface were constructed. The fields of the primary crystallization, as well as the types and coordinates of non- and monovariant equilibria were determined. It is shown that the quasi-binary sections Sb 2 Se 3 -SbI 3 , Sb-SbSeI, SbI 3 -Se, and SbSeI-Se triangulate the Sb-Se-I system, leading to five independent subsystems. A broad area of immiscibility, that overlaps a certain part of the antimony primary crystallization field, was found. From the EMF measurements, the partial molar functions of antimony (ΔG-bar, ΔH-bar, ΔS-bar) as well as standard integral thermodynamic functions of SbSeI were calculated. The latter were found to have the following values: ΔG f,298 0 =-80.12±1.81kJ/mol; ΔH f,298 0 =-77.3±1.8kJ/mol; S 298 0 =155.2±9.5J/(molK).

Phase diagram of the Sb-Se-I system and thermodynamic properties of SbSeI

Energy Technology Data Exchange (ETDEWEB)

Aliev, Z S; Musaeva, S S; Babanly, D M [Baku State University, General and Inorganic Chemistry Department (Azerbaijan); Shevelkov, A.V., E-mail: shev@inorg.chem.msu.r [Moscow Lomonosov State University, Chemistry Department (Russian Federation); Babanly, M.B., E-mail: Babanly_mb@rambler.r [Baku State University, General and Inorganic Chemistry Department (Azerbaijan)

2010-09-03

The Sb-Se-I system was investigated by using the DTA and XRD analyses and EMF measurements with an antimony electrode. The T-x diagram of the binary Sb-I system was accurately redefined. A number of polythermal sections and the projection of the liquidus surface were constructed. The fields of the primary crystallization, as well as the types and coordinates of non- and monovariant equilibria were determined. It is shown that the quasi-binary sections Sb{sub 2}Se{sub 3}-SbI{sub 3}, Sb-SbSeI, SbI{sub 3}-Se, and SbSeI-Se triangulate the Sb-Se-I system, leading to five independent subsystems. A broad area of immiscibility, that overlaps a certain part of the antimony primary crystallization field, was found. From the EMF measurements, the partial molar functions of antimony ({Delta}G-bar, {Delta}H-bar, {Delta}S-bar) as well as standard integral thermodynamic functions of SbSeI were calculated. The latter were found to have the following values: {Delta}G{sub f,298}{sup 0}=-80.12{+-}1.81kJ/mol; {Delta}H{sub f,298}{sup 0}=-77.3{+-}1.8kJ/mol; S{sub 298}{sup 0}=155.2{+-}9.5J/(molK).

Polaronic transport and thermoelectricity in Fe1 -xCoxSb2S4 (x =0 , 0.1, and 0.2)

Science.gov (United States)

Liu, Yu; Kang, Chang-Jong; Stavitski, Eli; Du, Qianheng; Attenkofer, Klaus; Kotliar, G.; Petrovic, C.

2018-04-01

We report a study of Co-doped berthierite Fe1 -xCoxSb2S4 (x =0 , 0.1, and 0.2). The alloy series of Fe1 -xCoxSb2S4 crystallize in an orthorhombic structure with the Pnma space group, similar to FeSb2, and show semiconducting behavior. The large discrepancy between activation energy for conductivity, Eρ (146 ˜270 meV ), and thermopower, ES (47 ˜108 meV ), indicates the polaronic transport mechanism. Bulk magnetization and heat-capacity measurements of pure FeSb2S4 (x =0 ) exhibit a broad antiferromagnetic transition (TN=46 K ) followed by an additional weak transition (T*=50 K ). Transition temperatures (TN and T*) slightly decrease with increasing Co content x . This is also reflected in the thermal conductivity measurement, indicating strong spin-lattice coupling. Fe1 -xCoxSb2S4 shows relatively high value of thermopower (up to ˜624 μ V K-1 at 300 K) and thermal conductivity much lower when compared to FeSb2, a feature desired for potential applications based on FeSb2 materials.

Synthesis and characterisation of YbPdSb

Energy Technology Data Exchange (ETDEWEB)

Haines, Charles R.S.; Brown, Philip A.C.; Grosche, Friedrich M. [Department of Physics, Cavendish Laboratory, University of Cambridge (United Kingdom)

2016-07-01

The intermetallic compound YbPdSb can form in two structures: the low temperature (LT) half-Heusler phase, in which the Yb atoms form a frustrated fcc structure, and the high temperature (HT) Pnma modification. We have prepared phase pure samples of both structures and report resistivity, magnetisation and heat capacity measurements on both. The LT phase is a Kondo lattice system showing large-moment Curie-Weiss paramagnet behaviour without any phase transition anomalies down to the lowest temperatures measured. The resistivity is rather insensitive to temperature from room temperature down to ∝50 K where it decreases steeply with further cooling. By contrast, in the HT phase the magnetic susceptibility displays weak temperature dependence and the resistivity falls with decreasing temperature in the way expected of a weakly correlated metal. These findings suggest that in contrast to the electronic state in the LT structure, the 4f-shell of Yb is completely filled in the HT structure of YbPdSb, presenting an interesting opportunity to study the interplay between lattice and electronic structure within the same compound.

Synthesis and Study of Electrical Properties of SbTeI

Directory of Open Access Journals (Sweden)

Harish K. Dubey

2014-01-01

Full Text Available Needle shaped SbTeI crystals were obtained by solid state reaction. Electrical resistance was measured in the temperature range of 4 K to 550 K. SbTeI shows a metallic behavior from 4 K to 300 K, and at higher temperature (>300 K, it shows semiconducting behavior. Unlike SbSI, this material shows almost zero resistance around 550 K. It shows a piezoelectric behavior with a capacitance of 717 pF and its carrier density and nobilities are found to be 2.12 × 1016 cm−3 and 1.01 cm2/(V·s, respectively. Crystals of SbTeI are characterized by XRD, SEM, and Raman analysis. Electrical activation energy is found to be 0.52 eV. It is suggested that this material may be studied for its application as a superconductor with Tc higher than room temperature.

Synthesis and thermoelectric performance of a p-type Bi0.4Sb1.6Te3 material developed via mechanical alloying

International Nuclear Information System (INIS)

Jimenez, Sandra; Perez, Jose G.; Tritt, Terry M.; Zhu, Song; Sosa-Sanchez, Jose L.; Martinez-Juarez, Javier; López, Osvaldo

2014-01-01

Highlights: • This paper shows a Bi 1.6 Sb 0.4 Te 3 alloy prepared by MA-SPS process. • A ZT value of about 1.2–1.3 around 360 K was achieved for this compound. • The lower sintering process was carried out in a short time. • The resulting material has a very fine microstructure and high density. - Abstract: A p-type Bi 0.4 Sb 1.6 Te 3 thermoelectric compound was fabricated via mechanical alloying of bismuth, antimony and tellurium elemental powders as starting materials. The mechanically alloyed compositions were sintered through a spark-plasma sintering (SPS) process. The effect of the milling time was investigated. In order to characterize the powders obtained via mechanical alloying, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analysis were used. The morphological evolution was studied by scanning electron microscopy (SEM). Results showed that the p-type Bi 0.4 Sb 1.6 Te 3 compound was formed after 2 h of milling. Further, the variation of milling time showed that the synthesized phase was stable. All the powders exhibit the same morphology albeit with slight differences. Measurements of the electrical resistivity, Seebeck coefficient and thermal conductivity were performed in the temperature range 300–520 K for the SPS samples. The resulting thermoelectric figure of merit ZT reaches a maximum of 1.2 at 360 K for the p-type bulk material with a 5 h milling time. This study demonstrates the possibility of preparing thermoelectric materials of high performance and short processing time

Microstructure and microwave dielectric properties of Na1/2Sm1/2TiO3 filled PTFE, an environmental friendly composites

Science.gov (United States)

Luo, Fuchuan; Tang, Bin; Yuan, Ying; Fang, Zixuan; Zhang, Shuren

2018-04-01

A study on Na1/2Sm1/2TiO3 filled and glassfiber reinforced polytetrafluoroethylene (PTFE) composites was described. The GF content was a fixed value of 4 wt%, and the NST content in the composite matrix changed from 26 to 66 wt%. The paper consisted of the manufactural process of the composite and the effects of filler content on the properties of the substrate, such as morphology, moisture absorption, density, dielectric properties and temperature coefficient of dielectric constant. As NST filler loading increased from 26 to 66 wt%, the dielectric constant and loss tangent experienced a continuously increase while the development in τε was opposite. X-Ray Diffraction, FTIR and XPS were used to analyze the microstructure of modified ceramic powder. It was proved that the silane coupling agent has been grafted on the NST surface successfully. At last, the NST/GF filled PTFE composites exhibited good dielectric constant (εr = 4.95), low dielectric loss (tan δ = 0.00147), acceptable water absorption (0.036) and temperature coefficient of dielectric constant (τε = -164) at filler loading of 4 wt% GF and 46 wt% NST.

Very smooth FeSb.sub.2./sub.Te and Ce.sub.0.1./sub.Fe.sub.0.7./sub.Co.sub.3.3./sub.Sb.sub.12./sub. layers prepared by modified PLD

Czech Academy of Sciences Publication Activity Database

Remsa, Jan; Jelínek, Miroslav; Kocourek, Tomáš; Zeipl, Radek; Navrátil, Jiří

2016-01-01

Roč. 45, č. 3 (2016), s. 1921-1926 ISSN 0361-5235 R&D Projects: GA ČR(CZ) GA13-33056S Institutional support: RVO:68378271 ; RVO:61389013 Keywords : PLD * RTA * thermoelectric layer * Harman * FeSb 2 Te * Ce 0.1 Fe 0.7 Co 3.3 Sb 12 Subject RIV: BM - Solid Matter Physics ; Magnetism; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 1.579, year: 2016

Formation, atomic structure, and electronic properties of GaSb quantum dots in GaAs

Energy Technology Data Exchange (ETDEWEB)

Timm, R.

2007-12-14

In this work, cross-sectional scanning tunneling microscopy and spectroscopy are used for the first time to study the shape, size, strain, chemical composition, and electronic properties of capped GaSb/GaAs QDs at the atomic scale. By evaluating such structural results on a variety of nanostructures built using different epitaxy methods and growth conditions, details on the underlying QD formation processes can be revealed. A cross-over from flat quantum wells (QWs) to optically active QDs can be observed in samples grown by metalorganic chemical vapor deposition (MOCVD) with increasing amount of GaSb, including self-assembled Sb accumulations within a still two-dimensional layer and tiny three-dimensional GaSb islands probably acting as precursor structures. The QWs consist of significantly intermixed material with stoichiometries of maximally 50% GaSb, additionally exhibiting small gaps filled with GaAs. A higher GaSb content up to nearly pure material is found in the QDs, being characterized by small sizes of up to 8 nm baselength and about 2 nm height. In spite of the intermixing, all nanostructures have rather abrupt interfaces, and no significant Sb segregation in growth direction is observed. This changes completely when molecular beam epitaxy (MBE) is used as growth method, in which case individual Sb atoms are found to be distributed over several nm above the nanostructures. Massive group-V atomic exchange processes are causing this strong inter-mixing and Sb segregation during GaAs overgrowth. In combination with the large strain inherent to GaSb/GaAs QDs, this segregation upon overgrowth is assumed to be the reason for a unique structural phenomenon: All MBE-grown QDs, independent of the amount of deposited GaSb, exhibit a ring structure, consisting of a ring body of high GaSb content and a more or less extended central gap filled with GaAs. These rings have formed in a self-assembled way even when the initial GaSb layer was overgrown considerably fast

Reconstructions of the sulfur-passivated InSb (100) surface

Energy Technology Data Exchange (ETDEWEB)

Ciochoń, Piotr, E-mail: piotr.ciochon@doctoral.uj.edu.pl; Olszowska, Natalia; Wróbel, Sonia; Kołodziej, Jacek

2017-04-01

Highlights: • Two new surface reconstructions of a S-passivated InSb (001) surface are reported. • The reconstructions are obtained through partial loss of surface sulfur. • They are characterized by the thickness of ∼4 Å and good crystallographic ordering. • The reconstructions provide adequate electronic passivation of the surface. - Abstract: We have studied the properties of the InSb (100) surface passivated with sulfur dimers emitted by the solid-state electrochemical cell in ultra-high vacuum. Annealing the passivated surface in the temperature equal to T = 326 °C led to the formation of the c(4 × 8) surface reconstruction, while increasing the temperature to T = 348 °C resulted in the transition to c(4 × 12) reconstruction. To the best of our knowledge these reconstructions have not been reported to date and are characterized by the exceptionally good crystallographic order. XPS studies revealed that there are at least 4 different chemical species of sulfur present on the surface and the estimated thickness of the sulfur layers is equal to around 4 Å. The surface reconstructions are characterized by the lowered intensity of the surface electronic states and resonances near the Fermi level, compared to the clean InSb surface, making them potentially very useful for the fabrication of InSb-based electronic and optoelectronic devices.

Exotic spin phases in the one-dimensional spin-1/2 quantum magnet LiCuSbO{sub 4} as seen by high-field NMR and ESR spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Iakovleva, Margarita [IFW Dresden, Dresden (Germany); TU Dresden, Dresden (Germany); Zavoisky Physical Technical Institute, Kazan (Russian Federation); Grafe, Hans-Joachim; Kataev, Vladislav; Alfonsov, Alexey; Sturza, Mihai I.; Wurmehl, Sabine [IFW Dresden, Dresden (Germany); Vavilova, Evgeniia [Zavoisky Physical Technical Institute, Kazan (Russian Federation); Nojiri, Hiroyuki [Institute of Materials Research, Sendai (Japan); Buechner, Bernd [IFW Dresden, Dresden (Germany); TU Dresden, Dresden (Germany)

2016-07-01

We will present our recent results of high-field NMR and sub-THz ESR studies of the quantum magnet LiCuSbO{sub 4} (LCSO) that presents an excellent model system of a one-dimensional spin-1/2 quantum magnet with frustrated exchange interactions. Such networks are predicted to exhibit a plethora of novel ground states beyond classical ferro- or antiferromagnetic phases. In LCSO the absence of a long-range magnetic order down to sub-Kelvin temperatures is suggestive of the realization of a quantum spin liquid state. Our NMR and ESR measurements in strong magnetic fields up to 16 Tesla reveal clear indications for the occurrence of an exotic field-induced hidden phase which we will discuss in terms of multipolar physics.

Development of sputtered CuSbS2 thin films grown by sequential deposition of binary sulfides

Science.gov (United States)

Medina-Montes, M. I.; Vieyra-Brito, O.; Mathews, N. R.; Mathew, X.

2018-05-01

In this work, CuSbS2 thin films were developed by annealing binary precursors deposited sequentially by rf magnetron sputtering. The recrystallization process was optimized and the films were extensively characterized using a number of tools such as XRD, Raman, SEM, energy dispersive x-ray spectroscopy, atomic force microscopy, Hall, UV–vis spectroscopy, Ellipsometry, Seebeck, and photoresponse. The influence of annealing temperature on the structure, morphology, elemental composition, optical and electrical properties are reported. Annealing below 350 °C resulted in famatinite (Cu3SbS4) and chalcostibite (CuSbS2) ternaries as well as binary phases. Phase-pure chalcostibite was obtained in the range of 350 °C–375 °C. At 400 °C, although CuSbS2 was predominant, tetrahedrite phase (Cu12Sb4S13) appeared as an additional phase. The elemental composition of the films was slightly sulfur deficient, and the atomic percentages of Cu, Sb and S showed a dependence on annealing temperature. The material properties of the phase-pure CuSbS2 thin films are: optical band gap in the range of 1.5–1.62 eV, absorption coefficient close to 105 cm‑1, atomic ratios of Cu/Sb ∼1 and (Cu + Sb)/S ∼1.2, crystal size 18.3–24.5 nm and grain size 50–300 nm. The films were photo-sensitive, showed p-type semiconductor behavior. Electrical resistivity, carrier density and hole mobility were 94–459 Ω cm, 1.6–7.0 × 1015 cm‑3 and 8.4–9.5 cm2 V‑1 s respectively.

Spin 1/2 Delafossite Honeycomb Compound Cu5SbO6

DEFF Research Database (Denmark)

Climent-Pascual, E.; Norby, Poul; Andersen, Niels Hessel

2012-01-01

Cu5SbO6 is found to have a monoclinic, Delafossite-derived structure consisting of alternating layers of O–Cu(I)–O sticks and magnetic layers of Jahn–Teller distorted Cu(II)O6 octahedra in an edge sharing honeycomb arrangement with Sb(V)O6 octahedra. This yields the structural formula Cu(I)3Cu(II...

Liquidus Projection and Isothermal Section of the Sb-Se-Sn System

Science.gov (United States)

Chang, Jui-shen; Chen, Sinn-wen

2017-12-01

Sb-Se-Sn ternary alloys are promising chalcogenide materials. The liquidus projection and 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system are determined. Numerous Sb-Se-Sn alloys are prepared, and their primary solidification phases are examined. In addition to the three terminal phases, (Sb), (Se) and (Sn), there are Sb2Sn3, SbSn, SnSe, SnSe2, Sb2Se3, Sn2Sb9Se9, and SnSb2Se4 phases. In addition, there are two miscibility gaps along the Sb-Se and Se-Sn and sides. There are ten invariant reactions in the Sb-Se-Sn ternary system, and seven of them are experimentally determined in this study. The lowest reaction temperature of determined invariant reaction is L + SbSn = (Sn) + SnSe at 515.4 K ± 5 K (242.2 °C ± 5 °C). There are nine tie-triangles, which are Liquid + SbSn + SnSe, SbSn + SnSe + (Sb), SnSe + (Sb) + Sn2Sb9Se9, (Sb) + Sb2Se3 + Sn2Sb9Se9, SnSe + Sn2Sb9Se9 + SnSb2Se4, Sb2Se3 + Sn2Sb9Se9 + SnSb2Se4, SnSe + SnSe2 + SnSb2Se4, SnSe2 + SnSb2Se4 + Sb2Se3, and SnSe2 + Sb2Se3 + Liquid in the 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system.

Increasing Polymer Solar Cell Fill Factor by Trap-Filling with F4-TCNQ at Parts Per Thousand Concentration.

