1
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Hasegawa T, Inui M, Onimaru T, Kajihara Y, Hosokawa S, Nakajima Y, Matsuda K, Takabatake T, Hiroi S, Uchiyama H, Tsutsui S. Phonon dispersion curves in the type-I crystalline and molten clathrate compound Eu 8Ga 16Ge 30. J Phys Condens Matter 2023; 35:114002. [PMID: 36603227 DOI: 10.1088/1361-648x/acb0a5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
The dynamic structure factorS(Q,E), whereQandEare momentum and energy transfer, respectively, has been measured for liquid Eu8Ga16Ge30(EGG), using inelastic x-ray scattering. The excitation energy of the longitudinal acoustic mode in the liquid was scaled to that in liquid Ba8Ga16Sn30(BGS) with the effective mass. This result means that the local structure in both liquids are similar. The longitudinal acoustic excitation energy of type-I clathrate compound EGG disperses faster than that in the liquid, suggesting that the interatomic force is weakened on melting. The lower energy excitation was observed in both liquid EGG and liquid BGS. In comparison with the longitudinal phonon dispersion in crystalline clathrate compound EGG obtained by density functional theory-based calculations, the lower energy in the liquid was found to be near the optical mode energy. The result indicates that the lower energy mode arises from the relative motion between Eu and (Ga, Ge) atoms.
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Affiliation(s)
- Takumi Hasegawa
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Masanori Inui
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Takahiro Onimaru
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Yukio Kajihara
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Shinya Hosokawa
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Yoichi Nakajima
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Kazuhiro Matsuda
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshiro Takabatake
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Satoshi Hiroi
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo-cho, Hyogo 679-5198, Japan
| | - Hiroshi Uchiyama
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo-cho, Hyogo 679-5198, Japan
| | - Satoshi Tsutsui
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo-cho, Hyogo 679-5198, Japan
- Institute of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, Hitachi, Ibaraki 316-8511, Japan
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2
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Shimizu Y, Suekuni K, Saito H, Lemoine P, Guilmeau E, Raveau B, Chetty R, Ohta M, Takabatake T, Ohtaki M. Synergistic Effect of Chemical Substitution and Insertion on the Thermoelectric Performance of Cu 26V 2Ge 6S 32 Colusite. Inorg Chem 2021; 60:11364-11373. [PMID: 34269565 DOI: 10.1021/acs.inorgchem.1c01321] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Copper-based sulfides are promising materials for thermoelectric applications, which can convert waste heat into electricity. This study reports the enhanced thermoelectric performance of Cu26V2Ge6S32 colusite via substitution of antimony (Sb) for germanium (Ge) and introduction of copper (Cu) as an interstitial atom. The crystal structure of the solid solutions and Cu-rich compounds were analyzed by powder X-ray diffraction and scanning transmission electron microscopy. Both chemical approaches decrease the hole carrier concentration, which leads to a reduction in the electronic thermal conductivity while keeping the thermoelectric power factor at a high value. Furthermore, the interstitial Cu atoms act as phonon scatterers, thereby decreasing the lattice thermal conductivity. The combined effects increase the dimensionless thermoelectric figure of merit ZT from 0.3 (Cu26V2Ge6S32) to 0.8 (Cu29V2Ge5SbS32) at 673 K.
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Affiliation(s)
- Yuta Shimizu
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Koichiro Suekuni
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan.,Transdisciplinary Research and Education Center for Green Technologies, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Hikaru Saito
- Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Pierric Lemoine
- Université de Rennes 1, CNRS, ISCR-UMR 6226, F-35000 Rennes, France
| | - Emmanuel Guilmeau
- CRISMAT, CNRS, Normandie Université, ENSICAEN, UNICAEN, 14000 Caen, France
| | - Bernard Raveau
- CRISMAT, CNRS, Normandie Université, ENSICAEN, UNICAEN, 14000 Caen, France
| | - Raju Chetty
- Global Zero Emission Research Center (GZR), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8569, Japan
| | - Michihiro Ohta
- Global Zero Emission Research Center (GZR), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8569, Japan
| | - Toshiro Takabatake
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Michitaka Ohtaki
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan.,Transdisciplinary Research and Education Center for Green Technologies, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
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3
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Shimura Y, Wörl A, Sundermann M, Tsuda S, Adroja DT, Bhattacharyya A, Strydom AM, Hillier AD, Pratt FL, Gloskovskii A, Severing A, Onimaru T, Gegenwart P, Takabatake T. Antiferromagnetic Correlations in Strongly Valence Fluctuating CeIrSn. Phys Rev Lett 2021; 126:217202. [PMID: 34114835 DOI: 10.1103/physrevlett.126.217202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
CeIrSn with a quasikagome Ce lattice in the hexagonal basal plane is a strongly valence fluctuating compound, as we confirm by hard x-ray photoelectron spectroscopy and inelastic neutron scattering, with a high Kondo temperature of T_{K}∼480 K. We report a negative in-plane thermal expansion α/T below 2 K, which passes through a broad minimum near 0.75 K. Volume and a-axis magnetostriction for B∥a are markedly negative at low fields and change sign before a sharp metamagnetic anomaly at 6 T. These behaviors are unexpected for Ce-based intermediate valence systems, which should feature positive expansivity. Rather they point towards antiferromagnetic correlations at very low temperatures. This is supported by muon spin relaxation measurements down to 0.1 K, which provide microscopic evidence for a broad distribution of internal magnetic fields. Comparison with isostructural CeRhSn suggests that these antiferromagnetic correlations emerging at T≪T_{K} result from geometrical frustration.
