2001 Fiscal Year Annual Research Report

軌道縮退系の電子構造

Research Project

Project/Area Number	11220203
Research Institution	Tohoku University
Principal Investigator	青木晴善東北大学, 極低温科学センター, 教授 (60302246)
Co-Investigator(Kenkyū-buntansha)	高木滋東北大学, 大学院・理学研究科, 助教授 (20154750) 高橋隆東北大学, 大学院・理学研究科, 教授 (00142919) 國井暁東北大学, 大学院・理学研究科, 教授 (10004368) 中村慎太郎東北大学, 極低温科学センター, 助教授 (20292310) 落合明東北大学, 極低温科学センター, 助教授 (90183772)
Keywords	軌道秩序 / 高温強磁性 / 四重極転移 / CaB_6 / BeB_6 / RB_2C_2
Research Abstract	1.高温弱強磁性高輝度X線による磁性不純物の蛍光分析を行い、CaB_6の強磁性がFe不純物によるものではないことを確認した。また、CaB_6のBを一部Cにより置き換えることによっても強磁性が発現することを見出した。高分解能角度分解光電子分光を行い、バンド分散を決定し、excitonic-nsulator modelが予言しているような「ホールバンドと電子バンドの重なり」は存在しないことを見出した。 2.CeB_6および四重極秩序を示す物質極低温下のCe_xLa_<1-x>B_6の弾性定数C_<44>と熱膨張の測定を行い、C_<44>は低温で弱い温度変化しか示さないこと、また、熱膨張の測定により、I相-IV相転位に伴って、cubicからtrigonalへ自発的に変型していることを明らかにした。これらの実験結果はCe_xLa_<1-x>B_6のIV相の秩序変数がΓ_5の対称性を持った電気四重極子であることを示唆する。 HoB_2C_2で中性子散乱を行い,いわゆるIV相と呼ばれていた相が,極めて特異な短距離反強磁性相関の強い相であることを明らかにした。 PrPb_3において圧力効果の実験を行い、四重極相互作用は圧力によってほとんど変化しないが、共存する反強磁性相互作用は大きく変化することを明らかにした。 3.その他 Ce及びLaモノカルコゲナイドで純良単結晶を育成し、フェルミ面の詳細と有効質量を決定した(CeSを除く)。また、高分解能角度分解光電子分光により、全てのCe及びLaモノカルコゲナイドでの4fレベル及び他のエネルギーバンドの波数分散を明らかにした。

Research Products

(42 results)

All Other

All Publications (42 results)