Science.gov (United States)

Yan, Han; Manion, Joseph G; Yuan, Mingjian; García de Arquer, F Pelayo; McKeown, George R; Beaupré, Serge; Leclerc, Mario; Sargent, Edward H; Seferos, Dwight S

2016-08-01

Intrinsic traps in organic semiconductors can be eliminated by trap-filling with F4-TCNQ. Photovoltaic tests show that devices with F4-TCNQ at parts per thousand concentration outperform control devices due to an improved fill factor. Further studies confirm the trap-filling pathway and demonstrate the general nature of this finding. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposition and electrochemical characterisation of thick and thin coatings of Sb and Sb/Sb2O3 particles for Li-ion battery anodes

International Nuclear Information System (INIS)

Bryngelsson, Hanna; Eskhult, Jonas; Edstroem, Kristina; Nyholm, Leif

2007-01-01

The possibilities to electrodeposit thick coatings composed of nanoparticles of Sb and Sb 2 O 3 for use as high-capacity anode materials in Li-ion batteries have been investigated. It is demonstrated that the stability of the coatings depends on their Sb 2 O 3 concentrations as well as microstructure. The electrodeposition reactions in electrolytes with different pH and buffer capacities were studied using chronopotentiometry and electrochemical quartz crystal microbalance measurements. The obtained deposits, which were characterised with XRD and SEM, were also tested as anode materials in Li-ion batteries. The influence of the pH and buffer capacity of the deposition solution on the composition and particle size of the deposits were studied and it is concluded that depositions from a poorly buffered solution of antimony-tartrate give rise to good anode materials due to the inclusion of precipitated Sb 2 O 3 nanoparticles in the Sb coatings. Depositions under conditions yielding pure Sb coatings give rise to deposits composed of large crystalline particles with poor anode stabilities. The presence of a plateau at about 0.8 V versus Li + /Li due to SEI forming reactions and the origin of another plateau at about 0.4 V versus Li + /Li seen during the lithiation of thin Sb coatings are also discussed. It is demonstrated that the 0.4 V plateau is present for Sb coatings for which the (0 1 2) peak is the main peak in the XRD diffractogram

Enhanced thermoelectric performance with participation of F-electrons in β-Zn{sub 4}Sb{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu, Mian; Qin, Xiaoying, E-mail: xyqin@issp.ac.cn; Liu, Changsong; Li, Xiyu; Yang, Xiuhui

2014-01-25

Highlights: • Find an effective route to enhance the thermoelectric figure of merit of β-Zn{sub 4}Sb{sub 3}. • Provide the corresponding theoretical predictions. • Investigated the effects of doping Ce and Pr in β-Zn{sub 4}Sb{sub 3}. -- Abstract: The effects of rare-earth element impurities Ce and Pr on the electronic structure and thermoelectric properties of β-Zn{sub 4}Sb{sub 3} were investigated by performing self-consistent ab initio electronic structure calculations within density functional theory and solving the Boltzmann transport equations within the relaxation time approximation. The results demonstrated that these rare-earth element impurities with f orbitals could introduce giant sharp resonant peaks in the density of states (DOS) near the host valence band maximum in energy. And these deliberately engineered DOS peaks result in a sharp increase of the room-temperature Seebeck coefficient and power factor from those of impurity-free system by a factor of 100 and 22, respectively. Additionally, with the simultaneous declining of carrier thermal conductivity, a potential 5-fold increase at least with Ce doping and more than 3 times increase with Pr doping in the thermoelectric figure of merit of β-Zn{sub 4}Sb{sub 3} at room temperature are achieved. The effective DOS restructuring strategy opens up new opportunities for thermoelectric power generation and waste heat recovery at large scale.

Finite-size calculations of FQHE states at filling ν = 1/2

International Nuclear Information System (INIS)

Fano, G.

1987-01-01

The results of numerical calculations, performed in the spherical geometry, of FQHE states of N ≤ 12 electrons on the lowest Landau level at filling ν = 1/2, are presented. The extrapolated value for the energy per particle is -0.469±0.005, in the usual units e 2 /a 0 . Densities and pair correlation functions of the ground states are computed. The pair correlation are 'Wigner-crystal-like', with maxima corresponding to regular polyhedra. For N=4, 8 and 10 it is found that the system presents a broken rotational invariance which generalizes the broken particle-hole symmetry already known in different gauges. Quasi-particles, quasi-holes and the 'exciton' spectrum are computed, and some microscopic wave functions are examined. The quasi-particles and the quasi-holes are not localized; this suggests a possible 'deformability' of the system

Physics of bandgap formation in Cu-Sb-Se based novel thermoelectrics: the role of Sb valency and Cu d levels.

Science.gov (United States)

Do, Dat; Ozolins, Vidvuds; Mahanti, S D; Lee, Mal-Soon; Zhang, Yongsheng; Wolverton, C

2012-10-17

In this paper we discuss the results of ab initio electronic structure calculations for Cu(3)SbSe(4) (Se4) and Cu(3)SbSe(3) (Se3), two narrow bandgap semiconductors of thermoelectric interest. We find that Sb is trivalent in both the compounds, in contrast to a simple nominal valence (ionic) picture which suggests that Sb should be 5 + in Se4. The gap formation in Se4 is quite subtle, with hybridization between Sb 5s and the neighboring Se 4s, 4p orbitals, position of Cu d states, and non-local exchange interaction, each playing significant roles. Thermopower calculations show that Se4 is a better p-type system. Our theoretical results for Se4 agree very well with recent experimental results obtained by Skoug et al (2011 Sci. Adv. Mater. 3 602).

Chemical Substitution-Induced and Competitive Formation of 6H and 3C Perovskite Structures in Ba3-xSrxZnSb2O9: The Coexistence of Two Perovskites in 0.3 ≤ x ≤ 1.0.

Science.gov (United States)

Li, Jing; Jiang, Pengfei; Gao, Wenliang; Cong, Rihong; Yang, Tao

2017-11-20

6H and 3C perovskites are important prototype structures in materials science. We systemically studied the structural evolution induced by the Sr 2+ -to-Ba 2+ substitution to the parent 6H perovskite Ba 3 ZnSb 2 O 9 . The 6H perovskite is only stable in the narrow range of x ≤ 0.2, which attributes to the impressibility of [Sb 2 O 9 ]. The preference of 90° Sb-O-Sb connection and the strong Sb 5+ -Sb 5+ electrostatic repulsion in [Sb 2 O 9 ] are competitive factors to stabilize or destabilize the 6H structure when chemical pressure was introduced by Sr 2+ incorporation. Therefore, in the following, a wide two-phase region containing 1:2 ordered 6H-Ba 2.8 Sr 0.2 ZnSb 2 O 9 and rock-salt ordered 3C-Ba 2 SrZnSb 2 O 9 was observed (0.3 ≤ x ≤ 1.0). In the final, the successive symmetry descending was established from cubic (Fm3̅m, 1.3 ≤ x ≤ 1.8) to tetragonal (I4/m, 2.0 ≤ x ≤ 2.4), and finally to monoclinic (I2/m, 2.6 ≤ x ≤ 3.0). Here we proved that the electronic configurations of B-site cations, with either empty, partially, or fully filled d-shell, would also affect the structure stabilization, through the orientation preference of the B-O covalent bonding. Our investigation gives a deeper understanding of the factors to the competitive formation of perovskite structures, facilitating the fine manipulation on their physical properties.

Nonpeptidic urotensin-II receptor antagonists I: in vitro pharmacological characterization of SB-706375

Science.gov (United States)

Douglas, Stephen A; Behm, David J; Aiyar, Nambi V; Naselsky, Diane; Disa, Jyoti; Brooks, David P; Ohlstein, Eliot H; Gleason, John G; Sarau, Henry M; Foley, James J; Buckley, Peter T; Schmidt, Dulcie B; Wixted, William E; Widdowson, Katherine; Riley, Graham; Jin, Jian; Gallagher, Timothy F; Schmidt, Stanley J; Ridgers, Lance; Christmann, Lisa T; Keenan, Richard M; Knight, Steven D; Dhanak, Dashyant

2005-01-01

SB-706375 potently inhibited [125I]hU-II binding to both mammalian recombinant and ‘native' UT receptors (Ki 4.7±1.5 to 20.7±3.6 nM at rodent, feline and primate recombinant UT receptors and Ki 5.4±0.4 nM at the endogenous UT receptor in SJRH30 cells). Prior exposure to SB-706375 (1 μM, 30 min) did not alter [125I]hU-II binding affinity or density in recombinant cells (KD 3.1±0.4 vs 5.8±0.9 nM and Bmax 3.1±1.0 vs 2.8±0.8 pmol mg−1) consistent with a reversible mode of action. The novel, nonpeptidic radioligand [3H]SB-657510, a close analogue of SB-706375, bound to the monkey UT receptor (KD 2.6±0.4 nM, Bmax 0.86±0.12 pmol mg−1) in a manner that was inhibited by both U-II isopeptides and SB-706375 (Ki 4.6±1.4 to 17.6±5.4 nM) consistent with the sulphonamides and native U-II ligands sharing a common UT receptor binding domain. SB-706375 was a potent, competitive hU-II antagonist across species with pKb 7.29–8.00 in HEK293-UT receptor cells (inhibition of [Ca2+]i-mobilization) and pKb 7.47 in rat isolated aorta (inhibition of contraction). SB-706375 also reversed tone established in the rat aorta by prior exposure to hU-II (Kapp∼20 nM). SB-706375 was a selective U-II antagonist with ⩾100-fold selectivity for the human UT receptor compared to 86 distinct receptors, ion channels, enzymes, transporters and nuclear hormones (Ki/IC50>1 μM). Accordingly, the contractile responses induced in isolated aortae by KCl, phenylephrine, angiotensin II and endothelin-1 were unaltered by SB-706375 (1 μM). In summary, SB-706375 is a high-affinity, surmountable, reversible and selective nonpeptide UT receptor antagonist with cross-species activity that will assist in delineating the pathophysiological actions of U-II in mammals. PMID:15852036

Brain imaging of serotonin 4 receptors in humans with [11C]SB207145-PET

DEFF Research Database (Denmark)

Marner, Lisbeth; Gillings, Nic; Madsen, Karine

2010-01-01

Pharmacological stimulation of the serotonin 4 (5-HT(4)) receptor has shown promise for treatment of Alzheimer's disease and major depression. A new selective radioligand, [(11)C]SB207145, for positron emission tomography (PET) was used to quantify brain 5-HT(4) receptors in sixteen healthy......(max) was in accordance with post-mortem brain studies (Spearman's r=0.83, p=0.04), and the regional binding potentials, BP(ND), were on average 2.6 in striatum, 0.42 in prefrontal cortex, and 0.91 in hippocampus. We found no effect of sex but a decreased binding with age (p=0.046). A power analysis showed that, given......-HT(4) receptor binding in human brain can be reliably assessed with [(11)C]SB207145, which is encouraging for future PET studies of drug occupancy or patients with neuropsychiatric disorders....

Sb-related defects in Sb-doped ZnO thin film grown by pulsed laser deposition

Science.gov (United States)

Luo, Caiqin; Ho, Lok-Ping; Azad, Fahad; Anwand, Wolfgang; Butterling, Maik; Wagner, Andreas; Kuznetsov, Andrej; Zhu, Hai; Su, Shichen; Ling, Francis Chi-Chung

2018-04-01

Sb-doped ZnO films were fabricated on c-plane sapphire using the pulsed laser deposition method and characterized by Hall effect measurement, X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and positron annihilation spectroscopy. Systematic studies on the growth conditions with different Sb composition, oxygen pressure, and post-growth annealing were conducted. If the Sb doping concentration is lower than the threshold ˜8 × 1020 cm-3, the as-grown films grown with an appropriate oxygen pressure could be n˜4 × 1020 cm-3. The shallow donor was attributed to the SbZn related defect. Annealing these samples led to the formation of the SbZn-2VZn shallow acceptor which subsequently compensated for the free carrier. For samples with Sb concentration exceeding the threshold, the yielded as-grown samples were highly resistive. X-ray diffraction results showed that the Sb dopant occupied the O site rather than the Zn site as the Sb doping exceeded the threshold, whereas the SbO related deep acceptor was responsible for the high resistivity of the samples.

Characterization and complete genome sequence of a novel N4-like bacteriophage, pSb-1 infecting Shigella boydii.

Science.gov (United States)

Jun, Jin Woo; Yun, Sae Kil; Kim, Hyoun Joong; Chai, Ji Young; Park, Se Chang

2014-10-01

Shigellosis is one of major foodborne pathogens in both developed and developing countries. Although antibiotic therapy is considered an effective treatment for shigellosis, the imprudent use of antibiotics has led to the increase of multiple-antibiotic-resistant Shigella species globally. In this study, we isolated a virulent Podoviridae bacteriophage (phage), pSb-1, that infects Shigella boydii. One-step growth analysis revealed that this phage has a short latent period (15 min) and a large burst size (152.63 PFU/cell), indicating that pSb-1 has good host infectivity and effective lytic activity. The double-stranded DNA genome of pSb-1 is composed of 71,629 bp with a G + C content of 42.74%. The genome encodes 103 putative ORFs, 9 putative promoters, 21 transcriptional terminators, and one tRNA region. Genome sequence analysis of pSb-1 and comparative analysis with the homologous phage EC1-UPM, N4-like phage revealed that there is a high degree of similarity (94%, nucleotide sequence identity) between pSb-1 and EC1-UPM in 73 of the 103 ORFs of pSb-1. The results of this investigation indicate that pSb-1 is a novel virulent N4-like phage infecting S. boydii and that this phage might have potential uses against shigellosis. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Sb(V reactivity with human blood components: redox effects.

Directory of Open Access Journals (Sweden)

Silvana López

Full Text Available We assessed the reactivity of Sb(V in human blood. Sb(V reactivity was determined using an HPLC-HG-AFS hyphenated system. Sb(V was partially reduced to Sb(III in blood incubation experiments; however, Sb(III was a highly unstable species. The addition of 0.1 mol L(-1 EDTA prevented Sb(III oxidation, thus enabling the detection of the reduction of Sb(V to Sb(III. The transformation of Sb(V to Sb(III in human whole blood was assessed because the reduction of Sb(V in human blood may likely generate redox side effects. Our results indicate that glutathione was the reducing agent in this reaction and that Sb(V significantly decreased the GSH/GSSG ratio from 0.32 ± 0.09 to 0.07 ± 0.03. Moreover, the presence of 200 ng mL(-1 of Sb(V increased the activity of superoxide dismutase from 4.4 ± 0.1 to 7.0 ± 0.4 U mL(-1 and decreased the activity of glutathione peroxidase from 62 ± 1 to 34 ± 2 nmol min(-1 mL(-1.

Comparison of the electrochemical performance of mesoscopic Cu2Sb, SnSb and Sn/SnSb alloy powders

International Nuclear Information System (INIS)

Zhang Ge; Huang Kelong; Liu Suqin; Zhang Wei; Gong Benli

2006-01-01

Cu 2 Sb, SnSb and Sn/SnSb mesoscopic alloy powders were prepared by chemical reduction, respectively. The crystal structures and particle morphology of Cu 2 Sb, SnSb and Sn/SnSb were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The electrochemical performances of the Cu 2 Sb, SnSb and Sn/SnSb electrodes were investigated by galvanostatic charge and discharge cycling and electrochemical impedance spectroscopy (EIS). The results showed the first charge and discharge capacities of SnSb and Sn/SnSb were higher than Cu 2 Sb, but after 15 cycles, the charge capacity fading rates of Cu 2 Sb, Sn/SnSb and Sn/SnSb were 26.16%, 55.33% and 47.39%, respectively. Cu 2 Sb had a better cycle performance, and Sn/SnSb multiphase alloy was prior to pure SnSb due to the existence of excessive Sn in Sn/SnSb system

Sequential and simultaneous adsorption of Sb(III) and Sb(V) on ferrihydrite: Implications for oxidation and competition.

Science.gov (United States)

Qi, Pengfei; Pichler, Thomas

2016-02-01

Antimony (Sb) is a naturally occurring element of growing environmental concern whose toxicity, adsorption behavior and other chemical properties are similar to that of arsenic (As). However, less is known about Sb compared to As. Individual and simultaneous adsorption experiments with Sb(III) and Sb(V) were conducted in batch mode with focus on the Sb speciation of the remaining liquid phase during individual Sb(III) adsorption experiments. The simultaneous adsorption and oxidation of Sb(III) was confirmed by the appearance of Sb(V) in the solution at varying Fe/Sb ratios (500, 100 and 8) and varying pH values (3.8, 7 and 9). This newly formed Sb(V) was subsequently removed from solution at a Fe/Sb ratio of 500 or at a pH of 3.8. However, more or less only Sb(V) was observed in the liquid phase at the end of the experiments at lower Fe/Sb ratios and higher pH, indicating that competition took place between the newly formed Sb(V) and Sb(III), and that Sb(III) outcompeted Sb(V). This was independently confirmed by simultaneous adsorption experiments of Sb(III) and Sb(V) in binary systems. Under such conditions, the presence of Sb(V) had no influence on the adsorption of Sb(III) while Sb(V) adsorption was significantly inhibited by Sb(III) over a wide pH range (4-10). Thus, in the presence of ferrihydrite and under redox conditions, which allow the presence of both Sb species, Sb(V) should be the dominant species in aquatic environments, since Sb(III) is adsorbed preferentially and at the same time oxidized to Sb(V). Copyright © 2015 Elsevier Ltd. All rights reserved.

Complexation of HSA with different forms of antimony (Sb): An application of fluorescence spectroscopy

International Nuclear Information System (INIS)

Song, Wenjuan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong

2013-01-01

Antimony (Sb) pollution has been of a great environmental concern in some areas in China. Sb enters human body via drinking water, inhalation and food chain, unavoidably interacts with human serum albumin (HSA) in blood plasma, and consequently does harm to human health. The harmful effects of Sb on human health depend on the Sb species and their binding ability to HSA. In the present study, binding of three forms of Sb with HSA was investigated by excitation-emission matrix (EEM) spectroscopy. All of antimony potassium tartrate, antimony trichloride and potassium pyroantimonate quenched fluorescence of HSA. Values of conditional stability constant K a (×10 5 /M) for Sb and HSA systems were 8.13–9.12 for antimony potassium tartrate, 2.51–4.27 for antimony trichloride and 3.63–9.77 for potassium pyroantimonate. The binding constant K b (×10 4 /M) values of HSA with antimony potassium tartrate, antimony trichloride and potassium pyroantimonate were 0.02–0.07, 3.55–5.01, and 0.07–1.08, respectively. There was one independent class of binding site for antimony trichloride towards HSA. There was more than one Sb binding site and negative cooperativity between multiple binding sites for potassium pyroantimonate and antimony potassium tartrate towards HSA. The binding ability of HSA to complex Sb followed the order: antimony trichloride>potassium pyroantimonate>antimony potassium tartrate. -- Highlights: ► The first study reporting interaction of Sb with HSA. ► Sb can effectively quench the fluorescence of HSA. ► The binding ability of HSA to Sb was dependent on the form of Sb. ► Binding differences indicate differences in toxicity of various forms Sb to human. ► HAS-Sb binding parameters are important for understanding toxicity of Sb

Complexation of HSA with different forms of antimony (Sb): An application of fluorescence spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Song, Wenjuan [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Zhang, Daoyong [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Pan, Xiangliang, E-mail: xlpan@ms.xjb.ac.cn [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Lee, Duu-Jong [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China)

2013-04-15

Antimony (Sb) pollution has been of a great environmental concern in some areas in China. Sb enters human body via drinking water, inhalation and food chain, unavoidably interacts with human serum albumin (HSA) in blood plasma, and consequently does harm to human health. The harmful effects of Sb on human health depend on the Sb species and their binding ability to HSA. In the present study, binding of three forms of Sb with HSA was investigated by excitation-emission matrix (EEM) spectroscopy. All of antimony potassium tartrate, antimony trichloride and potassium pyroantimonate quenched fluorescence of HSA. Values of conditional stability constant K{sub a} (×10{sup 5}/M) for Sb and HSA systems were 8.13–9.12 for antimony potassium tartrate, 2.51–4.27 for antimony trichloride and 3.63–9.77 for potassium pyroantimonate. The binding constant K{sub b} (×10{sup 4}/M) values of HSA with antimony potassium tartrate, antimony trichloride and potassium pyroantimonate were 0.02–0.07, 3.55–5.01, and 0.07–1.08, respectively. There was one independent class of binding site for antimony trichloride towards HSA. There was more than one Sb binding site and negative cooperativity between multiple binding sites for potassium pyroantimonate and antimony potassium tartrate towards HSA. The binding ability of HSA to complex Sb followed the order: antimony trichloride>potassium pyroantimonate>antimony potassium tartrate. -- Highlights: ► The first study reporting interaction of Sb with HSA. ► Sb can effectively quench the fluorescence of HSA. ► The binding ability of HSA to Sb was dependent on the form of Sb. ► Binding differences indicate differences in toxicity of various forms Sb to human. ► HAS-Sb binding parameters are important for understanding toxicity of Sb.