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Affiliation(s)
- Y Shimura
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - A Wörl
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - M Sundermann
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - S Tsuda
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - D T Adroja
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
| | - A Bhattacharyya
- Department of Physics, Ramakrishna Mission Vivekananda Educational and Research Institute, Belur Math, Howrah 711202, West Bengal, India
| | - A M Strydom
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
| | - A D Hillier
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
| | - F L Pratt
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
| | - A Gloskovskii
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - A Severing
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany
| | - T Onimaru
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - P Gegenwart
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - T Takabatake
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
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4
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Ritter C, Adroja DT, Le MD, Muro Y, Takabatake T. Magnetic structure and crystal field excitations of NdOs 2Al 10: a neutron scattering study. J Phys Condens Matter 2021; 33:185802. [PMID: 33711836 DOI: 10.1088/1361-648x/abee3b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
We have investigated the magnetic properties of a polycrystalline sample of NdOs2Al10using neutron diffraction and inelastic neutron scattering, magnetic susceptibility and heat capacity measurements. The magnetic susceptibility data reveal an antiferromagnetic transition atTN1= 2.2 K while the heat capacity data which extend to lower temperatures show a further transition atTN2= 1.1 K. The INS measurements detect four well-resolved crystal field excitations at 7.4, 12.4, 17.6 meV and 19.2 meV at 5 K. The positions and intensities of the observed CEF excitations and the temperature dependence of previously published single crystal susceptibility data are analysed based on the orthorhombic CEF model of theJ= 9/2 ground state multiplet of Nd3+ion. The neutron diffraction study reveals the magnetic structure atT= 1.6 K to be of sine wave type (κ= [0, 0.723, 0]) with an ordered state moment ofμNd3+= 1.59(1)μBaligned along thea-axis in agreement with the single ion crystal field anisotropy. This indicates that the magnetism of NdOs2Al10is governed by the RKKY interactions in agreement with otherRT2Al10(R= Nd, Sm, Tb,T= Fe, Ru and Os), but different to that ofR= Ce based compounds where anisotropic two ions interaction as well as Kondo interaction govern the anomalous direction of the ordered state moment.
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Affiliation(s)
- C Ritter
- Institut Laue-Langevin, 71 avenue des Martyrs, F-38042 Grenoble Cedex 9, France
| | - D T Adroja
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon, OX11 0QX, United Kingdom
- Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
| | - M D Le
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon, OX11 0QX, United Kingdom
| | - Y Muro
- Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan
| | - T Takabatake
- Quantum Matter Program, Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
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5
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Sato H, Nagasaki T, Suekuni K, Tanaka HI, Rousuli A, Nakamura S, Kawamura N, Zheng XG, Fujii T, Takabatake T. Cu 2p-1s x-ray emission spectroscopy of mineral tetrahedrite Cu12Sb4S13. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2019.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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6
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Onimaru T, Inoue YF, Ishida A, Umeo K, Oohara Y, Sato TJ, Adroja DT, Takabatake T. Sinusoidally modulated magnetic structure of Kramers local moments in CePd 5Al 2. J Phys Condens Matter 2019; 31:125603. [PMID: 30641513 DOI: 10.1088/1361-648x/aafe51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The crystalline electric field (CEF) level scheme and magnetic structure of a tetragonal antiferromagnet CePd5Al2 with [Formula: see text] K and [Formula: see text] K were studied by neutron scattering, magnetization and magnetoresistance measurements. Inelastic neutron scattering measurements on the powder sample revealed CEF excitations at 21.3 and 22.4 meV. The derived wave functions of the CEF ground state for the Ce3+ ion consist primarily of [Formula: see text] under the tetragonal symmetry. By means of single-crystal neutron diffraction, magnetic Bragg peaks characterized by a propagation vector [Formula: see text] were observed at [Formula: see text]. Our analysis indicates a sinusoidally modulated magnetic structure with amplitude of 2.0(1) [Formula: see text]/Ce, where the magnetic moments point to the [Formula: see text]-axis. The intensity of the third-order harmonic at 0.8 K is 1/30 as small as that expected for an antiphase structure, suggesting that the modulated structure remains at least down to 0.8 K. Both the magnetization and magnetoresistance show several anomalies in the magnetically ordered phase, indicating field-induced successive changes of the magnetic structure.
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Affiliation(s)
- Takahiro Onimaru
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
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7
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Hashikuni K, Suekuni K, Usui H, Chetty R, Ohta M, Kuroki K, Takabatake T, Watanabe K, Ohtaki M. Thermoelectric Properties and Electronic Structures of CuTi2S4 Thiospinel and Its Derivatives: Structural Design for Spinel-Related Thermoelectric Materials. Inorg Chem 2019; 58:1425-1432. [DOI: 10.1021/acs.inorgchem.8b02955] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Katsuaki Hashikuni
- Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Koichiro Suekuni
- Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
- Transdisciplinary Research and Education Center for Green Technologies, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Hidetomo Usui
- Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Raju Chetty
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Michihiro Ohta
- Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Kazuhiko Kuroki
- Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Toshiro Takabatake
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashihiroshima 739-8530, Japan
| | - Kosuke Watanabe
- Transdisciplinary Research and Education Center for Green Technologies, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
| | - Michitaka Ohtaki
- Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
- Transdisciplinary Research and Education Center for Green Technologies, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
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8
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Inui M, Suekuni K, Kajihara Y, Hosokawa S, Takabatake T, Nakajima Y, Matsuda K, Ohara K, Uchiyama H, Tsutsui S. Static and dynamic structures of liquid Ba 8Ga 16Sn 30: a melt of the thermoelectric clathrate compounds. J Phys Condens Matter 2018; 30:455101. [PMID: 30251705 DOI: 10.1088/1361-648x/aae3f3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
X-ray diffraction and inelastic x-ray scattering measurements of liquid Ba8Ga16Sn30 have been carried out to investigate local structure and atomic dynamics in the liquid. The pair distribution function shows shorter and longer interatomic distances in the first coordination shell. The dynamic structure factor exhibits the inelastic excitations on both sides of the quasielastic central peak. The inelastic excitations disperse with increasing the momentum transfer, suggesting the longitudinal acoustic mode. We found a low energy excitation in addition to the longitudinal acoustic excitation in the dynamic structure factor and it reminds us a strong relationship with a rattling motion of a guest (Ba) atom in the solid state. The temperature dependence of the pair distribution function and the longitudinal acoustic excitation energy is very weak in a range from 600 to 900 °C. The result suggests that Ba and other atoms in the melt are located around minimum positions of the effective pair potential approximated as a harmonic one.
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Affiliation(s)
- M Inui
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 7319-8521, Japan
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9
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Yamane Y, Onimaru T, Wakiya K, Matsumoto KT, Umeo K, Takabatake T. Single-Site Non-Fermi-Liquid Behaviors in a Diluted 4f^{2} System Y_{1-x}Pr_{x}Ir_{2}Zn_{20}. Phys Rev Lett 2018; 121:077206. [PMID: 30169096 DOI: 10.1103/physrevlett.121.077206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/03/2018] [Indexed: 06/08/2023]
Abstract
Electrical resistivity ρ(T) and specific heat C(T) measurements have been made on the diluted 4f^{2} system Y(Pr)Ir_{2}Zn_{20}. Both data of ρ and magnetic specific heat C_{m} per Pr ion are well scaled as a function of T/T_{0}, where T_{0} is a characteristic temperature of non-Fermi-liquid (NFL) behaviors. Furthermore, the temperature dependences of ρ and C_{m}/T agree with the NFL behaviors predicted by the two-channel Kondo model for the strong coupling limit. Therefore, we infer that the observed NFL behaviors result from the single-site quadrupole Kondo effect due to the hybridization of the 4f^{2} states with multichannel conduction electrons.