[Publications] M.Sera, et al.: "Anomalous Temperature Dependence of the Magnetic Field Induced Antiferrornagnetic Moment in the Antiferroquadrupolar Ordered State of CeB_6"Phys. Rev. Lett.. 86. 1578-1581 (2001)
[Publications] M.Magnuson, et al.: "Electronic-structure investigation of CeB_6 by means of soft-x-ray scattering"Phys. Rev. B. 63. 75101-75105 (2001)
[Publications] S.Kobayashi, et al.: "Anisotropic Magnetic Phase Diagram of PrB_6 Dominated by the O_<xy> Antiferro-Quadrupolar Interaction"J. Phys. Soc. Jpn.. 70. 1721-1730 (2001)
[Publications] H.Nakao, et al.: "Antiferro-Quadrupole ordering of CeB_6 Studied by Resonant X-Ray Scattering"J. Phys. Soc. Jpn.. 70. 1857-1860 (2001)
[Publications] S.A.Granovsky, et al.: "Magnetic and magneto-elastic properties of a single crystal of TbB_6"J. Phys. : Condens. Matter. 13. 6307-6321 (2001)
[Publications] N.E.Sluchanko, et al.: "Low-temperature transport anisotropy and many-body effects in SmB_6"Phys. Rev. B. 64. 153103-153106 (2001)
[Publications] F.Yakhou, et al.: "k=2π/a[1/2 1/2 1/2] zero-field ordering in the intermediate phase of CeB6 observed by X-ray scattering : what orders?"Phys. Lett. A. 485. 191-196 (2001)
[Publications] S.Hane, et al.: "Magnetic phase diagram of Ce_<0.5>La_<0.5>B_6 under high pressure"J. Magn. Magn. Mater.. 226-230. 98-100 (2001)
[Publications] S.Tsutsui, et al.: "^<238>U Mossbauer Study of UPt_3"J. Magn. Magn. Mater.. 226-230. 87-88 (2001)
[Publications] N.Kimura, et al.: "Fermi Surface Change with Antiferro-Quadrupolarn Ordering DyB_2C_2"J. Mag. Magn. Mater.. 226. 1190-1192 (2001)
[Publications] T.Yamamizu, et al.: "DHvA Effect of R(R=La, Ce)_3Pd_<20>Ge_6 under Uniaxial Compression"J. Mag. Magn. Mater.. 226-230. 155-157 (2001)
[Publications] N.Tateiwa, et al.: "Neutron Scattering Study on the Crystal Structure, Magnetic Ordering, and Crystalline Electric Field Excitations in an Uranium Metallic Compound U_3Pd_<20>Si_6"J. Phys. Soc. Jpn.. 70. 2425-2436 (2001)
[Publications] U.Staub, et al.: "Direct observation of 1-dimensinal charge order below the first-order "metal-insulator" transition in Yb_4As_3"Europhys. Lett.. 53. 72-78 (2001)
[Publications] M.Kohgi, et al.: "Staggered field effect on the one-dimensional S=1/2 antiferromagnet Yb_4As_3"Phys. Rev. Lett.. 86. 2439-2442 (2001)
[Publications] N.Nakayama, et al.: "Fermi Sirface of CeTe"J. Mag. Mang. Mater.. 226. 208-210 (2001)
[Publications] K.Iwasa, et al.: "Polarized-neutron study of one-dimensional magnetic response under magnetic field in the charge-ordered phase of Yb_4As_3"J. Mag. Mang. Mater.. 226. 441-443 (2001)
[Publications] P.Gegenwart, et al.: "Low-temperature resistivity and susceptibility of the low-carrier density, one-dimensional S=1/2 antiferromagnet Yb_4As_3"J. Mag. Mang. Mater.. 226. 630-632 (2001)
[Publications] B.Schmidt, et al.: "Low-energy excitations of the semimetallic one-dimensional S=1/2 antiferromagnet Yb_4As_3"Physica B. 300. 121-138 (2001)
[Publications] S.kimura, et al.: "Temperature dependence of low-energy optical conductivity of Yb_4(As_<1-x>P_x)_3 (x0, 0.05, 0.15)"J. Phys. Soc. Jpn.. 70. 2829-2832 (2001)
[Publications] T.Ito, et al.: "Electronic structure and Fermi surface of UC studied by high-resolution angle-resolved photoemission spectroscopy"J. Mag. Mag. Mater.. 226-230. 40-41 (2001)