Crystallization and memory programming characteristics of Ge-doped SbTe materials of varying Sb : Te ratio

International Nuclear Information System (INIS)

Jeong, Jeung-hyun; Lee, Hyun Seok; Lee, Suyoun; Lee, Taek Sung; Kim, Won Mok; Wu Zhe; Cheong, Byung-ki; Kim, Seul Cham; Oh, Kyu Hwan

2009-01-01

A phase change memory (PCM) utilizes resistivity changes accompanying fast transitions from an amorphous to a crystalline phase (SET) and vice versa (RESET). An investigation was made on the SET characteristics of PCM cells with Ge-doped SbTe (Ge-ST) materials of two different Sb : Te ratios (4.53 and 2.08). For the material of higher Sb : Te (4.53), a SET operation was completed within several tens of nanoseconds via nucleation-free crystallization whereas the material of lower Sb : Te (2.08) rendered a slower SET operation requiring several hundred nanoseconds for a nucleation-mediated crystallization. From measurements of nucleation and growth kinetics via laser-induced crystallization, the observed SET characteristics of the former case were found to derive from a growth time about 10 3 times shorter than the nucleation time and those of the latter from a much shorter nucleation time as well as a longer growth time than in the former case. The measured nucleation kinetics of the lower Sb : Te (2.08) material is unexpected from the existing data, which has led us to advance an interesting finding that there occurs a trend-reversing change in the nucleation kinetics of the Ge-ST materials around the eutectic composition (Sb : Te ∼2.6); nucleation is accelerated with the increase in the Sb : Te ratio above Sb : Te of 2.6, but with a decrease in the Sb : Te ratio below it.

Hole-dominated transport in InSb nanowires grown on high-quality InSb films

Energy Technology Data Exchange (ETDEWEB)

Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U., E-mail: usha.philipose@unt.edu [University of North Texas, Department of Physics (United States)

2016-12-15

We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between Sb{sub 2}S{sub 3} and In and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40–60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 10{sup 17} cm{sup −3} and 1000 cm{sup 2} V{sup −1} s{sup −1}, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

Gel-combustion synthesis of CoSb2O6 and its reduction to powdery Sb2Co alloy

Directory of Open Access Journals (Sweden)

MAJA JOVIC

2009-01-01

Full Text Available Sb2Co alloy in powdery form was synthesized via reduction with gaseous hydrogen of the oxide CoSb2O6, obtained by the citrate gel-combustion technique. The precursor was an aqueous solution of antimony nitrate, cobalt nitrate and citric acid. The precursor solution with mole ratio Co(II/Sb(V of 1:2 was gelatinized by evaporation of water. The gel was heated in air up to the temperature of self-ignition. The product of gel combustion was a mixture of oxides and it had to be additionally thermally treated in order to be converted to pure CoSb2O6. The reduction of CoSb2O6 by gaseous hydrogen yielded powdery Sb2Co as the sole phase. The process of oxide reduction to alloy was controlled by thermogravimetry, while X-ray diffractometry was used to control the phase compositions of both the oxides and alloys.

Hole-dominated transport in InSb nanowires grown on high-quality InSb films

Science.gov (United States)

Algarni, Zaina; George, David; Singh, Abhay; Lin, Yuankun; Philipose, U.

2016-12-01

We have developed an effective strategy for synthesizing p-type indium antimonide (InSb) nanowires on a thin film of InSb grown on glass substrate. The InSb films were grown by a chemical reaction between S b 2 S 3 and I n and were characterized by structural, compositional, and optical studies. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that the surface of the substrate is covered with a polycrystalline InSb film comprised of sub-micron sized InSb islands. Energy dispersive X-ray (EDX) results show that the film is stoichiometric InSb. The optical constants of the InSb film, characterized using a variable-angle spectroscopic ellipsometer (VASE) shows a maximum value for refractive index at 3.7 near 1.8 eV, and the extinction coefficient (k) shows a maximum value 3.3 near 4.1 eV. InSb nanowires were subsequently grown on the InSb film with 20 nm sized Au nanoparticles functioning as the metal catalyst initiating nanowire growth. The InSb nanowires with diameters in the range of 40-60 nm exhibit good crystallinity and were found to be rich in Sb. High concentrations of anions in binary semiconductors are known to introduce acceptor levels within the band gap. This un-intentional doping of the InSb nanowire resulting in hole-dominated transport in the nanowires is demonstrated by the fabrication of a p-channel nanowire field effect transistor. The hole concentration and field effect mobility are estimated to be ≈1.3 × 1017 cm-3 and 1000 cm2 V-1 s-1, respectively, at room temperature, values that are particularly attractive for the technological implications of utilizing p-InSb nanowires in CMOS electronics.

Determination of the enthalpy of fusion and thermal diffusivity for ternary Cu_6_0_−_xSn_xSb_4_0 alloys

International Nuclear Information System (INIS)

Zhai, W.; Zhou, K.; Hu, L.; Wei, B.

2016-01-01

Highlights: • The increasing Sn content reduces the liquidus temperature. • High Sn content results in lower enthalpy of fusion by polynomial functions. • The thermal diffusivity drops from the solid toward the semi-solid state. • Undercoolability of alloys with primary Cu_2Sb phase is stronger than others. - Abstract: The liquidus and solidus temperatures, enthalpy of fusion, and the temperature dependence of thermal diffusivity for ternary Cu_6_0_−_xSn_xSb_4_0 alloys were systematically measured by DSC and laser flash methods. It is found that both the liquidus temperature and the enthalpy of fusion decrease with the rise of Sn content, and their relationships with alloy composition were established by polynomial functions. The thermal diffusivity usually drops from the solid toward the semi-solid state. The undercoolability of those liquid Cu_6_0_−_xSn_xSb_4_0 alloys with primary Cu_2Sb solid phase is stronger than the others with primary β(SnSb) intermetallic compound, and the increase of cooling rate facilitates further undercooling. Microstructural observation indicates that both of the primary Cu_2Sb and β(SnSb) intermetallic compounds in ternary Cu_6_0_−_xSn_xSb_4_0 alloys grow in faceted mode, and develop into coarse flakes and polygonal blocks.

Lower lattice thermal conductivity in SbAs than As or Sb monolayers: a first-principles study.

Science.gov (United States)

Guo, San-Dong; Liu, Jiang-Tao

2017-12-06

Phonon transport in group-VA element (As, Sb and Bi) monolayer semiconductors has been widely investigated in theory, and, of them, monolayer Sb (antimonene) has recently been synthesized. In this work, phonon transport in monolayer SbAs is investigated with a combination of first-principles calculations and the linearized phonon Boltzmann equation. It is found that the lattice thermal conductivity of monolayer SbAs is lower than those of both monolayer As and Sb, and the corresponding sheet thermal conductance is 28.8 W K -1 at room temperature. To understand the lower lattice thermal conductivity in monolayer SbAs than those in monolayer As and Sb, the group velocities and phonon lifetimes of monolayer As, SbAs and Sb are calculated. The calculated results show that the group velocities of monolayer SbAs are between those of monolayer As and Sb, but that the phonon lifetimes of SbAs are smaller than those of both monolayer As and Sb. Hence, the low lattice thermal conductivity in monolayer SbAs is attributed to very small phonon lifetimes. Unexpectedly, the ZA branch has very little contribution to the total thermal conductivity, only 2.4%, which is obviously different from those of monolayer As and Sb with very large contributions. This can be explained by very small phonon lifetimes for the ZA branch of monolayer SbAs. The lower lattice thermal conductivity of monolayer SbAs compared to that of monolayer As or Sb can be understood by the alloying of As (Sb) with Sb (As), which should introduce phonon point defect scattering. We also consider the isotope and size effects on the lattice thermal conductivity. It is found that isotope scattering produces a neglectful effect, and the lattice thermal conductivity with a characteristic length smaller than 30 nm can reach a decrease of about 47%. These results may offer perspectives on tuning the lattice thermal conductivity by the mixture of multiple elements for applications of thermal management and

Characteristics of phase transition and separation in a In-Ge-Sb-Te system

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Jin [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Jang, Moon Hyung [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States); Park, Seung-Jong [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Cho, Mann-Ho, E-mail: mh.cho@yonsei.ac.kr [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Ko, Dae-Hong [Department of Material Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

2012-10-01

Highlights: Black-Right-Pointing-Pointer InGeSbTe films were fabricated via co-deposition stoichiometric GST and IST targets. Black-Right-Pointing-Pointer As the amount of IST was increased in InGeSbTe, the value for V{sub th} and the phase transition temperature were increased. Black-Right-Pointing-Pointer The phase separation in InGeSbTe is caused by differences in the enthalpy change for formation and different atomic concentrations. - Abstract: In-doped GeSbTe films were deposited by ion beam sputtering deposition (IBSD) using Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) and In{sub 3}Sb{sub 1}Te{sub 2} (IST) as targets. The phase change characteristics of the resulting films were then investigated by electrical measurements, including static testing, in situ 4-point R{sub s} measurements, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The threshold voltage of the films increased, with increasing levels of IST. This phenomenon is consistent with the increased crystallization temperature in X-ray data and in situ 4-point R{sub s} data. In addition, in In{sub 28}Ge{sub 12}Sb{sub 26}Te{sub 34}, multiple V{sub th} values with a stepwise change are observed. The minimum time for the crystallization of InGeSbTe films was shorter than that for GST. X-ray data and Raman data for the crystalline structure show that phase separation to In{sub 2}Te{sub 3} occurred in all of the InGeSbTe samples after annealing at 350 Degree-Sign C. Moreover, in the case of InGeSbTe films with high concentrations of In (28 at.%), Sb phase separation was also observed. The observed phases indicate that the origin of the phase separation of InGeSbTe films is from the enthalpy change of formation and differences in Ge-Te, In-Te, Sb-Te, In-Sb and In-In bond energies.

Electronic and magnetic properties of SmCrSb3 and GdCrSb3: A first principles study

International Nuclear Information System (INIS)

Sandeep; Ghimire, M.P.; Thapa, R.K.

2011-01-01

The density of states (DOS) and the magnetic moments of SmCrSb 3 and GdCrSb 3 have been studied by first principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). For the exchange-correlation potential, the local-spin density approximations with correlation energy (LSDA+U) method have been used. Total and partial DOS have been computed using the WIEN2k code. DOS result shows the exchange-splittings of Cr-3d and rare-earth (R) 4f states electrons, which are responsible for the ground state ferromagnetic (FM) behavior of the systems. The FM behavior of these systems is strongly influenced by the average number of Cr-3d and Sm (Gd) 4f-electrons. The effective moment of SmCrSb 3 is found to be 7.07 μ B while for GdCrSb 3 it is 8.27 μ B . The Cr atom plays a significant role on the magnetic properties due to the hybridization between Cr-3d and Sb-5p states. - Highlights: → DOS and the magnetic moments of SmCrSb 3 and GdCrSb 3 are studied by full-FP-LAPW method. → Exchange splitting of eg and t2g of Cr-3d states and the rare-earth 4f state electrons are responsible for ground state ferromagnetism. → Rare-earth magnetic moments are greater than Cr moment indicating presence of 4f states.

Enhanced Charge Extraction of Li-Doped TiO2 for Efficient Thermal-Evaporated Sb2S3 Thin Film Solar Cells

Science.gov (United States)

Lan, Chunfeng; Luo, Jingting; Lan, Huabin; Fan, Bo; Peng, Huanxin; Zhao, Jun; Sun, Huibin; Zheng, Zhuanghao; Liang, Guangxing; Fan, Ping

2018-01-01

We provided a new method to improve the efficiency of Sb2S3 thin film solar cells. The TiO2 electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb2S3 solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO2 films. Compared with the undoped TiO2, Li-doped mesoporous TiO2 dramatically improved the photo-voltaic performance of the thermal-evaporated Sb2S3 thin film solar cells, with the average power conversion efficiency (PCE) increasing from 1.79% to 4.03%, as well as the improved open-voltage (Voc), short-circuit current (Jsc) and fill factors. The best device based on Li-doped TiO2 achieved a power conversion efficiency up to 4.42% as well as a Voc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb2S3 solar cells. This study showed that Li-doping on TiO2 can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb2S3-based solar cells. PMID:29495612

Enhanced Charge Extraction of Li-Doped TiO2 for Efficient Thermal-Evaporated Sb2S3 Thin Film Solar Cells

Directory of Open Access Journals (Sweden)

Chunfeng Lan

2018-02-01

Full Text Available We provided a new method to improve the efficiency of Sb2S3 thin film solar cells. The TiO2 electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb2S3 solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO2 films. Compared with the undoped TiO2, Li-doped mesoporous TiO2 dramatically improved the photo-voltaic performance of the thermal-evaporated Sb2S3 thin film solar cells, with the average power conversion efficiency (PCE increasing from 1.79% to 4.03%, as well as the improved open-voltage (Voc, short-circuit current (Jsc and fill factors. The best device based on Li-doped TiO2 achieved a power conversion efficiency up to 4.42% as well as a Voc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb2S3 solar cells. This study showed that Li-doping on TiO2 can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb2S3-based solar cells.

Room-temperature broadband InAsSb flip-chip photodiodes with λcutoff = 4.5 μm

International Nuclear Information System (INIS)

Zakhgeim, A. L.; Zotova, N. V.; Il'inskaya, N. D.; Karandashev, S. A.; Matveev, B. A.; Remennyi, M. A.; Stus', N. M.; Chernyakov, A. E.

2009-01-01

Equilibrium and nonequilibrium IR images of p-InAsSbP/n-InAsSb/n + -InAs photodiodes including the images obtained in the electroluminescence and negative luminescence modes have been analyzed. The contact reflectivity has been evaluated. The influence of the substrate's doping level and mesa depth on the quantum efficiency and sensitivity of a backside illuminated photodiode sensitive in the 2.7-4.5 μm range is discussed.

Ternary CaCu{sub 4}P{sub 2}-type pnictides AAg{sub 4}Pn{sub 2} (A=Sr, Eu; Pn=As, Sb)

Energy Technology Data Exchange (ETDEWEB)

Stoyko, Stanislav S.; Khatun, Mansura; Scott Mullen, C. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Mar, Arthur, E-mail: arthur.mar@ualberta.ca [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada)

2012-08-15

Four ternary pnictides AAg{sub 4}Pn{sub 2} (A=Sr, Eu; Pn=As, Sb) were prepared by reactions of the elements at 850 Degree-Sign C and their crystal structures were determined from single-crystal X-ray diffraction studies. These silver-containing pnictides AAg{sub 4}Pn{sub 2} adopt the trigonal CaCu{sub 4}P{sub 2}-type structure (Pearson symbol hR21, space group R3-bar m, Z=3; a=4.5555(6) A, c=24.041(3) A for SrAg{sub 4}As{sub 2}; a=4.5352(2) A, c=23.7221(11) A for EuAg{sub 4}As{sub 2}; a=4.7404(4) A, c=25.029(2) A for SrAg{sub 4}Sb{sub 2}; a=4.7239(3) A, c=24.689(2) A for EuAg{sub 4}Sb{sub 2}), which can be derived from the trigonal CaAl{sub 2}Si{sub 2}-type structure of the isoelectronic zinc-containing pnictides AZn{sub 2}Pn{sub 2} by insertion of additional Ag atoms into trigonal planar sites within [M{sub 2}Pn{sub 2}]{sup 2-} slabs built up of edge-sharing tetrahedra. Band structure calculations on SrAg{sub 4}As{sub 2} and SrAg{sub 4}Sb{sub 2} revealed that these charge-balanced Zintl phases actually exhibit no gap at the Fermi level and are predicted to be semimetals. - Graphical abstract: SrAg{sub 4}As{sub 2} and related pnictides adopt a CaCu{sub 4}P{sub 2}-type structure in which additional Ag atoms enter trigonal planar sites within slabs built from edge-sharing tetrahedra. Highlights: Black-Right-Pointing-Pointer AAg{sub 4}Pn{sub 2} are the first Ag-containing members of the CaCu{sub 4}P{sub 2}-type structure. Black-Right-Pointing-Pointer Ag atoms are stuffed in trigonal planar sites within CaAl{sub 2}Si{sub 2}-type slabs. Black-Right-Pointing-Pointer Ag-Ag bonding develops through attractive d{sup 10}-d{sup 10} interactions.

Aging Mechanisms and Nondestructive Aging Indicator of Filled Cross-linked Polyethylene (XLPE) Exposed to Simultaneous Thermal and Gamma Radiation

Energy Technology Data Exchange (ETDEWEB)

Liu, Shuaishuai; Fifield, Leonard S.; Bowler, Nicola

2018-04-11

Aging mechanisms and a nondestructive aging indicator of filled cross-linked polyethylene (XLPE) cable insulation material used in nuclear power plants (NPPs) are studied. Using various material characterization techniques, likely candidates and functions for the main additives in a commercial filled-XLPE insulation material have been identified. These include decabromodiphenyl ether and Sb2O3 as flame retardants, ZnS as white pigment and polymerized 1,2-dihydro-2,2,4-trimethylquinoline as antioxidant. Gas chromatography-mass spectrometry, differential scanning calorimetry, oxidation induction time and measurements of dielectric loss tangent are utilized to monitor property changes as a function of thermal and radiation exposure of the cable material. Small-molecular-weight hydrocarbons are evolve with gamma radiation aging at 90 °C. The level of antioxidant decreases with aging by volatilization and chemical reaction with free radicals. Thermal aging at 90 °C for 25 days or less causes no observable change to the cross-linked polymer structure. Gamma radiation causes damage to crystalline polymer regions and introduces defects. Dielectric loss tangent is shown to be an effective and reliable nondestructive indicator of the aging severity of the filled-XLPE insulation material.