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Affiliation(s)
- Y Yamane
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - T Onimaru
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - K Wakiya
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - K T Matsumoto
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - K Umeo
- Cryogenic and Instrumental Analysis Division, N-BARD, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - T Takabatake
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
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10
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Suekuni K, Lee CH, Tanaka HI, Nishibori E, Nakamura A, Kasai H, Mori H, Usui H, Ochi M, Hasegawa T, Nakamura M, Ohira-Kawamura S, Kikuchi T, Kaneko K, Nishiate H, Hashikuni K, Kosaka Y, Kuroki K, Takabatake T. Retreat from Stress: Rattling in a Planar Coordination. Adv Mater 2018; 30:e1706230. [PMID: 29388262 DOI: 10.1002/adma.201706230] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/06/2017] [Indexed: 06/07/2023]
Abstract
Thermoelectric devices convert heat flow to charge flow, providing electricity. Materials for highly efficient devices must satisfy conflicting requirements of high electrical conductivity and low thermal conductivity. Thermal conductivity in caged compounds is known to be suppressed by a large vibration of guest atoms, so-called rattling, which effectively scatters phonons. Here, the crystal structure and phonon dynamics of tetrahedrites (Cu,Zn)12 (Sb,As)4 S13 are studied. The results reveal that the Cu atoms in a planar coordination are rattling. In contrast to caged compounds, chemical pressure enlarges the amplitude of the rattling vibration in the tetrahedrites so that the rattling atom is squeezed out of the planar coordination. Furthermore, the rattling vibration shakes neighbors through lone pairs of the metalloids, Sb and As, which is responsible for the low thermal conductivity of tetrahedrites. These findings provide a new strategy for the development of highly efficient thermoelectric materials with planar coordination.
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Affiliation(s)
- Koichiro Suekuni
- Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka, 816-8580, Japan
| | - Chul Ho Lee
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan
| | - Hiromi I Tanaka
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
| | - Eiji Nishibori
- Division of Physics, Faculty of Pure and Applied Sciences, Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
| | - Atsushi Nakamura
- Graduate School of Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
| | - Hidetaka Kasai
- Division of Physics, Faculty of Pure and Applied Sciences, Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
| | - Hitoshi Mori
- Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Hidetomo Usui
- Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Masayuki Ochi
- Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Takumi Hasegawa
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Mitsutaka Nakamura
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | | | - Tatsuya Kikuchi
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Koji Kaneko
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
- Materials Sciences Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Hirotaka Nishiate
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan
| | - Katsuaki Hashikuni
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
| | - Yasufumi Kosaka
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
| | - Kazuhiko Kuroki
- Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Toshiro Takabatake
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
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11
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Rousuli A, Sato H, Iga F, Hayashi K, Ishii K, Wada T, Nagasaki T, Mimura K, Anzai H, Ichiki K, Ueda S, Kondo A, Kindo K, Takabatake T, Shimada K, Namatame H, Taniguchi M. Hard x-ray photoemission study of Yb 1-x Zr x B 12: the effects of electron doping on the Kondo insulator YbB 12. J Phys Condens Matter 2017; 29:265601. [PMID: 28443603 DOI: 10.1088/1361-648x/aa6f70] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have carried out hard x-ray photoemission spectroscopy (HAXPES) of Yb1-x Zr x B12 ([Formula: see text]) to study the effects of electron doping on the Kondo insulator YbB12. The Yb valences of Yb1-x Zr x B12 at 300 K estimated from the Yb 3d HAXPES spectra decreased after substituting Yb with Zr from 2.93 for YbB12 to 2.83 for Yb0.125Zr0.875B12. A temperature dependent valence decrease was found upon cooling for all doping concentrations. We found peak shifts of the B 1s and Zr 3d5/2, and Yb3+ 4f spectra toward the deeper binding-energy with increasing Zr concentration, which indicates a shift of the Fermi level to the higher energy and that of the Yb 4f hole level close to the Fermi level, respectively, due to electron doping. These results qualitatively show the enhanced hybridization between the Yb 4f and conduction-band states with Zr substitution, consistent with magnetic susceptibility measurements.
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Affiliation(s)
- A Rousuli
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
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12
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Kosaka Y, Suekuni K, Hashikuni K, Bouyrie Y, Ohta M, Takabatake T. Effects of Ge and Sn substitution on the metal–semiconductor transition and thermoelectric properties of Cu12Sb4S13 tetrahedrite. Phys Chem Chem Phys 2017; 19:8874-8879. [DOI: 10.1039/c7cp00351j] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The substitutions of Ge and Sn for Cu in Cu12Sb4S13 tetrahedrite lead to the suppression of the metal–semiconductor transition and enhancement of the thermoelectric performance.
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Affiliation(s)
- Yasufumi Kosaka
- Department of Quantum Matter
- Graduate School of Advanced Sciences of Matter
- Hiroshima University
- Higashi-Hiroshima
- Japan
| | - Koichiro Suekuni
- Department of Applied Science for Electronics and Materials
- Interdisciplinary Graduate School of Engineering Sciences
- Kyushu University
- Kasuga
- Japan
| | - Katsuaki Hashikuni
- Department of Quantum Matter
- Graduate School of Advanced Sciences of Matter
- Hiroshima University
- Higashi-Hiroshima
- Japan
| | - Yohan Bouyrie
- Research Institute for Energy Conservation
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Michihiro Ohta
- Research Institute for Energy Conservation
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Toshiro Takabatake
- Department of Quantum Matter
- Graduate School of Advanced Sciences of Matter
- Hiroshima University
- Higashi-Hiroshima
- Japan
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13
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Stockert U, Sun P, Oeschler N, Steglich F, Takabatake T, Coleman P, Paschen S. Giant Isotropic Nernst Effect in an Anisotropic Kondo Semimetal. Phys Rev Lett 2016; 117:216401. [PMID: 27911533 DOI: 10.1103/physrevlett.117.216401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Indexed: 06/06/2023]
Abstract
The "failed Kondo insulator" CeNiSn has long been suspected to be a nodal metal, with a node in the hybridization matrix elements. Here we carry out a series of Nernst effect experiments to delineate whether the severely anisotropic magnetotransport coefficients do indeed derive from a nodal metal or can simply be explained by a highly anisotropic Fermi surface. Our experiments reveal that despite an almost twentyfold anisotropy in the Hall conductivity, the large Nernst signal is isotropic. Taken in conjunction with the magnetotransport anisotropy, these results provide strong support for an isotropic Fermi surface with a large anisotropy in quasiparticle mass derived from a nodal hybridization.