[Publications] T.Ito, et al.: "High-resolution angle-resolved photoemission sturdy of UN and USb, Dual character of 5f electrons"J. Mag. Mag. Mater.. 226-230. 68-69 (2001)
[Publications] T.Takahashi: "High-resolution photoemission study of strongly correlated f electron systems"J. Electron Spectroscopy and Related Phenonema. 117-118. 311-312 (2001)
[Publications] S.Souma, et al.: "Crystal-field splitting in CeB_6 observed by ultrahigh-resolution photoemission spectroscopy"J. Electron Spectroscopy and Related Phenonema. 117-118. 729-734 (2001)
[Publications] S.Souma, et al.: "Ultrahigh-resolution photoemission study of CePd_3, absence of Kondo-insulator gap"J. Electron Spectroscopy and Related Phenonema. 117-118. 735-740 (2001)
[Publications] M.Magnuson, et al.: "Electronic-structure investigation of CeB_6 by means of soft-x-ray scattering"Phys. Rev. B. 63. 75101 (2001)
[Publications] T.Takhashi, et al.: "High-resolution photoemission study of MgB_2"Phys. Rev. Lett.. 86. 4915-4917 (2001)
[Publications] H.Kumigasira, et al.: "Hybridized Nature of Pseudogap in Kondo Insulators CeRhSb and CeRhAs"Phys. Rev. Lett.. 87. 67206 (2001)
[Publications] A.Donni, et al.: "The Cubic to Trigonal Phase Transition in HoB_6 Measured on the New Powder Neutron Diffractometer HRPT at SINQ"J. Phys. Soc. Jpn.. 70. 448-450 (2001)
[Publications] 松村武: "共鳴X線散乱によるDyB2C2における反強的四重極子秩序の観測"放射光. 15. 3-11 (2002)
[Publications] T.Ito, et al.: "Ultrahigh-resolution angle-resolved photoemission spectroscopy of UPd_3"Pysica B. (印刷中).
[Publications] H.Kumigashira, et al.: "Resonant angle-resolved photoemission study of heavy fermion material CeRu_2Si_2"Pysica B. (印刷中).
[Publications] S.Souma, et al.: "Direct observation of pseudo-gap of SmB_6 ising ultrahigh-resolution photoemission spectroscopy"Pysica B. (印刷中).
[Publications] S.Souma, et al.: "Effect of pressure on the antiferro-quadrupolar transition of CeB_6"J. Phys. Soc. Jpn.. (印刷中).
[Publications] T.Takahashi, et al.: "Angle-resolved photoemission study of novel boride compounds"J. Phys. Soc. Jpn.. (印刷中).
[Publications] A.Chainani, et al.: "Electronic structure of black SmS : I 4d-4f resonance and angle-ontegrated valence-band photoemission spectoscopy"Phys. Rev. B. (印刷中).
[Publications] T.Ito, et al.: "Electronic structure of black SmS : II Angle-resolved photoemission spectroscopy"Phys. Rev. B. (印刷中).
[Publications] T.Ito, et al.: "Ultrahigh-resolution photoemission spectroscopy on UGe_2"J. Phys. Soc. Jpn.. (印刷中).
[Publications] Y.Nemoto, et al.: "Low-temperature behavior of the elastic constant C44 in CexLa1-xB_6"Physica B. (印刷中).
[Publications] S.Nakamura, et al.: "Anisotropy in the magnetic phase diagrams of CexLa1-xB_6"J. Phys. Soc. Jpn.. (印刷中).
[Publications] M.Akatsu, et al.: "Thermal expansion measurements on Ce0.75La0.25B_6"J. Phys. Soc. Jpn.. (印刷中).
[Publications] T.Yamamizu, et al.: "Magnetic Phase Diagram of Ce_3Pd_<20>Ge_6 under Uniaxal Pressure"Physica B. (印刷中).
[Publications] N.Tateiwa, et al.: "Neutron Scattering Experiment on U_3Pd_<20>Si_6 II : Crystalline Electric Field and Spin Wave Excitations and Magnetic Structures"Physica B. (印刷中).