Systematic features of the structure of the heavy odd-mass Sb nuclides near the N = 82 closed shell

International Nuclear Information System (INIS)

Stone, C.A.; Robertson, J.D.; Faller, S.H.; Mantica, P.F.; Zimmerman, B.E.; Chung Chien; Walters, W.B.

1995-01-01

New data for the decay of 4.1 min 3/2 + 127 Sn to levels of 127 Sb, decay of 2.2 min 3/2 + 129 Sn to levels of 12 Sb and decay of ∼60 s 3/2 + 131 Sn to levels of 131 Sb are presented. The shift in level positions arising from the monopole interaction and core phonon structure as well as changes in beta decay patterns are discussed. (orig.)

Sb,123121 nuclear quadrupole resonance as a microscopic probe in the Te-doped correlated semimetal FeSb2: Emergence of electronic Griffith phase, magnetism, and metallic behavior

Science.gov (United States)

Gippius, A. A.; Zhurenko, S. V.; Hu, R.; Petrovic, C.; Baenitz, M.

2018-02-01

Sb,123121 nuclear quadrupole resonance (NQR) was applied to Fe(Sb1-xTex)2 in the low doping regime (x =0 , 0.01, and 0.05) as a microscopic zero field probe to study the evolution of 3 d magnetism and the emergence of metallic behavior. Whereas the NQR spectra itself reflects the degree of local disorder via the width of the individual NQR lines, the spin lattice relaxation rate (SLRR) 1 /T1(T ) probes the fluctuations at the Sb site. The fluctuations originate either from conduction electrons or from magnetic moments. In contrast to the semimetal FeSb2 with a clear signature of the charge and spin gap formation in 1 /T1(T ) T [˜exp/(Δ kBT ) ] , the 1% Te-doped system exhibits almost metallic conductivity and the SLRR nicely confirms that the gap is almost filled. A weak divergence of the SLRR coefficient 1 /T1(T ) T ˜T-n˜T-0.2 points towards the presence of electronic correlations towards low temperatures. This is supported by the electronic specific heat coefficient γ =(Cel/T ) showing a power-law divergence γ (T ) ˜T-m˜(1/T1T ) 1 /2˜T-n /2˜Cel/T which is expected in the renormalized Landau Fermi liquid theory for correlated electrons. In contrast to that the 5% Te-doped sample exhibits a much larger divergence in the SLRR coefficient showing 1 /T1(T ) T ˜T-0.72 . According to the specific heat divergence a power law with n =2 m =0.56 is expected for the SLRR. This dissimilarity originates from admixed critical magnetic fluctuations in the vicinity of antiferromagnetic long range order with 1 /T1(T ) T ˜T-3 /4 behavior. Furthermore Te-doped FeSb2 as a disordered paramagnetic metal might be a platform for the electronic Griffith phase scenario. NQR evidences a substantial asymmetric broadening of the Sb,123121 NQR spectrum for the 5% sample. This has a predominant electronic origin in agreement with the electronic Griffith phase and stems probably from an enhanced Sb-Te bond polarization and electronic density shift towards the Te atom inside Sb

Phase transitions in thin films of Sn-Sb-Se system

International Nuclear Information System (INIS)

Samsudi Sakrani; Abdalla Belal Adam; Yussof Wahab

1998-01-01

The preparation and formation of covalent ternary Sn-Sb-Se system were investigated. A solid state reaction technique was employed whereby the evaporated multilayers of Sn/Se/Sb/Sn reacted chemically at a fixed temperature of 240 o C and were allowed to a room temperature slow-cooling. X-ray diffraction analysis showed that phase changes occurred in the system, with indication of amorphization for the predicted Sn 9 .3Sb 8 .1Se 4 4.9 and Sn 1 3.2Sb 4 3.4Se 4 3.4 compositions. These enabled the preliminary topological phase transitions of Sn-Sb-Se system according to the Gibb's triangle in which the areas of crystalline-amorphous were located. (Author)

Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

International Nuclear Information System (INIS)

Zhao Jing; Liang Jingjing; Pan Yingli; Zhang Yong; Jia Dingxian

2011-01-01

Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en) 2 (dien)(η 2 -SbSe 4 )] (Ln=Ce(1a), Nd(1b)), [Ln(en) 2 (dien)(SbSe 4 )] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)(μ-η 1 ,η 2 -SbSe 4 )] ∞ (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)(η 2 -SbSe 4 )] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe 4 ] 3- acts as a monodentate ligand mono-SbSe 4 , a bidentate chelating ligand η 2 -SbSe 4 or a tridentate bridging ligand μ-η 1 ,η 2 -SbSe 4 to the lanthanide(III) center depending on the Ln 3+ ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E g between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: → Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. → The [SbSe 4 ] 3- anion acts as a mono-SbSe 4 , a η 2 -SbSe 4 or a μ-η 1 ,η 2 -SbSe 4 ligand to the Ln 3+ ions. → The soft base ligand [SbSe 4 ] 3- can be controlled to coordinate to the Ln 3+ ions with en+dien and en+trien as co-ligands.

Analysis of the 4d7 (4f + 6p) and 4p54d9 configurations of Sn VII, Sb VIII and Te IX

International Nuclear Information System (INIS)

Azarov, V.I.; Joshi, Y.N.; Churilov, S.S.; Ryabtsev, A.N.

1994-01-01

The spectra of tin, antimony and tellerium were photographed in the 120-200 A region on 10.7 m and 3 m grazing incidence spectrographs using a triggered spark source. The 4d 8 -4d 7 (4f + 6p) + 4p 5 4d 9 transitions of Sn VII, Sb VIII and Te IX were investigated. In the Sn VII spectrum 109 new lines were classified in the 152-192 A region and 34 new levels were established, in the Sb VIII spectrum 78 new lines were classified in the 138-158 A region and 21 new levels were established, and in the Te IX 76 new lines were classified in the 121-139 A region and 21 new levels were established. Strong configuration interaction among the 4d 7 (np + mf), and 4p 5 4d 9 (n = 5, 6; m = 4, 5) configurations was observed. Least-squares-fitting (LSF) parametric calculations involving configuration interaction were carried out to interpret the observed spectra. (orig.)

Effects of the co-addition of LiSbO3-LiTaO3 on the densification of (Na1/2K1/2)NbO3 lead free ceramics by atmosphere sintering

International Nuclear Information System (INIS)

Jiang Na; Fang Bijun; Wu Jian; Du Qingbo

2011-01-01

Research highlights: → This manuscript shows a synthesis method that can easily obtain excellent lead-free samples, which is valuable for industrial production. → Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics with high relative density, being 94.73%, and excellent integral electrical properties, piezoelectric constant d 33 being 228 pC/N, were prepared by atmosphere sintering method. Which can be attributed to the co-doping of LiSbO 3 -LiTaO 3 . - Abstract: Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics were prepared by the conventional solid-state reaction method. Due to the co-addition of LiSbO 3 -LiTaO 3 , the 0.94NKN-0.03LS-0.03LT ceramics prepared by atmosphere sintering at 1040 deg. C exhibit high relative density, being 94.73%, and rather homogenous microstructure. X-ray diffraction (XRD) measurement confirmed that the sintered ceramics exhibit pure tetragonal perovskite structure. The 0.94NKN-0.03LS-0.03LT ceramics exhibit excellent integral electrical properties, in which the value of piezoelectric constant d 33 is 228 pC/N, the electromechanical coupling factors K p and K t are 0.220 and 0.230, respectively, the mechanical quality factor Q m is 32.19, and the remnant polarization P r is 23.06 μC/cm 2 . Such excellent electrical properties are considered as correlating with the high relative density of the synthesized ceramics induced by the co-doping of LiSbO 3 -LiTaO 3 .

A 121Sb Moessbauer Study of the Chemical State of Antimony in V-Sb-O Mixed-Oxide Catalysts for the Ammoxidation of Propane

International Nuclear Information System (INIS)

Stievano, L.; Wagner, F. E.; Zanthoff, H. W.; Calogero, S.

2002-01-01

The structural changes of two representative samples of a group of V-Sb-oxide catalysts, a vanadium-rich and an antimony-rich specimen, are investigated by 121 Sb Moessbauer spectroscopy after treatment under propene or hydrogen at 673 K. The as-prepared catalysts contain both Sb(V) and Sb(III) as crystalline and microcrystalline α-Sb 2 O 4 and VSbO 4 , as well as an additional amorphous V 5+ oxide phase. The oxidation state of antimony does not change upon exposure to propene, whereas a partial reduction can be obtained by a more intense reduction under hydrogen. The Moessbauer results indicate that the antimony in VSbO 4 can be reduced more easily than that in α-Sb 2 O 4 , which appears to be more stable. These results are discussed in view of the observed depletion of vanadium at the surface of the catalyst particles under reaction conditions.

Limiting scattering processes in high-mobility InSb quantum wells grown on GaSb buffer systems

Science.gov (United States)

Lehner, Ch. A.; Tschirky, T.; Ihn, T.; Dietsche, W.; Keller, J.; Fält, S.; Wegscheider, W.

2018-05-01

We present molecular beam epitaxial grown single- and double-side δ -doped InAlSb/InSb quantum wells with varying distances down to 50 nm to the surface on GaSb metamorphic buffers. We analyze the surface morphology as well as the impact of the crystalline quality on the electron transport. Comparing growth on GaSb and GaAs substrates indicates that the structural integrity of our InSb quantum wells is solely determined by the growth conditions at the GaSb/InAlSb transition and the InAlSb barrier growth. The two-dimensional electron gas samples show high mobilities of up to 349 000 cm2/Vs at cryogenic temperatures and 58 000 cm2/Vs at room temperature. With the calculated Dingle ratio and a transport lifetime model, ionized impurities predominantly remote from the quantum well are identified as the dominant source of scattering events. The analysis of the well-pronounced Shubnikov-de Haas oscillations reveals a high spin-orbit coupling with an effective g -factor of -38.4 in our samples. Along with the smooth surfaces and long mean free paths demonstrated, our InSb quantum wells are increasingly competitive for nanoscale implementations of Majorana mode devices.

Radiation-modified structure of Ge25Sb15S60 and Ge35Sb5S60 glasses

International Nuclear Information System (INIS)

Kavetskyy, T.; Shpotyuk, O.; Kaban, I.; Hoyer, W.

2008-01-01

Atomic structures of Ge 25 Sb 15 S 60 and Ge 35 Sb 5 S 60 glasses are investigated in the γ-irradiated and annealed after γ-irradiation states by means of high-energy synchrotron x-ray diffraction technique. The first sharp diffraction peak (FSDP) is detected at around 1.1 A -1 in the structure factors of both alloys studied. The FSDP position is found to be stable for radiation/annealing treatment of the samples, while the FSDP intensity shows some changes between γ-irradiated and annealed states. The peaks in the pair distribution functions observed between 2 and 4 A are related to the Ge-S, Ge-Sb, and Sb-Sb first neighbor correlations and Ge-Ge second neighbor correlations in the edge-shared GeS 4/2 tetrahedra, and S-S and/or Ge-Ge second neighbor correlations in the corner-shared GeS 4/2 tetrahedra. Three mechanisms of the radiation-/annealing-induced changes are discussed in the framework of coordination topological defect formation and bond-free solid angle concepts

Cinnamic acid 4-hydroxylase of sorghum [Sorghum biocolor (L.) Moench] gene SbC4H1 restricts lignin synthesis in Arabidopsis

Science.gov (United States)

Cinnamic acid 4-hydroxylase (C4H) is the first hydroxylase enzyme of the phenylpropanoid pathway, and its content and activity affects the lignin synthesis. In this study, we isolated a C4H gene SbC4H1 from the suppression subtractive hybridization library of brown midrib (bmr) mutants of Sorghum b...

Structural transitions, ion mobility, and conductivity in CsSbF3(H2PO4)

Science.gov (United States)

Kavun, V. Ya.; Uvarov, N. F.; Slobodyuk, A. B.; Ulihin, A. S.; Kovaleva, E. V.; Zemnukhova, L. A.

2018-02-01

Structural transitions, ion mobility, and conductivity in CsSbF3(H2PO4) (I) have been investigated by the methods of 1H, 19F, 31P NMR (including 1H, 19F, 31P MAS NMR), DSC, X-ray diffraction, and impedance spectroscopy. It was found that the fundamental changes in 1H, 19F, 31P NMR spectra (above 390 K) were associated with the formation of a crystalline disorder phase I with high ionic mobility in the proton and fluoride sublattices, as a result of a phase transition in the 400-420 K range. In the same temperature range, the transition of PO2(OH)2- anions from the "rigid lattice" to fast reorientations takes place. Above 430 K, there occurs a transition from the crystalline disordered phase to the amorphous one. The types of ion mobility in CsSbF3(H2PO4) and its amorphous phase have been established and temperature ranges of their realization have been determined (150-450 K). According to the NMR data, the diffusion in the proton sublattice of the disordered crystalline and amorphous phases is preserved even at room temperature. The ionic conductivity in CsSbF3(H2PO4) reaches the values of 2.6 × 10-4 S/cm in the temperature range 410-425 K and decreases down to 2.0 × 10-5 S/cm upon transition to the amorphous phase (435-445 K).

Phase diagrams of novel Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2}–Tl{sub 2}SnSe{sub 3} quasi-ternary system following DTA and X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Barchiy, I.E.; Tatzkar, A.R. [Department of Chemistry, Uzhgorod National University, Pidgirna St., 46, Uzhgorod 88000 (Ukraine); Fedorchuk, A.O. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, Pekarska St., 50, Lviv 79010 (Ukraine); Plucinski, K., E-mail: kpluc2006@wp.pl [Electronics Department, Military University Technology, Warsaw, Kaliskiego 2, Warsaw 00-908 (Poland)

2016-06-25

Phase relation in the Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2}–Tl{sub 2}SnSe{sub 3} quasiternary system were studied by the DTA and X-ray diffraction in combination with mathematical modeling. The phase diagrams of the Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2} and Tl{sub 2}SnSe{sub 3}–TlSbSe{sub 2} systems, the perspective views of the phase interaction in the ternary system, the liquidus surface projection, the isothermal section at 423 K were built for the first time. The Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2}–Tl{sub 2}SnSe{sub 3} system is of the invariant eutectic type and is characterized by the formation of limited solid solutions following initial ternary compounds. New complex compounds are not formed. - Highlights: • Two Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2},Tl{sub 2}SnSe{sub 3}–TlSbSe{sub 2} systems were explored. • Invariant processes in the ternary system were determined. • New complex compounds were not observed in ternary system.

InSb semiconductors and (In,Mn)Sb diluted magnetic semiconductors. Growth and properties

Energy Technology Data Exchange (ETDEWEB)

Tran, Lien

2011-04-13

This dissertation describes investigations of the growth by molecular beam epitaxy and the characterization of the semiconductor InSb as well as the diluted magnetic semiconductor (DMS) In{sub 1-x}Mn{sub x}Sb. The InSb films were grown on GaAs (001) substrate and Si (001) offcut by 4 toward (110) substrate up to a thickness of about 2 {mu}m, in spite of a large lattice mismatch between the epi-layer and substrate (14.6% between InSb and GaAs, and 19.3% between InSb and Si). After optimizing the growth conditions, the best InSb films grown directly on GaAs without any special technique results in a high crystal quality, low noise, and an electron mobility of 41100 cm{sup 2}/V s Vs with associated electron concentration of 2.9.10{sup 6} cm{sup -3} at 300 K. Such structures could be used, for example, for infrared detector structures. The growth of InSb on Si, however, is a challenge. In order to successfully grow InSb on Si, tilted substrates and the insertion of buffer layers were used, which helps to reduce the lattice mismatch as well as the formation of defects, and hence to improve the crystal quality. An electron mobility of 24000 cm{sup 2}/V s measured at 300 K, with an associated carrier concentration of 2.6.10{sup 1}6 cm{sup -3} is found for the best sample that was grown at 340 C with a 0.06 {mu}m-thick GaSb/AlSb superlattice buffer layer. The smaller value of electron mobility (compared to the best GaAsbased sample) is related to a higher density of microtwins and stacking faults as well as threading dislocations in the near-interface region as shown by transmission electron microscopy. Deep level noise spectra indicate the existence of deep levels in both GaAs and Si-based samples. The samples grown on Si exhibit the lowest Hooge factor at 300 K, lower than the samples grown on GaAs. Taking the optimized growth conditions of InSb/GaAs, the diluted magnetic semiconductor In{sub 1-x}Mn{sub x}Sb/GaAs (001) is prepared by adding a few percent of Mn into the

Quaternary InGaAsSb Thermophotovoltaic Diode Technology

International Nuclear Information System (INIS)

M Dashiell; J Beausang; H Ehsani; G Nichols; D DePoy; L Danielson; P Talamo; K Rahner; E Brown; S Burger; P Fourspring; W Topper; P Baldasaro; C Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; Jizhong Li; R Martinelli; D Donetski; S Anikeev; G Belenky; S Luryl

2005-01-01

Thermophotovoltaic (TPV) diodes fabricated from InGaAsSb alloys lattice-matched to GaSb substrates are grown by Metal Organic Vapor Phase Epitaxy (MOVPE). 0.53eV InGaAsSb TPV diodes utilizing front-surface spectral control filters have been tested in a vacuum cavity and a TPV thermal-to-electric conversion efficiency (η TPV ) and a power density (PD) of η TPV = 19% and PD=0.58 W/cm 2 were measured for T radiator = 950 C and T diode = 27 C. Recombination coefficients deduced from minority carrier measurements and the theory reviewed in this article predict a practical limit to the maximum achievable conversion efficiency and power density for 0.53eV InGaAsSb TPV. The limits for the above operating temperatures are projected to be η TPV = 26% and PD = 0.75 W/cm 2 . These limits are extended to η TPV = 30% and PD = 0.85W/cm 2 if the diode active region is bounded by a reflective back surface to enable photon recycling and a two-pass optical path length. The internal quantum efficiency of the InGaAsSb TPV diode is close to the theoretically predicted limits, with the exception of short wavelength absorption in GaSb contact layers. Experiments show that the open circuit voltage of the 0.53eV InGaAsSb TPV diodes is not strongly dependent on the device architectures studied in this work where both N/P and P/N double heterostructure diodes have been grown with various acceptor and donor doping levels, having GaSb and AlGaAsSb confinement, and also partial back surface reflectors. Lattice matched InGaAsSb TPV diodes were fabricated with bandgaps ranging from 0.6 to 0.5eV without significant degradation of the open circuit voltage factor, quantum efficiency, or fill factor as the composition approached the miscibility gap. The key diode performance parameter which is limiting efficiency and power density below the theoretical limits in InGaAsSb TPV devices is the open circuit voltage. The open circuit voltages of state-of-the-art 0.53eV InGaAsSb TPV diode are ∼10