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Affiliation(s)
- Ulrike Stockert
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Peijie Sun
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Niels Oeschler
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Frank Steglich
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Toshiro Takabatake
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Piers Coleman
- Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08855, USA
- Department of Physics, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
| | - Silke Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
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14
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Kim J, Lee K, Takabatake T, Kim H, Kim M, Jung MH. Corrigendum: Magnetic Transition to Antiferromagnetic Phase in Gadolinium Substituted Topological Insulator Bi2Te3. Sci Rep 2015; 5:12182. [PMID: 26174370 PMCID: PMC4502429 DOI: 10.1038/srep12182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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15
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Tokiwa Y, Stingl C, Kim MS, Takabatake T, Gegenwart P. Characteristic signatures of quantum criticality driven by geometrical frustration. Sci Adv 2015; 1:e1500001. [PMID: 26601165 PMCID: PMC4640633 DOI: 10.1126/sciadv.1500001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 03/26/2015] [Indexed: 05/17/2023]
Abstract
Geometrical frustration describes situations where interactions are incompatible with the lattice geometry and stabilizes exotic phases such as spin liquids. Whether geometrical frustration of magnetic interactions in metals can induce unconventional quantum critical points is an active area of research. We focus on the hexagonal heavy fermion metal CeRhSn, where the Kondo ions are located on distorted kagome planes stacked along the c axis. Low-temperature specific heat, thermal expansion, and magnetic Grüneisen parameter measurements prove a zero-field quantum critical point. The linear thermal expansion, which measures the initial uniaxial pressure derivative of the entropy, displays a striking anisotropy. Critical and noncritical behaviors along and perpendicular to the kagome planes, respectively, prove that quantum criticality is driven be geometrical frustration. We also discovered a spin flop-type metamagnetic crossover. This excludes an itinerant scenario and suggests that quantum criticality is related to local moments in a spin liquid-like state.
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Affiliation(s)
- Yoshifumi Tokiwa
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Corresponding author. E-mail:
| | - Christian Stingl
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Moo-Sung Kim
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Toshiro Takabatake
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Philipp Gegenwart
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
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16
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Christensen S, Avila MA, Suekuni K, Piltz R, Takabatake T, Christensen M. Combined X-ray and neutron diffraction study of vacancies and disorder in the dimorphic clathrate Ba8Ga16Sn30 of type I and VIII. Dalton Trans 2014; 42:14766-75. [PMID: 23982481 DOI: 10.1039/c3dt51328a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report detailed structural investigations of the dimorphic clathrate Ba8Ga16Sn30 that crystallizes in both type I and VIII clathrate structures. Single crystals of type I and VIII have been examined using single crystal X-ray and Laue neutron diffraction in the temperature range T = 10 K-500 K. The utilization of both X-ray and neutron diffraction gives a unique ability to reveal the occurrence of minute vacancy occupancies in the host structure. The vacancies are shown to be located on the 6c (type I) and 24g (type VIII) framework sites. Largest vacancy densities are observed for type I p-Ba8Ga16Sn30, 1.3(4)%, and type VIII n-Ba8Ga16Sn30, 0.7(2)%. The relation between guest atom disorder and occurrence of glasslike thermal conductivity in intermetallic clathrates was also investigated. In type VIII Ba8Ga16Sn30 neither n-type (crystalline thermal conductivity) nor p-type (glasslike thermal conductivity) showed any significant disorder of the guest atoms; they do however show anharmonic motion. The glasslike thermal conductivity of p-type Ba8Ga16Sn30 is interpretable as a result of higher effective mass of p-type charge-carriers affecting phonon scattering. In type I Ba8Ga16Sn30 guest atoms are highly disordered for both carrier types and samples of both charge carrier types have glasslike thermal conductivity.
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Affiliation(s)
- Sebastian Christensen
- Department of Inorganic Chemistry & iNano, Aarhus University, DK-8000 Aarhus, Denmark.
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17
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Onimaru T, Matsumoto KT, Nagasawa N, Inoue YF, Umeo K, Tamura R, Nishimoto K, Kittaka S, Sakakibara T, Takabatake T. Nonmagnetic ground states and phase transitions in the caged compounds PrT2Zn20 (T = Ru, Rh and Ir). J Phys Condens Matter 2012; 24:294207. [PMID: 22773390 DOI: 10.1088/0953-8984/24/29/294207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We performed electrical resistivity ρ, magnetic susceptibility χ, specific heat C and electron diffraction measurements on single-crystalline samples of PrT2Zn20 (T = Ru, Rh and Ir). The three compounds show the Van Vleck paramagnetic behavior, indicating the nonmagnetic crystalline electric field (CEF) ground states. A Schottky-type peak appears at around 14 K, irrespective of the T element, which can be moderately reproduced by a doublet–triplet model. For T = Ru, a structural transition occurs at Ts = 138 K, below which no phase transition appears down to 0.04 K. On the other hand, for T = Ir, antiferroquadrupole (AFQ) ordering arising from the nonmagnetic Γ3 doublet takes place at TQ = 0.11 K. For T = Rh, despite a structural transition between 170 and 470 K, the CEF ground state is still the non-Kramers Γ3 doublet. However, no phase transition due to the Γ3 doublet was observed even down to 0.1 K.
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Affiliation(s)
- T Onimaru
- AdSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan.
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18
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Nishimura M, Daino K, Takabatake T, Fukuda M, Tanaka I, Takabatake M, Imaoka T, Kakinuma S, Shimada Y. 725 Genome-wide Changes of Radiation-induced Mammary Carcinoma of (Sprague-Dawley & Copenhagen) F1 Hybrid Rats Overlapping With Those of Human Breast Cancers. Eur J Cancer 2012. [DOI: 10.1016/s0959-8049(12)71366-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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19
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Alekseev PA, Mignot JM, Nemkovski KS, Rybina AV, Lazukov VN, Ivanov AS, Iga F, Takabatake T. Interplay of low-energy phonons and magnetic excitations in the Kondo insulator YbB12. J Phys Condens Matter 2012; 24:205601. [PMID: 22510752 DOI: 10.1088/0953-8984/24/20/205601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Peculiarities in the lattice dynamics of the Kondo insulator Y bB(12) have been studied by inelastic neutron scattering. Selected phonon modes were traced above and below the temperature region (T ~ 50 K) where the gap opens in the electron density of states. The intensities of some low-energy modes exhibit an anomalous temperature dependence for q vectors close to the Brillouin zone boundary, suggesting a renormalization of the phonon eigenvectors. This effect is thought to arise from a coupling with magnetic excitations of the same symmetry, which exist at nearby energies. It is argued that this magnetovibrational coupling may in turn play a role in the steep temperature crossover existing in Y bB(12) between the low-temperature (Kondo insulator) and high-temperature (incoherent spin-fluctuation) regimes, which is rapidly suppressed by lighter Zr substitution.