2001 Fiscal Year Annual Research Report

軌道縮退系の電子構造

Principal Investigator

青木 晴善 東北大学, 極低温科学センター, 教授 (60302246)

Research Products

[Publications] M.Sera, et al.: "Anomalous Temperature Dependence of the Magnetic Field Induced Antiferrornagnetic Moment in the Antiferroquadrupolar Ordered State of CeB_6"Phys. Rev. Lett.. 86. 1578-1581 (2001)

[Publications] M.Magnuson, et al.: "Electronic-structure investigation of CeB_6 by means of soft-x-ray scattering"Phys. Rev. B. 63. 75101-75105 (2001)

[Publications] S.Kobayashi, et al.: "Anisotropic Magnetic Phase Diagram of PrB_6 Dominated by the O_<xy> Antiferro-Quadrupolar Interaction"J. Phys. Soc. Jpn.. 70. 1721-1730 (2001)

[Publications] H.Nakao, et al.: "Antiferro-Quadrupole ordering of CeB_6 Studied by Resonant X-Ray Scattering"J. Phys. Soc. Jpn.. 70. 1857-1860 (2001)

[Publications] S.A.Granovsky, et al.: "Magnetic and magneto-elastic properties of a single crystal of TbB_6"J. Phys. : Condens. Matter. 13. 6307-6321 (2001)

[Publications] N.E.Sluchanko, et al.: "Low-temperature transport anisotropy and many-body effects in SmB_6"Phys. Rev. B. 64. 153103-153106 (2001)

[Publications] F.Yakhou, et al.: "k=2π/a[1/2 1/2 1/2] zero-field ordering in the intermediate phase of CeB6 observed by X-ray scattering : what orders?"Phys. Lett. A. 485. 191-196 (2001)

[Publications] S.Hane, et al.: "Magnetic phase diagram of Ce_<0.5>La_<0.5>B_6 under high pressure"J. Magn. Magn. Mater.. 226-230. 98-100 (2001)

[Publications] S.Tsutsui, et al.: "^<238>U Mossbauer Study of UPt_3"J. Magn. Magn. Mater.. 226-230. 87-88 (2001)

[Publications] N.Kimura, et al.: "Fermi Surface Change with Antiferro-Quadrupolarn Ordering DyB_2C_2"J. Mag. Magn. Mater.. 226. 1190-1192 (2001)

[Publications] T.Yamamizu, et al.: "DHvA Effect of R(R=La, Ce)_3Pd_<20>Ge_6 under Uniaxial Compression"J. Mag. Magn. Mater.. 226-230. 155-157 (2001)

[Publications] N.Tateiwa, et al.: "Neutron Scattering Study on the Crystal Structure, Magnetic Ordering, and Crystalline Electric Field Excitations in an Uranium Metallic Compound U_3Pd_<20>Si_6"J. Phys. Soc. Jpn.. 70. 2425-2436 (2001)

[Publications] U.Staub, et al.: "Direct observation of 1-dimensinal charge order below the first-order "metal-insulator" transition in Yb_4As_3"Europhys. Lett.. 53. 72-78 (2001)

[Publications] M.Kohgi, et al.: "Staggered field effect on the one-dimensional S=1/2 antiferromagnet Yb_4As_3"Phys. Rev. Lett.. 86. 2439-2442 (2001)

[Publications] N.Nakayama, et al.: "Fermi Sirface of CeTe"J. Mag. Mang. Mater.. 226. 208-210 (2001)

[Publications] K.Iwasa, et al.: "Polarized-neutron study of one-dimensional magnetic response under magnetic field in the charge-ordered phase of Yb_4As_3"J. Mag. Mang. Mater.. 226. 441-443 (2001)

[Publications] P.Gegenwart, et al.: "Low-temperature resistivity and susceptibility of the low-carrier density, one-dimensional S=1/2 antiferromagnet Yb_4As_3"J. Mag. Mang. Mater.. 226. 630-632 (2001)

[Publications] B.Schmidt, et al.: "Low-energy excitations of the semimetallic one-dimensional S=1/2 antiferromagnet Yb_4As_3"Physica B. 300. 121-138 (2001)

[Publications] S.kimura, et al.: "Temperature dependence of low-energy optical conductivity of Yb_4(As_<1-x>P_x)_3 (x0, 0.05, 0.15)"J. Phys. Soc. Jpn.. 70. 2829-2832 (2001)

[Publications] T.Ito, et al.: "Electronic structure and Fermi surface of UC studied by high-resolution angle-resolved photoemission spectroscopy"J. Mag. Mag. Mater.. 226-230. 40-41 (2001)

[Publications] T.Ito, et al.: "High-resolution angle-resolved photoemission sturdy of UN and USb, Dual character of 5f electrons"J. Mag. Mag. Mater.. 226-230. 68-69 (2001)

[Publications] T.Takahashi: "High-resolution photoemission study of strongly correlated f electron systems"J. Electron Spectroscopy and Related Phenonema. 117-118. 311-312 (2001)