3+ and [Sb13Se16Br2] 5+ - Double and quadruple spiro cubanes from ionic liquids

KAUST Repository

Ahmed, Ejaz

2014-01-08

The reaction of antimony and selenium in the bromine-rich Lewis acidic ionic liquid [BMIm]Br·4.7AlBr3 (BMIm: 1-butyl-3- methylimidazolium) in the presence of a small amount of NbCl5 at 160 °C yielded dark-red crystals of [Sb7Se8Br 2][AlX4]3. For X = Cl0.15(1)Br 0.85(1), the compound is isostructural to [Sb7S 8Br2][AlCl4]3 [P212 121, a = 12.5132(5) Å, b = 17.7394(6) Å, c = 18.3013(6) Å]. For a higher chlorine content, X = Cl 0.58(1)Br0.42(1), a slightly disordered variant with a bisected unit cell is found [P21212, a = 12.3757(3) Å, b = 17.4116(5) Å, c = 9.0420(2) Å]. The [Sb 7Se8Br2]3+ heteropolycation (C 2 symmetry) is a spiro double-cubane with an antimony atom on the shared corner. From this distorted octahedrally coordinated central atom, tricoordinate selenium and antimony atoms alternate in the bonding sequence. The terminal antimony atoms each bind to a bromine atom. Quantum chemical calculations confirm polar covalent Sb-Se bonding within the cubes and indicate three-center, four-electron bonds for the six-coordinate spiro atoms. The calculated charge distribution reflects the electron-donor role of the antimony atoms. The use of a chlorine-rich ionic liquid resulted in the formation of triclinic [Sb13Se16Br2][AlX4] 5 with X = Cl0.80(1)Br0.20(1) [P$\\\\bar {1}$, a = 9.0842(5) Å, b = 19.607(1) Å, c = 21.511(1) Å, α = 64.116(6), β = 79.768(7), γ = 88.499(7)]. The cationic cluster [Sb13Se16Br2]5+ is a bromine-terminated spiro quadruple-cubane. This 31 atom concatenation of four cubes is assumed to be the largest known discrete main group polycation. A similar reaction in a chloride-free system yielded [Sb7Se 8Br2][Sb13Se16Br2] [AlBr4]8. In its monoclinic structure [P2/c, a = 27.214(5) Å, b = 9.383(2) Å, c = 22.917(4) Å, β = 101.68(1)], the two types of polycations alternate in layers along the a axis. In the series [Sb4+3nSe4+4nBr2](2+n)+, these cations are the members with n = 1 and 3. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGa

Room-temperature broadband InAsSb flip-chip photodiodes with {lambda}{sub cutoff} = 4.5 {mu}m

Energy Technology Data Exchange (ETDEWEB)

Zakhgeim, A L [Russian Academy of Sciences, Scientific-Technological Center for Microelectronics and Submicron Heterostructures at Ioffe Physicotechnical Institute (Russian Federation); Zotova, N V; Il' inskaya, N D; Karandashev, S A; Matveev, B. A., E-mail: bmat@iropt3.ioffe.rssi.ru; Remennyi, M A; Stus' , N M [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Chernyakov, A E [Russian Academy of Sciences, Scientific-Technological Center for Microelectronics and Submicron Heterostructures at Ioffe Physicotechnical Institute (Russian Federation)

2009-03-15

Equilibrium and nonequilibrium IR images of p-InAsSbP/n-InAsSb/n{sup +}-InAs photodiodes including the images obtained in the electroluminescence and negative luminescence modes have been analyzed. The contact reflectivity has been evaluated. The influence of the substrate's doping level and mesa depth on the quantum efficiency and sensitivity of a backside illuminated photodiode sensitive in the 2.7-4.5 {mu}m range is discussed.

Growth and characterization of an InSb infrared photoconductor on Si via an AlSb/GaSb buffer

Science.gov (United States)

Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt

2018-05-01

A 99.6% relaxed InSb layer is grown on a 6° offcut (1 0 0) Si substrate via an AlSb/GaSb buffer using molecular beam epitaxy (MBE). A 200 nm GaSb buffer is first grown on Si and the lattice mismatch between them is accommodated by an interfacial misfit (IMF) array consisting of uniformly distributed 90° misfit dislocations. Si delta doping is introduced during the growth of GaSb to reduce the density of threading dislocation. Subsequently, a 50 nm AlSb buffer is grown followed by a 0.8 μm InSb layer. The InSb layer exhibits a 300 K electron mobility of 22,300 cm2/Vs. An InSb photoconductor on Si is demonstrated with a photoconductive gain from 77 K to 200 K under a 700 °C maintained blackbody.

Eu{sub 7}Ga{sub 6}Sb{sub 8}: A Zintl phase with Ga-Ga bonds and polymeric gallium antimonide chains

Energy Technology Data Exchange (ETDEWEB)

Park, S -M; Kim, S -J; Kanatzidis, M G

2004-08-01

The Zintl phase Eu{sub 7}Ga{sub 6}Sb{sub 8} was obtained from a direct element combination reaction at 900 deg. C. It crystallizes in the orthorhombic space group Pbca (No. 61) with a=15.6470(17) A, b=17.2876(19) A, c=17.9200(19) A, and Z=8. In Eu{sub 7}Ga{sub 6}Sb{sub 8}, the anionic framework forms infinite chains of [Ga{sub 6}Sb{sub 8}]{sup 14-} which are arranged side by side to make a sheet-like arrangement but without linking. The sheets of chains are separated by Eu{sup 2+} atoms and also within the sheet, Eu{sup 2+} atoms fill the spaces between two chains. The chain is made up of homoatomic tetramers (Ga{sub 4}){sup 6+} and dimers (Ga{sub 2}){sup 4+} connected by Sb atoms. The compound is a narrow band-gap semiconductor with E{sub g}{approx}0.6 eV and satisfies the classical Zintl concept. Extended Hueckel band structure calculations confirm that the material is a semiconductor and suggest that the structure is stabilized by strong Ga-Ga covalent bonding interactions. Magnetic susceptibility measurements for Eu{sub 7}Ga{sub 6}Sb{sub 8} show that the Eu atoms are divalent and the compound has an antiferromagnetic transition at 9 K.

InSb semiconductors and (In,Mn)Sb diluted magnetic semiconductors: Growth and properties

International Nuclear Information System (INIS)

Tran, Lien

2011-01-01

This dissertation describes investigations of the growth by molecular beam epitaxy and the characterization of the semiconductor InSb as well as the diluted magnetic semiconductor (DMS) In 1-x Mn x Sb. The InSb films were grown on GaAs (001) substrate and Si (001) offcut by 4 toward (110) substrate up to a thickness of about 2 μm, in spite of a large lattice mismatch between the epi-layer and substrate (14.6% between InSb and GaAs, and 19.3% between InSb and Si). After optimizing the growth conditions, the best InSb films grown directly on GaAs without any special technique results in a high crystal quality, low noise, and an electron mobility of 41100 cm 2 /V s Vs with associated electron concentration of 2.9.10 6 cm -3 at 300 K. Such structures could be used, for example, for infrared detector structures. The growth of InSb on Si, however, is a challenge. In order to successfully grow InSb on Si, tilted substrates and the insertion of buffer layers were used, which helps to reduce the lattice mismatch as well as the formation of defects, and hence to improve the crystal quality. An electron mobility of 24000 cm 2 /V s measured at 300 K, with an associated carrier concentration of 2.6.10 1 6 cm -3 is found for the best sample that was grown at 340 C with a 0.06 μm-thick GaSb/AlSb superlattice buffer layer. The smaller value of electron mobility (compared to the best GaAsbased sample) is related to a higher density of microtwins and stacking faults as well as threading dislocations in the near-interface region as shown by transmission electron microscopy. Deep level noise spectra indicate the existence of deep levels in both GaAs and Si-based samples. The samples grown on Si exhibit the lowest Hooge factor at 300 K, lower than the samples grown on GaAs. Taking the optimized growth conditions of InSb/GaAs, the diluted magnetic semiconductor In 1-x Mn x Sb/GaAs (001) is prepared by adding a few percent of Mn into the host material InSb during growth. I have

Shear Bond Strengths and Morphological Evaluation of Filled and Unfilled Adhesive Interfaces to Enamel and Dentine

Science.gov (United States)

Mortazavi, Vajihesadat; Fathi, Mohammadhosein; Ataei, Ebrahim; Khodaeian, Niloufar; Askari, Navid

2012-01-01

In this laboratory study shear bond strengths of three filled and one unfilled adhesive systems to enamel and dentine were compared. Forty-eight extracted intact noncarious human mandibular molars were randomly assigned to two groups of 24 one for bonding to enamel and the other for bonding to dentine. Buccal and lingual surfaces of each tooth were randomly assigned for application of each one of filled (Prime & Bond NT (PBNT), Optibond Solo Plus (OBSP), and Clearfil SE Bond (CSEB)) and unfilled (Single Bond (SB)) adhesive systems (n = 12). A universal resin composite was placed into the translucent plastic cylinders (3 mm in diameter and 2 mm in length) and seated against the enamel and dentine surfaces and polymerized for 40 seconds. Shear bond strength was determined using a universal testing machine, and the results were statistically analyzed using two-way ANOVA, one-way ANOVA, t-test, and Tukey HSD post hoc test with a 5% level of significance.There were no statistically significant differences in bond strength between the adhesive systems in enamel, but CSEB and SB exhibited significantly higher and lower bond strength to dentine, respectively, than the other tested adhesive systems while there were no statistically significant differences between PBNT and OBSP. PMID:23209471

Shear Bond Strengths and Morphological Evaluation of Filled and Unfilled Adhesive Interfaces to Enamel and Dentine

Directory of Open Access Journals (Sweden)

Vajihesadat Mortazavi

2012-01-01

Full Text Available In this laboratory study shear bond strengths of three filled and one unfilled adhesive systems to enamel and dentine were compared. Forty-eight extracted intact noncarious human mandibular molars were randomly assigned to two groups of 24 one for bonding to enamel and the other for bonding to dentine. Buccal and lingual surfaces of each tooth were randomly assigned for application of each one of filled (Prime & Bond NT (PBNT, Optibond Solo Plus (OBSP, and Clearfil SE Bond (CSEB and unfilled (Single Bond (SB adhesive systems (n=12. A universal resin composite was placed into the translucent plastic cylinders (3 mm in diameter and 2 mm in length and seated against the enamel and dentine surfaces and polymerized for 40 seconds. Shear bond strength was determined using a universal testing machine, and the results were statistically analyzed using two-way ANOVA, one-way ANOVA, t-test, and Tukey HSD post hoc test with a 5% level of significance.There were no statistically significant differences in bond strength between the adhesive systems in enamel, but CSEB and SB exhibited significantly higher and lower bond strength to dentine, respectively, than the other tested adhesive systems while there were no statistically significant differences between PBNT and OBSP.

First-principles study lone-pair effects of Sb (III)-S chromophore influence on SHG response in quaternary potassium containing silver antimony sulfides

Energy Technology Data Exchange (ETDEWEB)

Huang, Junben [Key Laboratory of Functional Materials and Devices for Special Environments of CAS,, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi 830011 (China); School of Physics Science and Technology, Xinjiang University, Urumqi 830046 (China); Su, Xin; Hou, Dianwei; Lei, Binghua [Key Laboratory of Functional Materials and Devices for Special Environments of CAS,, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Zhihua, E-mail: zhyang@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments of CAS,, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi 830011 (China); Pan, Shilie, E-mail: slpan@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments of CAS,, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi 830011 (China)

2017-05-15

First-principles studies of the geometric structures, electronic structures and optical properties of non-centrosymmetrical (NCS) KAg{sub 2}SbS{sub 4}, K{sub 2}AgSbS{sub 4} and K{sub 2}Ag{sub 3}Sb{sub 3}S{sub 7} and centrosymmetrical (CS) KAg{sub 2}SbS{sub 3} and K{sub 3}Ag{sub 9}Sb{sub 4}S{sub 12} have been performed by means of density functional theory. It is indicated that although they have similarity in their anionic groups and, the electronic structures, prominent features of the optical anisotropy or second-order nonlinear optical (NLO) susceptibilities are apparently different. The calculated birefringences are 0.0537, 0.0343, 0.1324, 0.2217 and 0.0604 which are attributed to the different anionic groups [SbS{sub 3}] and triangles [AgS{sub 3}]. Also, the calculated NLO responses are about 0.5×, 1.0× and 2.0× times than that commercial AgGaS{sub 2} (AGS, d{sub 36}=11 pm/V) for K{sub 2}AgSbS{sub 4}, KAg{sub 2}SbS{sub 4} and K{sub 2}Ag{sub 3}Sb{sub 3}S{sub 7}, respectively. In comparison with the absolute magnitude of second harmonic generation (SHG) coefficients, the order K{sub 2}Ag{sub 3}Sb{sub 3}S{sub 7}>KAg{sub 2}SbS{sub 4}>K{sub 2}AgSbS{sub 4} is clearly established in the SHG response. Further analysis based on the real-space atom-cutting method reveals that the main sources of the SHG properties of these compounds are from the Sb-S group, especially K{sub 2}Ag{sub 3}Sb{sub 3}S{sub 7} is mainly attributed to the lone pair stereochemical activity of Sb (III)-S group. - Graphical abstract: Compounds K{sub 2}AgSbS{sub 4}, KAg{sub 2}SbS{sub 4} and K{sub 2}Ag{sub 3}Sb{sub 3}S{sub 7} exhibit second-order NLO response: 15×, 30× and 62× times than that KDP (KH{sub 2}PO{sub 4}, d{sub 36}=0.39 pm/V), respectively. First-principles methods reveal that the large SHG response of K{sub 2}Ag{sub 3}Sb{sub 3}S{sub 7} is dominated by the Sb-S chromophore with lone pairs.

Optical response of confined excitons in GaInAsSb/GaSb Quantum Dots heterostructures

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Cano, R [Departamento de Fisica, Universidad Autonoma de Occidente, A.A. 2790, Cali (Colombia); Tirado-Mejia, L; Fonthal, G; Ariza-Calderon, H [Laboratorio de Optoelectronica, Universidad del Quindio, A.A. 4603 Armenia (Colombia); Porras-Montenegro, N, E-mail: rsanchez40@gmail.co [Departamento de Fisica, Universidad del Valle, A.A. 25360, Cali (Colombia)

2009-05-01

The narrow-gap Ga{sub 1-x}In{sub x}As{sub y}Sb{sub 1-y} compounds are suitable materials for heterostructure devices operating in the infrared wavelength range. In these compounds grown by liquid phase epitaxy over GaSb single crystals, for x and y values in the range of 0.10 to 0.14 for both variables, the photoluminescence optical response at 12K is blue-shifted by 20 meV related to the photoreflectance response. We believe this behavior is due to possible higher electronic confinement in some places of the heterostructure, possibly formed in the interface during the growth process. In order to explain this behavior, in this work we study the exciton recombination energy in spherical Quantum Dots (QDs) on Ga{sub 1-x}In{sub x}As{sub y}Sb{sub 1-y}/GaSb, using the variational procedure within the effective-mass approximation and considering an electron in a Type I band alignment formed by two semiconductors with similar parabolic conduction bands. Our results are in good agreement with recent experimental results.

27 CFR 4.46 - Certificate of nonstandard fill.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Certificate of nonstandard fill. 4.46 Section 4.46 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Requirements for Withdrawal of Wine From...

New antiferromagnetic semiconductor CuCr1.5Sb0.5S4

International Nuclear Information System (INIS)

Kesler, Ya.A.; Koroleva, L.I.; Mikheev, M.G.; Odintsov, A.G.; Filimonov, D.S.

1993-01-01

New halcogenide compound with spinel-antiferromagnetic semiconductor CuCr 1.5 Sb 0.5 S 4 are obtained and studied for the first time. Magnetic properties of this compound, namely, magnetization linear dependence, maximum on PHI(T) curve in the low-temperature area and realization of the Curie-Weis law for paramagnetic susceptibility with negative paramagnetic temperature testiby to the fact that this compound is antiferromagnetic

Electronic and magnetic properties of quasi-skutterudite PrCo2Ga8 compound

Science.gov (United States)

Ogunbunmi, Michael O.; Sondezi, Buyisiwe M.; Nair, Harikrishnan S.; Strydom, André M.

2018-05-01

PrCo2Ga8 is an orthorhombic quasi-skutterudite type compound which crystallizes in the CaCo2Al8 structure type, with space group Pbam (No. 55). The Pr3+ ion has a site symmetry of Cs which predicts a crystal electric field (CEF) level splitting into 9 singlets for J = 4. However, a phase transition at Tm = 1.28 K is observed in electrical resistivity and specific heat results and is reported in this paper. The electrical resistivity shows an upturn below Tm due to the superzone-gap formation. This transition is tuneable in fields and is suppressed to lower temperatures with applied magnetic fields. The electronic specific heat Cp(T) / T increases below Tm and reaches a value of 7.37 J/(mol K2) at 0.4 K. The Sommerfeld coefficient, γ extracted from the low temperature analysis of C4f(T) / T is 637 mJ/(mol K2) indicating a possible mass enhancement of the quasiparticles. The calculated entropy value of 3.05 J/(mol K) is recovered around Tm exhibiting almost 53% of Rln2, where R is the universal gas constant. Magnetic susceptibility results obeys the Curie-Weiss law for data above 100 K with an estimated effective magnetic moment, μeff = 3.37 μB/Pr and Weiss temperature, θp = -124 K.

Solution-Processed hybrid Sb2 S3 planar heterojunction solar cell

Science.gov (United States)

Huang, Wenxiao; Borazan, Ismail; Carroll, David

Thin-film solar cells based on inorganic absorbers permit a high efficiency and stability. Among or those absorber candidates, recently Sb2S3 has attracted extensive attention because of its suitable band gap (1.5eV ~1.7 eV) , strong optical absorption, low-cost and earth-abundant constituents. Currently high-efficiency Sb2S3 solar cells have absorber layer deposited on nanostructured TiO2 electrodes in combination with organic hole transport material (HTM) on top. However it's challenging to fill the nanostructured TiO2 layer with Sb2S3 and subsequently by HTM, this leads to uncovered surface permits charge recombination. And the existing of Sb2S3/TiO2/HTM triple interface will enhance the recombination due to the surface trap state. Therefore, a planar junction cell would not only have simpler structure with less steps to fabricate but also ideally also have a higher open circuit voltage because of less interface carrier recombination. By far there is limited research focusing on planar Sb2S3 solar cell, so the feasibility is still unclear. Here, we developed a low-toxic solution method to fabricate Sb2S3 thin film solar cell, then we studied the morphology of the Sb2S3 layer and its impact to the device performance. The best device with a structure of FTO/TiO2/Sb2S3/P3HT/Ag has PCE over 5% which is similar or higher than yet the best nanostructure devices with the same HTM. Furthermore, based on solution engineering and surface modification, we improved the Sb2S3 film quality and achieved a record PCE. .

Reactive ion etching of GaSb, (Al,Ga)Sb, and InAs for novel device applications

International Nuclear Information System (INIS)

LaTulipe, D.C.; Frank, D.J.; Munekata, H.