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Affiliation(s)
- P A Alekseev
- National Research Centre, Kurchatov Institute, Moscow, Russia.
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20
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Matsushita Y, Onimaru T, Matsumoto KT, Sato A, Takabatake T. Crystal structures of new superconducting compounds, Ln T2Zn 20(Ln = La, Pr, T= Ru, Ir). Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311079591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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21
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Hiroto T, Muro Y, Yaguchi H, Tokunaga M, Takabatake T, Tamura R. Physical properties of the Cd 6R1/1 approximants. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311084212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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22
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Onimaru T, Matsumoto KT, Inoue YF, Umeo K, Sakakibara T, Karaki Y, Kubota M, Takabatake T. Antiferroquadrupolar ordering in a Pr-based superconductor PrIr(2)Zn(20). Phys Rev Lett 2011; 106:177001. [PMID: 21635057 DOI: 10.1103/physrevlett.106.177001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Indexed: 05/30/2023]
Abstract
An antiferroquadrupolar ordering at T(Q)=0.11 K has been found in a Pr-based superconductor PrIr(2)Zn(20). The measurements of specific heat and magnetization revealed the non-Kramers Γ(3) doublet ground state with the quadrupolar degrees of freedom. The specific heat exhibits a sharp peak at T(Q)=0.11 K. The increment of T(Q) in magnetic fields and the anisotropic B-T phase diagram are consistent with the antiferroquadrupolar ordered state below T(Q). The entropy release at T(Q) is only 20% of Rln2, suggesting that the quadrupolar fluctuations play a role in the formation of the superconducting pairs below T(c)=0.05 K.
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Affiliation(s)
- T Onimaru
- Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan.
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23
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Shimada Y, Nishimura M, Amasaki Y, Shang Y, Yamauchi K, Sawai T, Hirano S, Imaoka T, Yamada Y, Takabatake T, Kakinuma S. Interaction of low dose radiation and other factors. Health Phys 2011; 100:278-279. [PMID: 21595068 DOI: 10.1097/hp.0b013e3182080e07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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24
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Kimura SI, Iizuka T, Miyazaki H, Irizawa A, Muro Y, Takabatake T. Electronic-structure-driven magnetic ordering in a Kondo semiconductor CeOs2Al10. Phys Rev Lett 2011; 106:056404. [PMID: 21405416 DOI: 10.1103/physrevlett.106.056404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Indexed: 05/30/2023]
Abstract
We report the anisotropic changes in the electronic structure of a Kondo semiconductor CeOs(2)Al(10) across an anomalous antiferromagnetic ordering temperature (T(0)) of 29 K, using optical conductivity spectra. The spectra along the a and c axes indicate that an energy gap due to the hybridization between conduction bands and nearly local 4f states, namely the c-f hybridization gap, emerges from a higher temperature continuously across T(0). Along the b axis, on the other hand, another energy gap with a peak at 20 meV becomes visible at 39 K (>T(0)) and fully opens at T(0) because of a charge instability. This result implies that the appearance of the energy gap, as well as the change in the electronic structure along the b axis, induces the antiferromagnetic ordering below T(0).
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Affiliation(s)
- Shin-ichi Kimura
- UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan.
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25
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Mori T, Iwamoto K, Kushibiki S, Honda H, Matsumoto H, Toyota N, Avila MA, Suekuni K, Takabatake T. Optical conductivity spectral anomalies in the off-center rattling system β-Ba8Ga16Sn30. Phys Rev Lett 2011; 106:015501. [PMID: 21231752 DOI: 10.1103/physrevlett.106.015501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Indexed: 05/30/2023]
Abstract
We present optical conductivity studies of the type-I clathrate Ba8Ga16Sn30, using a terahertz time-domain spectrometer (0.3-3.0 THz). The lowest-lying spectral peak at 0.72 THz due to the Ba(2) ion's off-center vibration in the oversized cage shows a drastic and anomalous temperature dependence. Below about 100 K, the single broad peak splits into two subpeaks, and with further lowering of the temperature, the spectral shape of this so-called rattling phonon shows non-Boltzmann broadening to the point that the linewidth becomes comparable to the peak frequency. Whereas the initial splitting can be understood by assuming a multiwell anharmonic potential, the strong linewidth broadening toward low temperature cannot, since the Boltzmann factor generally sharpens the low-temperature spectra. The observed behavior suggests strong interaction between the local anharmonic phonons and other excitations.