[Publications] S.Souma, et al.: "Crystal-field splitting in CeB_6 observed by ultrahigh-resolution photoemission spectroscopy"J. Electron Spectroscopy and Related Phenonema. 117-118. 729-734 (2001)

[Publications] S.Souma, et al.: "Ultrahigh-resolution photoemission study of CePd_3, absence of Kondo-insulator gap"J. Electron Spectroscopy and Related Phenonema. 117-118. 735-740 (2001)

[Publications] M.Magnuson, et al.: "Electronic-structure investigation of CeB_6 by means of soft-x-ray scattering"Phys. Rev. B. 63. 75101 (2001)

[Publications] T.Takhashi, et al.: "High-resolution photoemission study of MgB_2"Phys. Rev. Lett.. 86. 4915-4917 (2001)

[Publications] H.Kumigasira, et al.: "Hybridized Nature of Pseudogap in Kondo Insulators CeRhSb and CeRhAs"Phys. Rev. Lett.. 87. 67206 (2001)

[Publications] A.Donni, et al.: "The Cubic to Trigonal Phase Transition in HoB_6 Measured on the New Powder Neutron Diffractometer HRPT at SINQ"J. Phys. Soc. Jpn.. 70. 448-450 (2001)

[Publications] 松村 武: "共鳴X線散乱によるDyB2C2における反強的四重極子秩序の観測"放射光. 15. 3-11 (2002)

[Publications] T.Ito, et al.: "Ultrahigh-resolution angle-resolved photoemission spectroscopy of UPd_3"Pysica B. (印刷中).

[Publications] H.Kumigashira, et al.: "Resonant angle-resolved photoemission study of heavy fermion material CeRu_2Si_2"Pysica B. (印刷中).

[Publications] S.Souma, et al.: "Direct observation of pseudo-gap of SmB_6 ising ultrahigh-resolution photoemission spectroscopy"Pysica B. (印刷中).

[Publications] S.Souma, et al.: "Effect of pressure on the antiferro-quadrupolar transition of CeB_6"J. Phys. Soc. Jpn.. (印刷中).

[Publications] T.Takahashi, et al.: "Angle-resolved photoemission study of novel boride compounds"J. Phys. Soc. Jpn.. (印刷中).

[Publications] A.Chainani, et al.: "Electronic structure of black SmS : I 4d-4f resonance and angle-ontegrated valence-band photoemission spectoscopy"Phys. Rev. B. (印刷中).

[Publications] T.Ito, et al.: "Electronic structure of black SmS : II Angle-resolved photoemission spectroscopy"Phys. Rev. B. (印刷中).

[Publications] T.Ito, et al.: "Ultrahigh-resolution photoemission spectroscopy on UGe_2"J. Phys. Soc. Jpn.. (印刷中).

[Publications] Y.Nemoto, et al.: "Low-temperature behavior of the elastic constant C44 in CexLa1-xB_6"Physica B. (印刷中).

[Publications] S.Nakamura, et al.: "Anisotropy in the magnetic phase diagrams of CexLa1-xB_6"J. Phys. Soc. Jpn.. (印刷中).

[Publications] M.Akatsu, et al.: "Thermal expansion measurements on Ce0.75La0.25B_6"J. Phys. Soc. Jpn.. (印刷中).

[Publications] T.Yamamizu, et al.: "Magnetic Phase Diagram of Ce_3Pd_<20>Ge_6 under Uniaxal Pressure"Physica B. (印刷中).

[Publications] N.Tateiwa, et al.: "Neutron Scattering Experiment on U_3Pd_<20>Si_6 II : Crystalline Electric Field and Spin Wave Excitations and Magnetic Structures"Physica B. (印刷中).

青木晴善東北大学, 極低温科学センター, 教授 (60302246)

[Publications] 松村武: "共鳴X線散乱によるDyB2C2における反強的四重極子秩序の観測"放射光. 15. 3-11 (2002)