1991-01-01

Although a variety of novel device proposals for GaSb/(Al,Ga)Sb/InAs heterostructures have been made, relatively little is known about processing these materials. The authors of this paper have studied the reactive ion etching characteristics of GaSb, (Al,Ga)Sb, and InAs in both methane/hydrogen and chlorine gas chemistries. At conditions similar to those reported elsewhere for RIE of InP and GaAs in CH 4 /H 2 , the etch rate of (Al,Ga)Sb was found to be near zero, while GaSb and InAs etched at 200 Angstrom/minute. Under conditions where the etch mechanism is primarily physical sputtering, the three compounds etch at similar rates. Etching in Cl 2 was found to yield anistropic profiles, with the etch rate of (Al,Ga)Sb increasing with Al mole fraction, while InAs remains unetched. Damage to the InAs stop layer was investigated by sheet resistance and mobility measurements. These etching techniques were used to fabricate a novel InAs- channel FET composed of these materials. Several scanning electron micrographs of etching results are shown along with preliminary electrical characteristics

First-principles study of electronic structure of CuSbS{sub 2} and CuSbSe{sub 2} photovoltaic semiconductors

Energy Technology Data Exchange (ETDEWEB)

Maeda, T., E-mail: tmaeda@ad.ryukoku.ac.jp; Wada, T.

2015-05-01

We studied the features of CuSbS{sub 2} (CAS) and CuSbSe{sub 2} (CASe), two proposed photovoltaic compounds, and clarified their electronic structures by first-principles calculations and compared them to the chalcopyrite-type CuInSe{sub 2} results. For both CAS and CASe, the calculated enthalpies of formation of the chalcostibite phases were considerably lower than those of the chalcopyrite phases. Therefore, we considered that the chalcostibite phase is more stable for CAS and CASe. In their band structure calculated with the HSE06 hybrid functional, the valence band maxima of CAS and CASe were located at the Γ-point, and the conduction band minima were located at the R-point. Their second lowest conduction band was located at the Γ-point, whose energy level nearly equaled the R-point. For CAS (CASe), the partial density of the states shows the character of the Cu 3d and S 3p (Se 4p) orbitals at the top of the valence bands and the Sb 5p and S 3p (Se 4p) orbitals at the bottom of the conduction bands. The conduction bands of CAS and CASe have a p-orbital character (Sb 5p) that differs from the s-orbital character (In 5s) of CuInSe{sub 2}. It is for the reason that CAS and CASe do not have a chalcopyrite structure but a chalcostibite-type structure. The calculated absorption coefficient of CuSbS{sub 2} (10{sup 4}-10{sup 5} cm{sup −1}) is comparable to that of CuInSe{sub 2}. - Highlights: • We studied the features of CuSbS{sub 2} and CuSbSe{sub 2}, newly proposed photovoltaic compounds. • Chalcostibite phase is more stable in CuSbS{sub 2} and CuSbSe{sub 2}. • Band structures of CuSbS{sub 2} and CuSbS{sub 2} were calculated with HSE06 hybrid functional. • Absorption coefficient of chalcostibite-type CuSbS{sub 2} is comparable to that of CuInSe{sub 2}.

Breakdown of the quantum Hall effect in InAs/AlSb quantum wells due to counterflowing edge channels

NARCIS (Netherlands)

Wees, B.J. van; Meijer, G.I.; Kuipers, J.J.; Klapwijk, T.M.; Graaf, W. van de; Borghs, G.

1995-01-01

We investigated magnetotransport in the two-dimensional electron gas (2DEG) present in InAs/AlSb quantum wells. The filling factor Ng underneath a gate electrode was reduced relative to the bulk filling factor Nb. For Ng

Quantum Hall effect in InAs/AlSb double quantum well

International Nuclear Information System (INIS)

Yakunin, M.V.; Podgornykh, S.M.; Sadof'ev, Yu.G.

2009-01-01

Double quantum wells (DQWs) were first implemented in the InAs/AlSb heterosystem, which is characterized by a large Lande g factor |g|=15 of the InAs layers forming the well, much larger than the bulk g factor |g|=0.4 of the GaAs in conventional GaAs/AlGaAs DQWs. The quality of the samples is good enough to permit observation of a clear picture of the quantum Hall effect (QHE). Despite the small tunneling gap, which is due to the large barrier height (1.4 eV), features with odd filling factors ν=3,5,7, ... are present in the QHE, due to collectivized interlayer states of the DQW. When the field is rotated relative to the normal to the layers, the ν=3 state is suppressed, confirming the collectivized nature of that state and denying that it could owe its existence to a strong asymmetry of the DQW. Previously the destruction of the collectivized QHE states by a parallel field had been observed only for the ν=1 state. The observation of a similar effect for ν=3 in an InAs/AlSb DQW may be due to the large bulk g factor of InAs

Dissimilatory Sb(V) reduction by microorganisms isolated from Sb-contaminated sediment

Science.gov (United States)

Dovick, M. A.; Kulp, T. R.

2013-12-01

Mining and smelting are major sources of trace metal contamination in freshwater systems. Arsenic (As) is a common contaminant derived from certain mining operations and is a known toxic metalloid and carcinogen. Antimony (Sb) is listed as a pollutant of priority interest by the EPA and is presumed to share similar geochemical and toxicological properties with arsenic. Both elements can occur in four different oxidation states (V, III, 0, and -III) under naturally occurring conditions. In aqueous solutions As(V) and Sb(V) predominate in oxygenated surface waters whereas As(III) and Sb(III) are stable in anoxic settings. Numerous studies have examined microbiological redox pathways that utilize As(V) as a terminal electron acceptor for anaerobic respiration, however there have been few studies on microbial mechanisms that may affect the biogeochemical cycling of Sb in the environment. Here we report bacterial reduction of Sb(V) to Sb(III) in anoxic enrichment cultures and bacterial isolates grown from sediment collected from an Sb contaminated pond at a mine tailings site in Idaho (total pond water Sb concentration = 235.2 +/- 136.3 ug/L). Anaerobic sediment microcosms (40 mL) were established in artificial freshwater mineral salt medium, amended with millimolar concentrations of Sb(V), acetate or lactate, and incubated at 27°C for several days. Antimony(V), lactate, and acetate concentrations were monitored during incubation by High Performance Liquid Chromatography (HPLC) and Ion Chromatography (IC). Live sediment microcosms reduced millimolar amendments of Sb(V) to Sb(III) coupled to the oxidation of acetate and lactate, while no activity occurred in killed controls. Enrichment cultures were established by serially diluting Sb(V)-reducing microcosms in mineral salt medium with Sb(V) and acetate, and a Sb(V)-reducing bacterial strain was isolated by plating on anaerobic agar plates amended with millimolar Sb(V) and acetate. Direct cell counting demonstrated that

Design of thin InGaAsN(Sb) n-i-p junctions for use in four-junction concentrating photovoltaic devices

Science.gov (United States)

Wilkins, Matthew M.; Gupta, James; Jaouad, Abdelatif; Bouzazi, Boussairi; Fafard, Simon; Boucherif, Abderraouf; Valdivia, Christopher E.; Arès, Richard; Aimez, Vincent; Schriemer, Henry P.; Hinzer, Karin

2017-04-01

Four-junction solar cells for space and terrestrial applications require a junction with a band gap of ˜1 eV for optimal performance. InGaAsN or InGaAsN(Sb) dilute nitride junctions have been demonstrated for this purpose, but in achieving the 14 mA/cm2 short-circuit current needed to match typical GaInP and GaAs junctions, the open-circuit voltage (VOC) and fill factor of these junctions are compromised. In multijunction devices incorporating materials with short diffusion lengths, we study the use of thin junctions to minimize sensitivity to varying material quality and ensure adequate transmission into lower junctions. An n-i-p device with 0.65-μm absorber thickness has sufficient short-circuit current, however, it relies less heavily on field-aided collection than a device with a 1-μm absorber. Our standard cell fabrication process, which includes a rapid thermal anneal of the contacts, yields a significant improvement in diffusion length and device performance. By optimizing a four-junction cell around a smaller 1-sun short-circuit current of 12.5 mA/cm2, we produced an InGaAsN(Sb) junction with open-circuit voltage of 0.44 V at 1000 suns (1 sun=100 mW/cm2), diode ideality factor of 1.4, and sufficient light transmission to allow >12.5 mA/cm2 in all four subcells.

Magnetotransport of CaCu3Mn4O12 complex perovskite derivatives

International Nuclear Information System (INIS)

Sanchez-Benitez, J.; Andres, A. de; Garcia-Hernandez, M.; Alonso, J.A.; Martinez-Lope, M.J.

2006-01-01

Neutron powder diffraction, magnetic and magnetotransport studies were carried out on new derivatives of the CaCu 3 Mn 4 O 12 (A'A 3 B 4 O 12 ) complex perovskite. The samples were prepared in polycrystalline form under moderate pressure conditions. Substitutions at A and A' sites of CaCu 3 Mn 4 O 12 , with only Mn 4+ and insulating behavior, imply electron doping that affects the magnetic and transport properties. X-ray Absorption Spectroscopy showed that Mn 3+ /Mn 4+ valence mixing occurs only at B site, progressively filling the e g band and providing the metallic character in these compounds, as we observe in most of these samples. A semiconducting behavior is observed in samples with 50% Mn 3+ at B site. This can be understood by the opening of a gap in the conduction band corresponding to the half filling of the e g states. This is the case of the tetravalent rare earth doped samples (Ce and Th at A' site) and of the appropriate A site doped Ca(CuMn 2 )Mn 4 O 12 sample. At the strongly distorted A positions, Mn 3+ , with localized e g electrons, act as magnetic impurities at very low temperatures (<40 K) giving rise to the observed upturn in the resistivity. The magnetic origin of this scattering is evidenced by its drastic reduction under a magnetic field

Electrochemical properties and lithium ion diffusion in Li4FeSbO6 studied by first principle

Science.gov (United States)

Jia, Mingzhen; Wang, Hongyan; Wang, Hui; Chen, Yuanzheng; Guo, Chunsheng; Gan, Liyong

2017-10-01

Due to the high capacity, Li-rich materials Li2MO3 (M = transition metal) have attracted considerable attention as the next generation of Li-ion batteries. Li4FeSbO6 is a new Li-rich layered oxide material with antiferromagnet honeycomb structure. In this work, the electrochemical behavior, charging process and oxygen stability of LixFeSbO6 (0 ≤ xextracted, the charge compensation is mainly contributed by the oxygen atoms through analyzing the Bader charges of each element. In addition, oxygen evolution reactions will occur in LixFeSbO6 (x ≤ 1.5), which will decay the capacities during cycling process. Finally, we calculated that the lithium ion can diffuse in a three-dimensional pathway with the activation barriers from 0.36 eV to 0.67 eV.

Designing new lithium-excess cathode materials from percolation theory: nanohighways in Li(x)Ni(2-4x/3)Sb(x/3)O2.

Science.gov (United States)

Twu, Nancy; Li, Xin; Urban, Alexander; Balasubramanian, Mahalingam; Lee, Jinhyuk; Liu, Lei; Ceder, Gerbrand

2015-01-14

Increasing lithium content is shown to be a successful strategy for designing new cathode materials. In layered Li(x)Ni(2-4x/3)Sb(x/3)O2 (x = 1.00-1.15), lithium excess improves both discharge capacity and capacity retention at 1C. Structural studies reveal a complex nanostructure pattern of Li-Sb and Ni-Sb ordering where the interface between these domains forms the correct local configuration for good lithium mobility. The <1 nm Li-Sb stripe domains and their interfaces thereby effectively act as nanohighways for lithium diffusion.

Sb(III)-Imprinted Organic-Inorganic Hybrid Sorbent Prepared by Hydrothermal-Assisted Surface Imprinting Technique for Selective Adsorption of Sb(III)

Science.gov (United States)

Zhang, Dan; Zhao, Yue; Xu, Hong-Bo

2018-03-01

Sb(III)-imprinted organic-inorganic hybrid sorbent was prepared by hydrothermal-assisted surface imprinting technique and was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy coupled to an energy dispersive spectrometer and N2 adsorption/desorption isotherms. Hydrothermal-assisted process can improve the selectivity of the Sb(III)-imprinted hybrid sorbent for Sb(III) due to stable control of temperature and pressure. The Sb(III)-imprinted hybrid sorbent IIS indicated higher selectivity for Sb(III), had high static adsorption capacity of 37.3 mg g-1 for Sb(III), displayed stable adsorption capacity in pH range from 4 to 8, reached an rapid adsorption equilibrium within 30 min. According to the correlation coefficient ( r 2 > 0.99), the experimental data fitted better the pseudo-second-order kinetic model and Langmuir equilibrium isotherm.

Effect of electron-electron interaction on cyclotron resonance in high-mobility InAs/AlSb quantum wells

Energy Technology Data Exchange (ETDEWEB)

Krishtopenko, S. S., E-mail: sergey.krishtopenko@mail.ru; Gavrilenko, V. I. [Institute for Physics of Microstructures, Russian Academy of Sciences, 603950 Nizhny Novgorod, GSP-105 (Russian Federation); Lobachevsky State University, 23 Prospekt Gagarina, 603950 Nizhny Novgorod (Russian Federation); Ikonnikov, A. V. [Institute for Physics of Microstructures, Russian Academy of Sciences, 603950 Nizhny Novgorod, GSP-105 (Russian Federation); Orlita, M. [Laboratoire National des Champs Magnétiques Intenses (LNCMI-G), CNRS, 25 rue des Martyrs, B.P. 166, 38042 Grenoble (France); Sadofyev, Yu. G. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991, GSP-1, 53 Leninskiy Prospect (Russian Federation); Goiran, M. [Laboratoire National des Champs Magnétiques Intenses (LNCMI-T), CNRS, 143 Avenue de Rangueil, 31400 Toulouse (France); Teppe, F.; Knap, W. [Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, GIS-TERALAB, Universite Montpellier II, 34095 Montpellier (France)

2015-03-21

We report observation of electron-electron (e-e) interaction effect on cyclotron resonance (CR) in InAs/AlSb quantum well heterostructures. High mobility values allow us to observe strongly pronounced triple splitting of CR line at noninteger filling factors of Landau levels ν. At magnetic fields, corresponding to ν > 4, experimental values of CR energies are in good agreement with single-electron calculations on the basis of eight-band k ⋅ p Hamiltonian. In the range of filling factors 3 < ν < 4 pronounced, splitting of CR line, exceeding significantly the difference in single-electron CR energies, is discovered. The strength of the splitting increases when occupation of the partially filled Landau level tends to a half, being in qualitative agreement with previous prediction by MacDonald and Kallin [Phys. Rev. B 40, 5795 (1989)]. We demonstrate that such behaviour of CR modes can be quantitatively described if one takes into account both electron correlations and the mixing between conduction and valence bands in the calculations of matrix elements of e-e interaction.

Evaluation of the novel 5-HT4 receptor PET ligand [11C]SB207145 in the Gottingen minipig

DEFF Research Database (Denmark)

Kornum, B.R.; Lind, N.M.; Gillings, N.

2009-01-01

This study investigates 5-hydroxytryptamine 4 (5-HT(4)) receptor binding in the minipig brain with positron emission tomography (PET), tissue homogenate-binding assays, and autoradiography in vitro. The cerebral uptake and binding of the novel 5-HT(4) receptor radioligand [(11)C]SB207145 in vivo...... was modelled and the outcome compared with postmortem receptor binding. Different models for quantification of [(11)C]SB207145 binding were evaluated: One-tissue and two-tissue compartment kinetic modelling, Logan arterial input, and three different reference tissue models. We report that the pig...... model provides stable and precise estimates of the binding potential in all regions. The binding potentials calculated for striatum, midbrain, and cortex from the PET data were highly correlated with 5-HT(4) receptor concentrations determined in brain homogenates from the same regions, except...

Processing and nanostructure influences on mechanical properties of thermoelectric materials

Science.gov (United States)

Schmidt, Robert David

Thermoelectric (TE) materials are materials that can generate an electric current from a thermal gradient, with possible service in recovery of waste heat such as engine exhaust. Significant progress has been made in improving TE conversion efficiency, typically reported according to the figure of merit, ZT, with several recent papers publishing ZT values above 2. Furthermore, cost reductions may be made by the use of lower cost elements such as Mg, Si, Sn, Pb, Se and S in TE materials, while achieving ZT values between 1.3 and 1.8. To be used in a device, the thermoelectric material must be able to withstand the applied thermal and mechanical forces without failure. However, these materials are brittle, with low fracture toughness typically less than 1.5 MPa-m1/2, and often less than 0.5 MPa-m1/2. For comparison, window glass is approximately 0.75 MPa-m1/2. They have been optimized with nanoprecipitates, nanoparticles, doping, alterations in stoichiometry, powder processing and other techniques, all of which may alter the mechanical properties. In this study, the effect of SiC nanoparticle additions in Mg2Si, SnTe and Ag nanoparticle additions in the skutterudite Ba0.3Co 4Sb12 on the elastic moduli, hardness and fracture toughness are measured. Large changes (˜20%) in the elastic moduli in SnTe 1+x as a function of x at 0 and 0.016 are shown. The effect on mechanical properties of doping and precipitates of CdS or ZnS in a PbS or PbSe matrix have been reported. Changes in sintering behavior of the skutterudite with the Ag nanoparticle additions were explored. Possible liquid phase sintering, with associated benefits in lower processing temperature, faster densification and lower cost, has been shown. A technique has been proposed for determining additional liquid phase sintering aids in other TE materials. The effects of porosity, grain size, powder processing method, and sintering method were explored with YbAl3 and Ba0.3Co4Sb 12, with the porosity dependence of

Sb{sub 7}Te{sub 3}/ZnSb multilayer thin films for high thermal stability and long data retention phase-change memory

Energy Technology Data Exchange (ETDEWEB)

Chen, Shiyu; Wu, Weihua [Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, Shanghai 201804 (China); Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, Shanghai 201804 (China); Song, Sannian; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Science, Shanghai 200050 (China)

2017-04-15

Highlights: • Sb{sub 7}Te{sub 3} (ST) provides a fast crystallization speed, low melting temperature. • The Sb{sub 7}Te{sub 3}/ZnSb films exhibits faster crystallization speed, high thermal stability. • The calculated temperature for 10-year data retention is about 127 {sup o}C. • The Sb{sub 7}Te{sub 3}/ZnSb multilayer configuration with low power consumption. - Abstract: Phase-change memory is regard as one of the most promising candidates for the next-generation non-volatile memory. In this work, we proposed a Sb{sub 7}Te{sub 3}/ZnSb multilayer thin films to improve the thermal stability of Sb-rich Sb{sub 3}Te{sub 7}. The sheet resistance ratio between amorphous and crystalline states reached up to 4 orders of magnitude. With regard to the thermal stability, the calculated temperature for 10-year data retention is about 127 °C. The threshold current and threshold voltage of a cell based on Sb{sub 7}Te{sub 3}/ZnSb are 6.9 μA and 1.9 V, respectively. The lower RESET power is presented in the PCM cells of Sb{sub 7}Te{sub 3}/ZnSb films, benefiting from its high resistivity.

Self-diffusion in 69Ga121Sb/71Ga123Sb isotope heterostructures

Science.gov (United States)

Bracht, H.; Nicols, S. P.; Haller, E. E.; Silveira, J. P.; Briones, F.