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Affiliation(s)
- T Mori
- Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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26
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27
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Sengupta K, Forthaus MK, Kubo H, Katoh K, Umeo K, Takabatake T, Abd-Elmeguid MM. Geometrical frustration versus magnetic order in the heavy-fermion antiferromagnet YbAgGe under high pressure. Phys Rev B 2010; 81:125129. [DOI: 10.1103/physrevb.81.125129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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28
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29
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Miyoshi-Imamura T, Kakinuma S, Kaminishi M, Okamoto M, Takabatake T, Nishimura Y, Imaoka T, Nishimura M, Murakami-Murofushi K, Shimada Y. Unique Characteristics of Radiation-Induced Apoptosis in the Postnatally Developing Small Intestine and Colon of Mice. Radiat Res 2009; 173:310-8. [DOI: 10.1667/rr1905.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- T. Miyoshi-Imamura
- Genetic Counseling Program, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - S. Kakinuma
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - M. Kaminishi
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - M. Okamoto
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - T. Takabatake
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Y. Nishimura
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - T. Imaoka
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - M. Nishimura
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - K. Murakami-Murofushi
- Genetic Counseling Program, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Y. Shimada
- Experimental Radiology for Children's Health Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
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30
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Tang J, Kumashiro R, Ju J, Li Z, Avila MA, Suekuni K, Takabatake T, Guo F, Kobayashi K, Tanigaki K. Erratum to ‘p- and n-Type Ba8Ga16Ge30 studied by X-ray photoelectron spectroscopy’ [Chem. Phys. Lett. 472 (2009) 60]. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.03.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Hayashi H, Kawamura N, Mizumaki M, Takabatake T. Probe for Spin- and Valence-Selective X-ray Absorption Fine Structure Spectroscopy: EuLγ4 Emission. Anal Chem 2009; 81:1522-8. [DOI: 10.1021/ac802145t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hisashi Hayashi
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo, Tokyo 112-8681, Japan, SPring-8, JASRI, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan, and Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Naomi Kawamura
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo, Tokyo 112-8681, Japan, SPring-8, JASRI, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan, and Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Masaichiro Mizumaki
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo, Tokyo 112-8681, Japan, SPring-8, JASRI, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan, and Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Toshiro Takabatake
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo, Tokyo 112-8681, Japan, SPring-8, JASRI, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan, and Graduate School of Advanced Science of Matter, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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32
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Tang J, Li Z, Ju J, Kumashiro R, A. Avila M, Suekuni K, Takabatake T, Guo F, Kobayashi K, Akai K, Tanigaki K. Soft x-ray photoelectron spectroscopy study of type-I clathrates. Sci Technol Adv Mater 2008; 9:044207. [PMID: 27878024 PMCID: PMC5099638 DOI: 10.1088/1468-6996/9/4/044207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 01/28/2009] [Accepted: 11/13/2008] [Indexed: 06/06/2023]
Abstract
Extensive soft x-ray photoelectron spectroscopy studies are performed on Ba8 Ga16 Ge30 (BGG) and Sr8Ga16Ge30 (SGG) single crystals ranging from Fermi to core levels, at a high-energy facility. Valence band x-ray photoelectron spectroscopy (XPS) experiments with theoretical calculations revealed that the valence band is mainly constructed by the Ge/Ga 4s and 4p wave functions with little contribution of the Ba/Sr atomic orbitals. Surprisingly, unexpected features evidencing the different shift for the 2a- and 6d- sites between Ba 4d and Sr 3d are observed. The detailed analyses including theoretical support by first-principles band-structure calculations lead to the conclusion that the component distributions of the larger tetrakaidecahedral cage are different depending on the endohedral atoms, which contrasts with the past consensus that BGG and SGG have the same framework structure. This may give thorough reconsiderations on earlier interpretations of experimental data.
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Affiliation(s)
- Jun Tang
- Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba Aramaki Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Zhaofei Li
- Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba Aramaki Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Jing Ju
- Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba Aramaki Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Ryotaro Kumashiro
- Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba Aramaki Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Marcos A. Avila
- Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Kouichirou Suekuni
- Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Toshiro Takabatake
- Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - FangZhun Guo
- SPring-8, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto Mikazuki-cho Sayo-gun Hyogo 679-5198, Japan
| | - Keisuke Kobayashi
- SPring-8, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto Mikazuki-cho Sayo-gun Hyogo 679-5198, Japan
| | - Koji Akai
- MITC, Yamaguchi University, Tokiwadai 2-16-1, 755-8611 Ube, Japan
| | - Katsumi Tanigaki
- Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba Aramaki Aoba-ku, Sendai, Miyagi 980-8578, Japan
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Yoshii S, Yamamoto T, Hagiwara M, Michimura S, Shigekawa A, Iga F, Takabatake T, Kindo K. Multistep magnetization plateaus in the Shastry-Sutherland system TbB4. Phys Rev Lett 2008; 101:087202. [PMID: 18764654 DOI: 10.1103/physrevlett.101.087202] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 06/18/2008] [Indexed: 05/26/2023]
Abstract
We report high-field magnetization and magnetostriction measurements on the rare-earth-metal tetraboride TbB4, in which the Tb moments form a Shastry-Sutherland lattice in the tetragonal basal plane. A number of magnetization plateaus appear when the magnetic field is perpendicular to the magnetic easy plane. We propose that the magnetization plateaus arise from the combined effect of magnetic frustration and quadrupole interaction in the unique two-dimensional network.
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Affiliation(s)
- S Yoshii
- KYOKUGEN, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
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Takasu Y, Hasegawa T, Ogita N, Udagawa M, Avila MA, Suekuni K, Takabatake T. Off-center rattling and anisotropic expansion of type-I clathrates studied by Raman scattering. Phys Rev Lett 2008; 100:165503. [PMID: 18518215 DOI: 10.1103/physrevlett.100.165503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Indexed: 05/26/2023]
Abstract
Dynamical motions of the guest ions in type-I clathrates Sr8Ga16Si(30-x)Gex and Ba8Ga16Si(30-x)Gex have been studied by Raman scattering spectroscopy, to clarify the role of guest vibration modes in these systems with unusual thermal transport behaviors. An anomalous decrease of the guest energies with decreasing temperature is observed for both systems. The Ge-doping expands the cage surrounding the 6d site anisotropically for Sr8Ga16Si(30-x)Gex, but isotropically for Ba8Ga16Si(30-x)Gex. Especially for Sr8Ga16Si(30-x)Gex, off-center rattling arises simultaneously with the anisotropic expansion, and it is confirmed that these anomalies play a crucial role to suppress lattice thermal conductivity in these systems.
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Affiliation(s)
- Y Takasu
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8521, Japan
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Takasu Y, Hasegawa T, Ogita N, Udagawa M, Suekuni K, Avila MA, Takabatake T. Raman scattering of type-I clathrate compounds: A8Ga16Ge30(A = Eu, Sr, Ba) and Sr8Ga16Si30-xGex. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/92/1/012151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kitagawa J, Kadoya Y, Tsubota M, Iga F, Takabatake T. Terahertz conductivity of localized photoinduced carriers in a Mott insulator YTiO(3) at low excitation density, contrasted with the metallic nature in a band semiconductor Si. J Phys Condens Matter 2007; 19:406224. [PMID: 22049122 DOI: 10.1088/0953-8984/19/40/406224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We performed optical-pump terahertz-probe measurements of a Mott insulator YTiO(3) and a band semiconductor Si using a laser diode (1.47 eV) and a femtosecond-pulse laser (1.55 eV). Both samples possess long energy-relaxation times (1.5 ms for YTiO(3) and 15 µs for Si); therefore, it is possible to extract terahertz complex conductivities of photoinduced carriers under equilibrium. We observed highly contrasting behaviour-Drude conductivity in Si and localized conductivity possibly obeying the Jonscher law in YTiO(3). The carrier number at the highest carrier-concentration layer in YTiO(3) is estimated to be 0.015 per Ti site. Anisotropic conductivity of YTiO(3) is determined. Our study indicates that localized carriers might play an important role in the incipient formation of photoinduced metallic phases in Mott insulators. In addition, this study shows that the transfer-matrix method is effective for extracting an optical constant of a sample with a spatially inhomogeneous carrier distribution.