2001-05-01

Gallium and antimony self-diffusion experiments have been performed in undoped 69Ga121Sb/71Ga123Sb isotope heterostructures at temperatures between 571 and 708 °C under Sb- and Ga-rich ambients. Ga and Sb profiles measured with secondary ion mass spectrometry reveal that Ga diffuses faster than Sb by several orders of magnitude. This strongly suggests that the two self-atom species diffuse independently on their own sublattices. Experimental results lead us to conclude that Ga and Sb diffusion are mediated by Ga vacancies and Sb interstitials, respectively, and not by the formation of a triple defect proposed earlier by Weiler and Mehrer [Philos. Mag. A 49, 309 (1984)]. The extremely slow diffusion of Sb up to the melting temperature of GaSb is proposed to be a consequence of amphoteric transformations between native point defects which suppress the formation of those native defects which control Sb diffusion. Preliminary experiments exploring the effect of Zn indiffusion at 550 °C on Ga and Sb diffusion reveal an enhanced intermixing of the Ga isotope layers compared to undoped GaSb. However, under the same conditions the diffusion of Sb was not significantly affected.

Dry etching of new phase-change material Al1.3Sb3Te in CF4/Ar plasma

International Nuclear Information System (INIS)

Zhang Xu; Rao Feng; Liu Bo; Peng Cheng; Zhou Xilin; Yao Dongning; Guo Xiaohui; Song Sannian; Wang Liangyong; Cheng Yan; Wu Liangcai; Song Zhitang; Feng Songlin

2012-01-01

The dry etching characteristic of Al 1.3 Sb 3 Te film was investigated by using a CF 4 /Ar gas mixture. The experimental control parameters were gas flow rate into the chamber, CF 4 /Ar ratio, the O 2 addition, the chamber background pressure, and the incident RF power applied to the lower electrode. The total flow rate was 50 sccm and the behavior of etch rate of Al 1.3 Sb 3 Te thin films was investigated as a function of the CF 4 /Ar ratio, the O 2 addition, the chamber background pressure, and the incident RF power. Then the parameters were optimized. The fast etch rate was up to 70.8 nm/min and a smooth surface was achieved using optimized etching parameters of CF 4 concentration of 4%, power of 300 W and pressure of 80 mTorr.

Distribution of anthropogenic fill material within the Y-12 plant area, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Sutton, G.E. Jr.; Field, S.M.

1995-10-01

Widespread groundwater contamination in the vicinity of the Oak Ridge Y-12 Plant has been documented through a variety of monitoring efforts since the late 1970s. Various contaminants, most notably volatile organic compounds (VOCs), have migrated through the subsurface and formed extensive contaminant plumes within the Knox Aquifer/Maynardville Limestone, the primary exit pathway for groundwater transport within the Bear Creek Valley. In 1991, an integrated, comprehensive effort (Upper East Fork Poplar Creek [UEFPC] Phase I monitoring network) was initiated in order to (1) identify contaminant source areas within the industrialized portions of the plant and (2) define contamination migration pathways existing between the source areas and the Knox Aquifer/Maynardville Limestone. Data obtained during previous studies have indicated that extensive zones of fill and buried utility trenches may serve as preferred migration pathways. In addition, portions of UEFPC were rerouted, with several of its tributaries being filled during the initial construction of the plant. These filled surface drainage features are also believed to serve as preferred migration pathways. The identification of preferred contaminant migration pathways within the Y-12 Plant area is essential and required to refine the current Bear Creek Valley groundwater conceptual model and to assist in the selection of technically feasible and cost effective remedial strategies. This report presents the results of an initial investigation of the occurrence of manmade (anthropogenic) fill and its effect upon groundwater movement within the plant area. These interpretations are subject to revision and improvement as further investigation of the effects of the fill upon contaminant migration progresses

DWPF simulant CPC studies for SB8

Energy Technology Data Exchange (ETDEWEB)

Koopman, D. C.; Zamecnik, J. R.

2013-06-25

The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain the Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing

DWPF simulant CPC studies for SB8

International Nuclear Information System (INIS)

Koopman, D. C.; Zamecnik, J. R.

2013-01-01

The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain the Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing

High ion conductive Sb2O5-doped β-Li3PS4 with excellent stability against Li for all-solid-state lithium batteries

Science.gov (United States)

Xie, Dongjiu; Chen, Shaojie; Zhang, Zhihua; Ren, Jie; Yao, Lili; Wu, Linbin; Yao, Xiayin; Xu, Xiaoxiong

2018-06-01

The combination of high conductivity and good stability against Li is not easy to achieve for solid electrolytes, hindering the development of high energy solid-state batteries. In this study, doped electrolytes of Li3P1-xSbxS4-2.5xO2.5x are successfully prepared via the high energy ball milling and subsequent heat treatment. Plenty of techniques like XRD, Raman, SEM, EDS and TEM are utilized to characterize the crystal structures, particle sizes, and morphologies of the glass-ceramic electrolytes. Among them, the Li3P0.98Sb0.02S3.95O0.05 (x = 0.02) exhibits the highest ionic conductivity (∼1.08 mS cm-1) at room temperature with an excellent stability against lithium. In addition, all-solid-state lithium batteries are assembled with LiCoO2 as cathode, Li10GeP2S12/Li3P0.98Sb0.02S3.95O0.05 as the bi-layer electrolyte, and lithium as anode. The constructed solid-state batteries delivers a high initial discharge capacity of 133 mAh g-1 at 0.1C in the range of 3.0-4.3 V vs. Li/Li+ at room temperature, and shows a capacity retention of 78.6% after 50 cycles. Most importantly, the all-solid-state lithium batteries with the Li10GeP2S12/Li3P0.98Sb0.02S3.95O0.05 electrolyte can be workable even at -10 °C. This study provides a promising electrolyte with the improved conductivity and stability against Li for the application of all-solid-state lithium batteries.

New uranium chalcoantimonates, RbU{sub 2}SbS{sub 8} and KU{sub 2}SbSe{sub 8}, with a polar noncentrosymmetric structure

Energy Technology Data Exchange (ETDEWEB)

Choi, K S; Kanatzidis, M G

1999-09-01

The new compounds, RbU{sub 2}SbS{sub 8} and KU{sub 2}SbSe{sub 8}, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU{sub 2}SbS{sub 8} has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U{sup 4+} atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the a-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb{sup 3+} ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb{sup +} ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU{sub 2}SbSe{sub 8} has essentially the same structure as RbU{sub 2}SbS{sub 8}. However, Sb{sup 3+} and K{sup +} ions appear disordered in every other layer resulting in a different unit cell. RbU{sub 2}SbS{sub 8} is a semiconductor with a band gap of 1.38 eV. The band gap of KU{sub 2}SbSe{sub 8} could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5--1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU{sub 2}SbS{sub 8} at 479 cm{sup {minus}1} and the diselenide stretching vibration in KU{sub 2}SbSe{sub 8} at 252 cm{sup {minus}1}. Magnetic susceptibility measurements indicate the presence of U{sup 4+} centers in the compounds. The compounds do not melt below 1,000 C under vacuum.

Device design of GaSb/CdS thin film thermal photovoltaic solar cells%基于GaSb/CdS薄膜热光伏电池的器件设计∗

Institute of Scientific and Technical Information of China (English)

吴限量; 张德贤; 蔡宏琨; 周严; 倪牮; 张建军

2015-01-01

基于GaSb薄膜热光伏器件是降低热光伏系统成本的有效途径之一，本文主要针对GaSb/CdS薄膜热光伏器件结构进行理论分析.采用AFORS-HET软件进行模拟仿真，分析GaSb和CdS两种材料各自的缺陷态密度、界面态对电池性能的影响.根据软件模拟可以得知，吸收层GaSb的缺陷态密度以及GaSb与CdS之间的界面态密度是影响电池性能的重要因素.当GaSb缺陷态增加时，主要影响电池的填充因子，电池效率明显下降.而作为窗口层的CdS缺陷态密度对电池性能影响不明显，当CdS缺陷态密度上升4个数量级时，电池效率仅下降0.11%.%Enthusiasm in the research of thermo-photovoltaic (TPV) cells has been aroused because the low bandwidth semi-conductors of III-V family are coming into use. GaSb, as a member of III-V family, has many merits such as high absorption coeffcient, and low band gap of 0.725 eV at 300 K etc.. At present thermo-photovoltaic cells are usually based on GaSb wafer, and it can be manufactured by the vertical Bridgeman method. Thermo-photovoltaic cell based on GaSb films is one of the effective ways to reduce the cost of the thermo-photovoltaic system. GaSb polycrystalline films can be grown by physical vapor deposition (PVD) which has advantages in using fewer materials and energy, and also in doing little harm to the environment. Because of residual acceptor defects VGaGaSb, GaSb thin film is usually of p-type semiconductor. So we should find n-type semiconductor material to form pn junction. We choose CdS as the emission layer of a cell structure. CdS belongs to n-type semiconductor with a narrow band gap of 2.4 eV and high light transmissivity. CdS thin film grown by chemical bath deposition (CBD) has passivation properties for GaSb. CdS layers can remove native oxides from GaSb surface and reduce the surface recombination velocity of GaSb. This paper focuses on theoretical analysis of GaSb/CdS thin film photovoltaic

CHARACTERIZATION OF VITRIFIED SAVANNAH RIVER SITE SB4 WASTE SURROGATE PRODUCED IN COLD CRUCIBLE

International Nuclear Information System (INIS)

Marra, J

2008-01-01

Savannah River Site (SRS) sludge batch 4 (SB4) waste surrogate with high aluminum and iron content was vitrified with commercially available Frit 503-R4 (8 wt.% Li 2 O, 16 wt.% B2O3, 76 wt.% SiO 2 ) by cold crucible inductive melting using lab- (56 mm inner diameter), bench- (236 mm) and large-scale (418 mm) cold crucible. The waste loading ranged between 40 and 60 wt.%. The vitrified products obtained in the lab-scale cold crucible were nearly amorphous with traces of unreacted quartz in the product with 40 wt.% waste loading and traces of spinel phase in the product with 50 wt.% waste loading. The glassy products obtained in the bench-scale cold crucible are composed of major vitreous and minor iron-rich spinel phase whose content at ∼60 wt.% waste loading may achieve ∼10 vol.%. The vitrified waste obtained in the large-scale cold crucible was also composed of major vitreous and minor spinel structure phases. No nepheline phase has been found. Average degree of crystallinity was estimated to be ∼12 vol.%. Anionic motif of the glass network is built from rather short metasilicate chains and boron-oxygen constituent based on boron-oxygen triangular units

The Quantum Chemistry Calculation and Thermoelectrics of Bi-Sb-Te Series

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

The density function theory and discrete variation method(DFT-DVM) was used to study correlation between composition, structure, chemical bond,and property of thermoelectrics of Bi-Sb-Te series.8 models of Bi20-xSbxTe32(x=0,2,6,8,12,14,18 and 20) were calculated.The results show that there is less difference in the ionic bonds between Te(Ⅰ)-Bi(Sb) and Te(Ⅱ)-Bi(Sb), but the covalent bond of Te(Ⅰ)-Bi(Sb) is stronger than that of Te(Ⅱ)-Bi(Sb).The interaction between Te(Ⅰ) and Te(Ⅰ) in different layers is the weakest and the interaction should be Van Der Waals power.The charge of Sb is lower than that of Bi,and the ionic bond of Te-Sb is weaker than that of Te-Bi.The covalent bond of Te-Sb is also weaker than that of Te-Bi.Therefore,the thermoelectric property may be improved by adjusting the electrical conductivity and thermal conductivity through changing the composition in the compounds of Bi-Sb-Te. The calculated results are consistent with the experiments.

Evaluation of the novel 5-HT4 receptor PET ligand [11C]SB207145 in the Göttingen minipig

DEFF Research Database (Denmark)

Kornum, Birgitte R; Lind, Nanna M; Gillings, Nic

2009-01-01

This study investigates 5-hydroxytryptamine 4 (5-HT(4)) receptor binding in the minipig brain with positron emission tomography (PET), tissue homogenate-binding assays, and autoradiography in vitro. The cerebral uptake and binding of the novel 5-HT(4) receptor radioligand [(11)C]SB207145 in vivo...... was modelled and the outcome compared with postmortem receptor binding. Different models for quantification of [(11)C]SB207145 binding were evaluated: One-tissue and two-tissue compartment kinetic modelling, Logan arterial input, and three different reference tissue models. We report that the pig...... model provides stable and precise estimates of the binding potential in all regions. The binding potentials calculated for striatum, midbrain, and cortex from the PET data were highly correlated with 5-HT(4) receptor concentrations determined in brain homogenates from the same regions, except...

Enhancement in CO2 Adsorption Capacity and Selectivity in the Chalcogenide Aerogel CuSb2S4 by Post-synthetic Modification with LiCl

KAUST Repository

Ahmed, Ejaz; Rothenberger, Alexander

2015-01-01

The new chalcogel CuSb2S4 was obtained by reacting Cu(OAc)2·H2O with KSbS2 in a water/formamide mixture at room temperature. In order to modify the gas adsorption capacity the synthesized CuSb2S4 aerogel was loaded with different amounts of LiCl. CO

SB265610 is an allosteric, inverse agonist at the human CXCR2 receptor

Science.gov (United States)

Bradley, ME; Bond, ME; Manini, J; Brown, Z; Charlton, SJ

2009-01-01

Background and purpose: In several previous studies, the C-X-C chemokine receptor (CXCR)2 antagonist 1-(2-bromo-phenyl)-3-(7-cyano-3H-benzotriazol-4-yl)-urea (SB265610) has been described as binding competitively with the endogenous agonist. This is in contrast to many other chemokine receptor antagonists, where the mechanism of antagonism has been described as allosteric. Experimental approach: To determine whether it displays a unique mechanism among the chemokine receptor antagonists, the mode of action of SB265610 was investigated at the CXCR2 receptor using radioligand and [35S]-GTPγS binding approaches in addition to chemotaxis of human neutrophils. Key results: In equilibrium saturation binding studies, SB265610 depressed the maximal binding of [125I]-interleukin-8 ([125I]-IL-8) without affecting the Kd. In contrast, IL-8 was unable to prevent binding of [3H]-SB265610. Kinetic binding experiments demonstrated that this was not an artefact of irreversible or slowly reversible binding. In functional experiments, SB265610 caused a rightward shift of the concentration-response curves to IL-8 and growth-related oncogene α, but also a reduction in maximal response elicited by each agonist. Fitting these data to an operational allosteric ternary complex model suggested that, once bound, SB265610 completely blocks receptor activation. SB265610 also inhibited basal [35S]-GTPγS binding in this preparation. Conclusions and implications: Taken together, these data suggest that SB265610 behaves as an allosteric inverse agonist at the CXCR2 receptor, binding at a region distinct from the agonist binding site to prevent receptor activation, possibly by interfering with G protein coupling. PMID:19422399

Self-diffusion in 69Ga121Sb/71Ga123Sb isotope heterostructures

OpenAIRE

Bracht, H.; Nicols, S. P.; Haller, E. E.; Silveira, Juan Pedro; Briones Fernández-Pola, Fernando

2001-01-01

Gallium and antimony self-diffusion experiments have been performed in undoped 69Ga121Sb/71Ga123Sb isotope heterostructures at temperatures between 571 and 708 °C under Sb- and Ga-rich ambients. Ga and Sb profiles measured with secondary ion mass spectrometry reveal that Ga diffuses faster than Sb by several orders of magnitude. This strongly suggests that the two self-atom species diffuse independently on their own sublattices. Experimental results lead us to conclude that Ga and Sb diffusio...

Laser induced photoluminescence from Ge{sub 28}Se{sub 60}Sb{sub 12} chalcogenide nano colloids

Energy Technology Data Exchange (ETDEWEB)

Tintu, R., E-mail: tintu_tillanivas@yahoo.co.in [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam-686560 (India); Nampoori, V.P.N.; Radhakrishnan, P.; Thomas, Sheenu [International School of Photonics, Cochin University of Science and Technology, Cochin 689110 (India); Unnikrishnan, N.V. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam-686560 (India)

2013-04-01

We report the observation of two-photon induced photoluminescence from Ge{sub 28}Se{sub 60}Sb{sub 12} nano colloid solutions using frequency doubled Nd:YAG laser. Quadratic emission intensity dependence verifies the two photon absorption for the observed luminescence at an excitation of 532 nm. The optical band gap of the material is found to be tunable depending on the cluster size of the nano colloids. The cluster formation and the dependence of the cluster size with concentration were confirmed by the SEM analysis. Confocal imaging was done to confirm the emission from the clusters in the nano colloid solutions.

Residual carrier density in GaSb grown on Si substrates

International Nuclear Information System (INIS)

Akahane, Kouichi; Yamamoto, Naokatsu; Gozu, Shin-ichiro; Ueta, Akio; Ohtani, Naoki

2006-01-01

The relationships between the densities of residual carriers and those of dislocation in GaSb films grown on Si substrates were investigated. Dislocation density was evaluated by cross-sectional transmission electron microscopy (TEM). The TEM images indicated that the dislocation density after a 5-μm-thick GaSb film was grown was below 1 x 10 8 /cm 2 although the density near the interface between the Si substrate and the GaSb film was about 3 x 10 9 /cm 2 . Forming a dislocation loop by growing a thick GaSb layer may decrease the dislocation density. The density and mobility of the residual carrier were investigated by Hall measurement using the van der Pauw method. The residual carriers in GaSb grown on Si substrates were holes, and their densities decreased significantly from 4.2 x 10 18 to 1.4 x 10 17 /cm 3 as GaSb thickness was increased from 500 to 5500 nm

Magnetocaloric effect of Gd4(BixSb1-x)3 alloy series

International Nuclear Information System (INIS)

Niu, Xuejun

1999-01-01

Alloys from the Gd 4 (Bi x Sb 1-x ) 3 series were prepared by melting a stoichiometric amounts of pure metals in an induction furnace. The crystal structure is of the anti-Th 3 P 4 type (space group Ibar 43d) for all the compounds tested. The linear increase of the lattice parameters with Bi concentration is attributed to the larger atomic radius of Bi than that of Sb. Magnetic measurements show that the alloys order ferromagnetically from 266K to 330K, with the ordering temperature increasing with decreasing Bi concentration. The alloys are soft ferromagnets below their Curie temperatures, and follow the Curie-Weiss law above their ordering temperatures. The paramagnetic effective magnetic moments are low compared to the theoretical value for a free Gd 3+ , while the ordered magnetic moments are close to the theoretical value for Gd. The alloys exhibit a moderate magnetocaloric effect (MCE) whose maxima are located between 270K and 338K and have relatively wide peaks. The peak MCE temperature decreases with decreasing Bi concentration while the peak height increases with decreasing Bi concentration. The Curie temperatures determined from inflection points of heat capacity are in good agreement with those obtained from the magnetocaloric effect. The MCE results obtained from the two different methods (magnetization and heat capacity) agree quite well with each other for all of the alloys in the series

Oral administration of the 5-HT6 receptor antagonists SB-357134 and SB-399885 improves memory formation in an autoshaping learning task.