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Affiliation(s)
- J Kitagawa
- Department of Quantum Matter, ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan
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Nemkovski KS, Mignot JM, Alekseev PA, Ivanov AS, Nefeodova EV, Rybina AV, Regnault LP, Iga F, Takabatake T. Polarized-neutron study of spin dynamics in the Kondo insulator YbB12. Phys Rev Lett 2007; 99:137204. [PMID: 17930630 DOI: 10.1103/physrevlett.99.137204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Indexed: 05/25/2023]
Abstract
Inelastic neutron scattering experiments have been performed on the archetype compound YbB(12), using neutron polarization analysis to separate the magnetic signal from the phonon background. With decreasing temperature, components characteristic for a single-site spin-fluctuation dynamics are suppressed, giving place to specific, strongly Q-dependent, low-energy excitations near the spin-gap edge. This crossover is discussed in terms of a simple crystal-field description of the incoherent high-temperature state and a predominantly local mechanism for the formation of the low-temperature singlet ground state.
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Affiliation(s)
- K S Nemkovski
- LNSR, ISSSP, Russian Research Centre Kurchatov Institute, 123182 Moscow, Russia
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Alekseev PA, Nemkovski KS, Mignot JM, Ivanov AS, Nefeodova EV, Sadikov IP, Iga F, Takabatake T. Dynamical magnetic correlations in the YbB12 kondo insulator: Neutron investigations with a polarization analysis. CRYSTALLOGR REP+ 2007. [DOI: 10.1134/s1063774507030066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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39
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Nemkovski KS, Alekseev PA, Rybina AV, Mignot JM, Flachbart K, Samuely P, Shitsevalova NY, Paderno YB, Iga F, Takabatake T, Lazukov VN, Nefeodova EV, Sadikov IP, Tiden NN, Bewley RI. Dynamics of boron nanoclusters in RB12 (R = Yb, Lu) systems. CRYSTALLOGR REP+ 2006. [DOI: 10.1134/s1063774506070200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Nemkovski K, Alekseev P, Mignot JM, Rybina A, Iga F, Takabatake T, Shitsevalova N, Paderno Y, Lazukov V, Nefeodova E, Tiden N, Sadikov I. Lattice dynamics in the Kondo insulator YbB12. J SOLID STATE CHEM 2006. [DOI: 10.1016/j.jssc.2006.01.061] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Schenck A, Gygax FN, Umeo K, Takabatake T, Andreica D. Anisotropic 4f-spin dynamics across the B-T phase diagram of Ce(7)Ni(3). J Phys Condens Matter 2006; 18:1955-1966. [PMID: 21697568 DOI: 10.1088/0953-8984/18/6/011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Longitudinal field μSR measurements in applied fields parallel and perpendicular to the c-axis of the hexagonal heavy-fermion antiferromagnet Ce(7)Ni(3) served to monitor the 4f-spin dynamics across the magnetic phase diagram in the B-T plane, which consists of an incommensurate/commensurate antiferromagnetic (AF) section below 1.9 K/0.7 K and below an applied field B of 0.25 T, and for B along the c-axis, of a field-induced magnetic (FIM) section for B≥0.6 T and below 0.5 K. The observed μ(+) spin-lattice relaxation rates reveal persisting spin dynamics across the whole phase diagram, reflect the various phase boundaries and are interpreted to arise in the AF and FIM phases from the Ce3 sublattice (the Ce ions are located on three different sublattices) and in the intermediate phase, viewed as a short range ordered (SRO) state, also from the Ce1 and Ce2 sublattices with slower fluctuation rates. In the paramagnetic regime the Ce1 sublattice displays the slowest spin dynamics. In the FIM phase the fraction of relaxing μ(+) appears to shrink with rising B, evidencing a possible phase separation.
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Affiliation(s)
- A Schenck
- Institute for Particle Physics, ETH Zürich, CH-5232 Villigen PSI, Switzerland
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Kozlova N, Hagel J, Doerr M, Wosnitza J, Eckert D, Müller KH, Schultz L, Opahle I, Elgazzar S, Richter M, Goll G, von Löhneysen H, Zwicknagl G, Yoshino T, Takabatake T. Magnetic-field-induced band-structure change in CeBiPt. Phys Rev Lett 2005; 95:086403. [PMID: 16196877 DOI: 10.1103/physrevlett.95.086403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Indexed: 05/04/2023]
Abstract
We report on a field-induced change of the electronic band structure of CeBiPt as evidenced by electrical-transport measurements in pulsed magnetic fields. Above approximately 25 T, the charge-carrier concentration increases nearly 30% with a concomitant disappearance of the Shubnikov-de Haas signal. These features are intimately related to the Ce 4f electrons since for the non-4f compound LaBiPt the Fermi surface remains unaffected. Electronic band-structure calculations point to a 4f-polarization-induced change of the Fermi-surface topology.
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Affiliation(s)
- N Kozlova
- Institut für Festkörper- und Werkstoffforschung Dresden, D-01171 Dresden, Germany
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Fukuoka H, Yamanaka S, Matsuoka E, Takabatake T. High-Pressure Synthesis and Transport Properties of a New Binary Germanide, SrGe6-δ (δ ≅ 0.5), with a Cagelike Structure. Inorg Chem 2005; 44:1460-5. [PMID: 15732987 DOI: 10.1021/ic0485615] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new germanide, SrGe6-delta (delta congruent with 0.5), was synthesized by the reaction of Sr and Ge mixtures under a pressure of 5 GPa at 1200 degrees C. It crystallized in the orthorhombic space group Cmcm (No. 63) with a = 4.0981(6) A, b = 11.159(1) A, c = 12.6825(8) A, V = 580.0(1) A3, and Z = 4. SrGe6-delta is composed of a Ge covalent network having a cagelike structure and Sr atoms situated in the cages. Each Ge atom is coordinated by four neighboring Ge atoms. The coordination polyhedra are fairly distorted from an ideal tetrahedron, and the Ge network contains vacancies and disordering. The resistivity shows metallic behavior down to 2 K, and the positive thermoelectric power indicates the dominant carriers to be holes.
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Affiliation(s)
- Hiroshi Fukuoka
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan.
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Iga F, Tsubota M, Sawada M, Huang HB, Kura S, Takemura M, Yaji K, Nagira M, Kimura A, Jo T, Takabatake T, Namatame H, Taniguchi M. Determination of the orbital polarization in YTiO3 by using soft X-ray linear dichroism. Phys Rev Lett 2004; 93:257207. [PMID: 15697937 DOI: 10.1103/physrevlett.93.257207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Indexed: 05/24/2023]
Abstract
We report measurements of linear dichroism in x-ray absorption at Ti L(2,3) edges of a Mott-insulating ferromagnet YTiO3, where orbital ordering occurs in the triply degenerate Ti 3d t(2g) states. Dichroic spectra and their integrated intensities are obtained for the incident electric field with polarizations parallel to a, b, and c axes. The comparison of the spectra with atomic multiplet calculations removes the ambiguity about the orbital polarization, i.e., the relative weights of |xy>, |yz>, and |zx> orbits, which are crucial for the origin of ferromagnetism. The result is consistent with the previous analysis of nuclear magnetic resonance in the Mizokawa-Fujimori scheme.