Science.gov (United States)

Perez-García, Georgina; Meneses, Alfredo

2005-07-01

In this work we aimed to re-examine the 5-HT6 receptor role, by testing the selective antagonists SB-357134 (1-30 mg/kg p.o.) and SB-399885 (1-30 mg/kg p.o.) during memory consolidation of conditioned responses (CR%), in an autoshaping Pavlovian/instrumental learning task. Bioavailability, half-life and minimum effective dose to induce inappetence for SB-357134 were 65%, 3.4 h, and 30 mg/kg p.o., and for SB-399885 were 52%, 2.2 h, and 50 mg/kg p.o., respectively. Oral acute and chronic administration of either SB-357134 or SB-399885 improved memory consolidation compared to control groups. Acute administration of SB-357134, at 1, 3, 10 and 30 mg/kg, produced a CR% inverted-U curve, eliciting the latter dose a 7-fold increase relative to saline group. Acute injection of SB-399885 produced significant CR% increments, being 1 mg/kg the most effective dose. Repeated administration (7 days) of either SB-357134 (10 mg/kg) or SB-399885 (1 mg/kg) elicited the most significant CR% increments. Moreover, modeling the potential therapeutic benefits of 5-HT6 receptor blockade, acute or repeated administration of SB-399885, at 10 mg/kg reversed memory deficits produced by scopolamine or dizocilpine, and SB-357134 (3 and 10 mg/kg) prevented amnesia and even improved performance. These data support the notion that endogenously 5-HT acting, via 5-HT6 receptor, improves memory consolidation.

Ferro electrical properties of GeSbTe thin films; Propiedades ferroelectricas de peliculas delgadas de GeSbTe

Energy Technology Data Exchange (ETDEWEB)

Gervacio A, J. J.; Prokhorov, E.; Espinoza B, F. J., E-mail: jgervacio@qro.cinvestav.m [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Juriquilla, 76230 Queretaro (Mexico)

2011-07-01

The aim of this work is to investigate and compare ferro electrical properties of thin GeSbTe films with composition Ge{sub 4}Sb{sub 1}Te{sub 5} (with well defined ferro electrical properties) and Ge{sub 2}Sb{sub 2}Te{sub 5} using impedance, optical reflection, XRD, DSc and Piezo response Force Microscopy techniques. The temperature dependence of the capacitance in both materials shows an abrupt change at the temperature corresponding to ferroelectric-paraelectric transition and the Curie-Weiss dependence. In Ge{sub 2}Sb{sub 2}Te{sub 5} films this transition corresponds to the end from a NaCl-type to a hexagonal transformation. Piezo response Force Microscopy measurements found ferroelectric domains with dimension approximately equal to the dimension of grains. (Author)

Tšaikovski, P. La Fille des neiges (musique de scene op. 12) / Serge Martin

Index Scriptorium Estoniae

Martin, Serge

1995-01-01

Uuest heliplaadist "Tšaikovski, P. La Fille des neiges (musique de scene op. 12). University Musical Society Choral Union. Detroit Symphony Orchestra, Neeme Järvi. Chandos CHAN 9324, distribution Media 7 (CD: 157 F). 1994. TT: 1h 19'04"

Compositional and structural characterisation of GaSb and GaInSb

International Nuclear Information System (INIS)

Corregidor, V.; Alves, E.; Alves, L.C.; Barradas, N.P.; Duffar, Th.; Franco, N.; Marques, C.; Mitric, A.

2005-01-01

Low band gap III-V semiconductors are researched for applications in thermophotovoltaic technology. GaSb crystal is often used as a substrate. Ga 1-x In x Sb is also a promising substrate material, because its lattice parameters can be adjusted by controlling x. We used a new method to synthesise GaSb and GaInSb, in which a high frequency alternate magnetic field is used to heat, to melt and to mix the elements. We present a compositional and structural characterisation of the materials using a combination of complementary techniques. Rutherford backscattering was used to determine accurately the composition of the GaSb. With proton induced X-ray emission in conjunction with a 3 x 3 μm 2 micro-beam we studied the homogeneity of the samples. Structural analysis and phase identification were done with X-ray diffraction. The results for GaSb show a homogeneous composition while the GaInSb samples were found to be strongly heterogeneous at the end of the ingot. The ingots produced are competitive feed material, when compared to other growth techniques, to be used in a second step for the production of good quality ternary crystals

Defect Structure of High-Temperature-Grown GaMnSb/GaSb

International Nuclear Information System (INIS)

Romanowski, P.; Bak-Misiuk, J.; Dynowska, E.; Domagala, J.Z.; Wojciechowski, T.; Jakiela, R.; Sadowski, J.; Barcz, A.; Caliebe, W.

2010-01-01

GaMnSb/GaSb(100) layers with embedded MnSb inclusions have been grown at 720 K using MBE technique. This paper presents the investigation of the defect structure of Ga1-xMnxSb layers with different content of manganese (up to x = 0.07). X-ray diffraction method using conventional and synchrotron radiation was applied. Dimensions and shapes of inclusions were detected by scanning electron microscopy. Depth profiles of elements were measured using secondary ion mass spectroscopy technique. (authors)

Sb interactions with TaC precipitates and Cu in ion-implanted α-Fe

International Nuclear Information System (INIS)

Follstaedt, D.M.; Myers, S.M.

1980-01-01

The interactions of Sb with the other species implanted into Fe to form Fe-Ta-C-Sb and Fe-Cu-Sb alloys have been examined with transmission electron microscopy and Rutherford backscattering following annealing at 873 0 K. Trapping of Sb at TaC precipitates is observed in the former alloy just as was previously observed in Fe-Ti-C-Sb. In Fe-Cu-Sb, Sb interactions are governed by the atomic ratio of Sb to Cu. For ratios between 0.2 to 0.4, the compound β-Cu 3 Sb was observed to form. For Sb to Cu ratios approx.< 0.1, fcc Cu precipitates were observed. In addition to the expected Sb dissolution in Cu, Sb trapping by Cu precipitates is also observed. The binding enthalpy of Sb at both TaC and Cu precipitates with respect to a solution site in the bcc Fe is the same as observed for TiC, approx. 0.4 eV. The constancy of the binding enthalpy at such chemically dissimilar precipitates supports the hypothesis that the trapping is due to the structural discontinuity of the precipitate-host interface. The observed Sb trapping at precipitates is of potential significance for the control of temper embrittlement in bcc steels

DWPF Simulant CPC Studies For SB8

Energy Technology Data Exchange (ETDEWEB)

Newell, J. D.

2013-09-25

Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51 heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected

Ab Initio Molecular Dynamics Studies of Pb m Sb n ( m + n ≤ 9) Alloy Clusters

Science.gov (United States)

Song, Bingyi; Xu, Baoqiang; Yang, Bin; Jiang, Wenlong; Chen, Xiumin; Xu, Na; Liu, Dachun; Dai, Yongnian

2017-10-01

Structure, stability, and dynamics of Pb m Sb n ( m + n ≤ 9) clusters were investigated using ab initio molecular dynamics. Size dependence of binding energies, the second-order energy difference of clusters, dissociation energy, HOMO-LUMO gaps, Mayer bond order, and the diffusion coefficient of Pb m Sb n clusters were discussed. Results suggest that Pb3Sb2, Pb4Sb2, and Pb5Sb4 ( n = 2 or 4) clusters have higher stability than other clusters, which is consistent with previous findings. In case of Pb-Sb alloy, the dynamics results show that Pb4Sb2 (Pb-22.71 wt pct Sb) can exist in gas phase at 1073 K (800 °C), which reasonably explains the azeotropic phenomenon, and the calculated values are in agreement with the experimental results (Pb-22 wt pct Sb).

Computational studies of novel thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Singh, D J; Mazin, I I; Kim, S G; Nordstrom, L

1997-07-01

The thermoelectric properties of La-filled skutterdites and {beta}-Zn{sub 4}Sb{sub 3} are discussed from the point of view of their electronic structures. These are calculated from first principles within the local density approximation. The electronic structures are in turn used to determine transport related quantities, {beta}-Zn{sub 4}Sb{sub 3} is found to be metallic with a complex Fermi surface topology, which yields a non-trivial dependence of the Hall concentration on the band filling. Calculations of the variation with band filling are used to extract the carrier concentration from the experimental Hall number. At this band filling, which corresponds to 0.1 electrons per 22 atom unit cell, the authors calculate a Seebeck coefficient and temperature dependence in good agreement with the experimental value. The high Seebeck coefficients in a metallic material are remarkable, and arise because of the strong energy dependence of the Fermiology near the experimental band filling. Virtual crystal calculations for La(Fe,Co){sub 4}Sb{sub 12}. The valence band maximum occurs at the {Gamma} point and is due to a singly degenerate dispersive (Fe,Co)-Sb band, which by itself would not be favorable for TE. However, very flat transition metal derived bands occur in close proximity and become active as the doping level is increased, giving a non-trivial dependence of the properties on carrier concentration and explaining the favorable TE properties.

Structural, electric and kinetic parameters of ternary alloys of GeSbTe

Energy Technology Data Exchange (ETDEWEB)

Morales-Sanchez, E. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico)]. E-mail: m6007@ciateq.net.mx; Prokhorov, E.F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico); Gonzalez-Hernandez, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico); Mendoza-Galvan, A. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico)

2005-01-03

Thin amorphous films of GeSbTe have been widely employed in the technology used for phase change optical memory or compact disks. In this article, we report on measurements of resistance, transmittance, and X-ray diffraction in thin films with stoichiometric compositions of Ge{sub 1}Sb{sub 4}Te{sub 7}, Ge{sub 1}Sb{sub 2}Te{sub 4}, Ge{sub 2}Sb{sub 2}Te{sub 5}, and Ge{sub 4}Sb{sub 1}Te{sub 5.} The resistivity, lattice constant, and the temperature at which transformation from the amorphous phase to the cubic crystalline structure occurs were calculated for each stoichiometric composition, and the energy activation was determined, applying Kissinger's model. It was found that the Ge{sub 4}Sb{sub 1}Te{sub 5} composition has the highest crystallization temperature (425 K), the highest resistivity (0.178 {omega} cm), the greatest E{sub a} (3.09 eV), and the lowest lattice constant (a=5.975 A) in the cubic phase at 170 deg C.

Variation of the refractive index for the active layer of the double heterostructure GaAlAsSb/GaInAsSb/GaAlAsSb in injected mode

International Nuclear Information System (INIS)

Mohou, M.A.

1995-01-01

This work reports on the influence of the injected current on the refractive index in the active layer of GaInAsSb/GaAlAsSb laser diodes. These diodes present at threshold a full beam width at half power θ perpendicular of about 52 deg. C. The fluctuation of the refractive index caused by the injection of free carriers was studied on the basis of the evolution of θ perpendicular as a function of the injected current. It was shown that the inversion of the population which follows the rising of the gain, causes a slight decrease of the refractive index. 12 refs, 5 figs

The crystal structure of franckeite, Pb21.7Sn9.3Fe4.0Sb8.1S56.9

DEFF Research Database (Denmark)

Makovicky, Emil; Petricek, Vaclav; Dusek, Michal

2011-01-01

and forms a homologous pair with cylindrite, which has thinner Q slabs. The Q slabs in franckeite are four atomic layers thick. The two components have their own lattices and a common modulation. The Q slab of the refined franckeite structure, Pb21.74Sn9.34Fe3.95Sb8.08S56.87, is an MS layer (M = Pb2+, Sn2...... layer (M = Sn4+, Fe2+) with a = 3.665(8), b = 6.2575(16), c = 17.419(5) Å, a = 95.25(2)°, ß = 95.45(2)°, ¿ = 89.97(2)°; the modulation vector is q = –0.00087(8) a* + 0.13725(16) b* – 0.0314(4) c*. The a and b vectors of both subsystems are parallel; the c vectors diverge. (3+2)D superspace refinement...... was refined as Pb0.74(Sn,Sb)0.26, whereas that of cations, which are adjacent to the interspace with lone electron pairs, with a configuration analogous to that observed in orthorhombic SnS, corresponds to (Sn,Sb)0.73Pb0.27. Iron is dispersed over the octahedral Sn4+ sites in the H layer. Transversal...

Analysis of the FIST integral tests 4DBA1, 6SB2C and T1QUV with TRAC-BFl/v2001.2

International Nuclear Information System (INIS)

Analytis, G.Th.

2004-01-01

As part of the assessment of the frozen version of the PSU TRAC-BFl/v2001.2 and its qualification as a LB-LOCA and SB-LOCA code, in this work, we shall outline the comparisons between measurements and code predictions for three FIST tests: The LB-LOCA test 4DBA1, the SB-LOCA test 6SB2C and the failure to maintain water level test T1QUV. We shall study the effect of the number of axial levels in the active core as well as (in the case of the SB-LOCA test 6SB2C) the effect of the timing of the activation of the reflooding options/heat transfer package on the code predictions. Furthermore, we shall show that by using the upwinding option of some terms of the three-dimensional momentum equations, severe mass-error problems appearing in the analysis of the test T1QUV can be resolved. Generally, we shall show that although there are some differences between measurements and predictions, TRAC-BF1 captures quite well the overall behaviour of the LB-LOCA transient (depending on the number of axial nodes in the core) but underpredicts the rod surface temperatures of the SB-LOCA test 6SB2C

Investigation of structural and electrochemical properties of LaSrCo{sub 1−x}Sb{sub x}O{sub 4} (0≤x≤0.20) as potential cathode materials in intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Wang, Junkai; Zhou, Jun, E-mail: zhoujun@mail.xjtu.edu.cn; Fan, Weiwei; Wang, Wendong; Wu, Kai; Cheng, Yonghong

2017-03-15

The structural and electrochemical properties of the layered perovskite oxides LaSrCo{sub 1−x}Sb{sub x}O{sub 4} (0≤x≤0.20) were investigated to study the effects of substituting Sb for Co for application as cathode materials in intermediate temperature solid oxide fuel cells (IT-SOFCs). The results of crystal structure analyses show the maximum content of Sb in LaSrCo{sub 1−x}Sb{sub x}O{sub 4} to be 0.05 as a pure single phase. XPS shows that Co and Sb in LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} may possess mixed-oxidation states. The electrical conductivity increased greatly after Sb substitution. An improvement in the cathode polarization (R{sub p}) values is observed from the Sb-doped sample with respect to the undoped samples. For example, R{sub p} of LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} on LSGM was observed to be 0.16 Ω cm{sup 2} at 800 °C in air. The main rate-limiting step for LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} cathode is charge transfer of oxygen atoms. These results indicate that Sb can be incorporated into LaSrCo{sub 1−x}Sb{sub x}O{sub 4} based materials and can have a beneficial effect on the performance, making them potentially suitable for use as cathode materials in IT-SOFCs. - Graphical abstract: The oxygen partial pressure dependence of polarization resistances for a new layered perovskite cathode LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} at various temperatures was measured. - Highlights: • The maximum content of Sb was 0.05 mol in LaSrCo{sub 1−x}Sb{sub x}O{sub 4}. • The maximum electrical conductivity is 194 S cm{sup −1}for LaSrCo{sub 0.95}Sb{sub 0.05}O{sub 4} at 800 °C. • A rate-limiting process of charge transfer presented.

GaSb solar cells grown on GaAs via interfacial misfit arrays for use in the III-Sb multi-junction cell

Science.gov (United States)

Nelson, George T.; Juang, Bor-Chau; Slocum, Michael A.; Bittner, Zachary S.; Laghumavarapu, Ramesh B.; Huffaker, Diana L.; Hubbard, Seth M.

2017-12-01

Growth of GaSb with low threading dislocation density directly on GaAs may be possible with the strategic strain relaxation of interfacial misfit arrays. This creates an opportunity for a multi-junction solar cell with access to a wide range of well-developed direct bandgap materials. Multi-junction cells with a single layer of GaSb/GaAs interfacial misfit arrays could achieve higher efficiency than state-of-the-art inverted metamorphic multi-junction cells while forgoing the need for costly compositionally graded buffer layers. To develop this technology, GaSb single junction cells were grown via molecular beam epitaxy on both GaSb and GaAs substrates to compare homoepitaxial and heteroepitaxial GaSb device results. The GaSb-on-GaSb cell had an AM1.5g efficiency of 5.5% and a 44-sun AM1.5d efficiency of 8.9%. The GaSb-on-GaAs cell was 1.0% efficient under AM1.5g and 4.5% at 44 suns. The lower performance of the heteroepitaxial cell was due to low minority carrier Shockley-Read-Hall lifetimes and bulk shunting caused by defects related to the mismatched growth. A physics-based device simulator was used to create an inverted triple-junction GaInP/GaAs/GaSb model. The model predicted that, with current GaSb-on-GaAs material quality, the not-current-matched, proof-of-concept cell would provide 0.5% absolute efficiency gain over a tandem GaInP/GaAs cell at 1 sun and 2.5% gain at 44 suns, indicating that the effectiveness of the GaSb junction was a function of concentration.

Experimental determination of the energy levels of the antimony atom (Sb II), ions of the antimony (Sb II, Sb III), mercury (Hg IV) and cesium (Cs X)

International Nuclear Information System (INIS)

Arcimowicz, B.

1993-01-01

The thesis concerns establishing the energy scheme of the electronic levels, obtained from the analysis of the investigated spectra of antimony atom and ions (Sb I, Sb II, Sb III) and higher ionized mercury (Hg IV) and cesium (Cs X) atoms. The experimental studies were performed with optical spectroscopy methods. The spectra of the elements under study obtained in the spectral range from visible (680 nm) to vacuum UV (40 nm) were analysed. The classification and spectroscopic designation of the experimentally established 169 energy levels were obtained on the basis of the performed calculations and the fine structure analysis. The following configurations were considered: 5s 2 5p 2 ns, 5s 2 5p 2 n'd, 5s5p 4 of the antimony atom, 5s 2 5pns, 5s 2 5pn'd, 5s5p 3 of the ion Sb II, 5s 2 ns, 5s 2 n'd, 5s5p 2 of the on Sb III, 5d 8 6p of the ion Hg IV 4d 9 5s and 4d 9 5p Cs X. A reclassification was performed and some changes were introduced to the existing energy level scheme of the antimony atom, with the use of the information obtained from the absorption spectrum taken in the VUV region by the ''flash pyrolysis'' technique. The measurements of the hyperfine splittings in 19 spectral lines belonging to the antimony atom and ions additionally confirmed the assumed classification of the levels involved in these lines. The energy level scheme, obtained for Sb III, was compared to the other ones in the isoelectronic sequence starting with In I. On the basis of the analysis of the Hg IV spectrum it was proved that ground configuration of the three times ionized mercury atom is 5d 9 not 5d 8 6s as assumed until now. The fine structure, established from the analysis of the spectra of the elements under study was examined in multiconfiguration approximation. As a result of the performed calculations the fine structure parameters and wavefunctions were determined for the levels whose energy values were experimentally established in the thesis. (author). 140 refs, 22 figs, 17