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Affiliation(s)
- F Iga
- Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
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Tanaka S, Tanaka IB, Sasagawa S, Ichinohe K, Takabatake T, Matsushita S, Matsumoto T, Otsu H, Sato F. No lengthening of life span in mice continuously exposed to gamma rays at very low dose rates. Radiat Res 2003; 160:376-9. [PMID: 12926996 DOI: 10.1667/rr3042] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Late effects of continuous exposure to ionizing radiation are potential hazards to workers in radiation facilities as well as to the general public. Recently, low-dose-rate and low-dose effects have become a serious concern. Using a total of 4000 mice, we studied the late biological effects of chronic exposure to low-dose-rate radiation as assayed by life span. Two thousand male and 2000 female 8-week-old specific-pathogen-free (SPF) B6C3F1 mice were randomly divided into four groups (one nonirradiated control and three irradiated). Irradiation was carried out for approximately 400 days using (137)Cs gamma rays at dose rates of 21 mGy day(-1), 1.1 mGy day(-1) and 0.05 mGy day(-1) with total doses equivalent to 8000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept under SPF conditions until they died spontaneously. Statistical analyses showed that the life spans of mice of both sexes irradiated with 21 mGy day(-1) (P < 0.0001) and of females irradiated with 1.1 mGy day(-1) (P < 0.05) were significantly shorter than those of the control group. Our results show no evidence of lengthened life span in mice continuously exposed to very low dose rates of gamma rays.
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Affiliation(s)
- S Tanaka
- Department of Radiobiology, Institute for Environmental Sciences, 1-7, Ienomae, Obuchi, Rokkasho-mura, Kamikita-gun, Aomori 039-3212, Japan.
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Kato K, Nishibori E, Takata M, Sakata M, Nakano T, Uchihira K, Tsubota M, Iga F, Takabatake T. The metal-insulator transition in Y1−xCaxTiO3caused by structural phase separation. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302090906] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Takahashi M, Dogane I, Yoshida M, Yamachika H, Takabatake T, Bersohn M. The performance of a noninteractive synthesis program. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/ci00068a015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
A reaction from various kinds of nitroquinoline with hydroxylamine in potassium hydroxide alkalinity produced a novel product, furazanoquinoline, besides the known amino derivatives. The products obtained were furazano [3,4-f] quinoline (5) from 5-nitroquinoline (1) and 6-nitroquinoline (6), and furazano [3,4-h] quinoline (10) from 7-nitroquinoline (8) and 8-nitroquinoline (11). The reaction mechanism was believed to be as shown in Figs. 2 and 3. The photoreaction of benzofuroxan (19) in acetonitrile containing a little water, under a high pressure mercury lamp, produced 1H-azepine-2,7-dione (20), while under irradiation using a low pressure lamp, 6H-furazano [4,5-c] carbazole-3-oxide (21) and compound 20 were obtained. Then the photoproduct 20 produced photodimer 22 by irradiation in acetonitrile: water (9:1, v/v) using a high or low pressure mercury lamp, while photolysis with alkali proceeded as in the photoreaction of N-alkylimide to give 7-hydroxy-1H-azepine-2-one (23). When pyrido [2,3-c] furoxan (24) was irradiated in acetonitrile containing a little water with a low pressure mercury lamp, 3-nitro-2-pyridone (25) was obtained. When compound 24 was irradiated in the presence of morpholine with a low pressure mercury lamp in an argon atmosphere, 6-morpholinopyridine 2,3-dioxime (26) was produced. Quinoxaline 1,4-dioxide derivatives (31, 33), phenazine 5,10-dioxide derivatives (36, 37) and pyrido [2,3-b] pyrazine derivatives (38, 39) were synthesized from the corresponding furoxan catalyzed by silica gel or molecular sieves, and their antibacterial properties were evaluated. The results of antibacterial screening tests in vitro, revealed strong activity against Bacteroides fragilis.
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Affiliation(s)
- M Hasegawa
- College of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi-shi, Chiba 274-8555, Japan
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Kawabata M, Kasuga S, Hara H, Suyama S, Moriyama K, Takabatake T. Erythropoietin-resistant refractory renal anemia: effects of oral L-carnitine supplementation. Clin Nephrol 2001; 55:265-6. [PMID: 11316253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
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Abstract
OBJECTIVES We analyzed the regulatory function of reactive oxygen species (ROS) on the hypertrophic signaling in adult rat cardiac myocytes: BACKGROUND The ROS regulate mitogenic signal transduction in various cell types. In neonatal rat cardiac myocyte, antioxidants have been shown to inhibit cardiac hypertrophy, and ROS are suggested to modulate the hypertrophic signaling. However, the conclusion may not reflect the situation of mature heart, because of the different natures between neonatal and adult cardiac myocytes. METHODS Cultured adult rat cardiac myocytes were stimulated with endothelin-1 (ET-1) or phenylephrine (PE), and intracellular ROS levels, the activities of mitogen-activated protein kinases (MAPKs; ERK, p38, and JNK), and 3H-phenylalanine incorporation were examined. We also examined the effects of antioxidant pretreatment of myocytes on MAPK activities and cardiac hypertrophy to analyze the modulatory function of redox state on MAPK-mediated hypertrophic signaling. RESULTS The ROS levels in ET-1- or PE-stimulated myocytes were maximally increased at 5 min after stimulation. The origin of ROS appears to be from NADH/NADPH oxidase, because the increase in ROS was suppressed by pretreatment of myocytes with NADH/NADPH oxidase inhibitor diphenyleneiodonium. Extracellular signal-regulated kinase (ERK) activity was increased by the stimulation of ET-1 or PE. In contrast, p38 and c-Jun-N-terminal protein kinase (JNK) activities did not change after these stimulations. Antioxidant treatment of myocytes suppressed the increase in ROS and blocked ERK activation and the subsequent cardiac hypertrophy induced by these stimuli. CONCLUSIONS These data demonstrate that ROS mediate signal transduction of cardiac hypertrophy induced by ET-1 or PE in adult rat cardiac myocytes.
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Affiliation(s)
- K Tanaka
- 4th Department of Internal Medicine, Shimane Medical University, Japan.
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