2002 年度実績報告書

Prスクッテルダイト化合物における重い電子状態の究明

研究課題

研究課題/領域番号	13640369
研究機関	東京都立大学
研究代表者	青木勇二東京都立大学, 理学研究科, 助手 (20231772)
キーワード	強相関電子系 / 重い電子状態 / 充填スクッテルダイト / 比熱 / 重い電子超伝導体 / 四極子秩序 / 異方的超伝導 / muSR法
研究概要	1.PrOs_4Sb_<12>がPr化合物としては初めての重い電子超伝導体であることが2002年に見出された。早速、単結晶試料を用いて本系の研究をスタートした。 (1)超伝導相の基本物性を比熱測定により調べた。超伝導転移に二段の異常が存在することを確認し、その磁場温度相図を明らかにした。比熱のとびの磁場依存から、熱力学的関係式を利用して、超伝導相の磁場による破壊の特徴を調べた。超伝導対称性の特徴をつかむためのmuSR法による測定も開始した。 (2)超伝導発現の背景にある常伝導相の物性についても比熱を中心に調べた。その異常な側面が明らかとなって来た。約4テスラ以上の高磁場下で、磁場誘起の秩序相が存在していることを、比熱測定により見出した。この相は、さらに高磁場側(約14テスラ以上)で消失する。量子振動(dHvA効果)測定から、この高磁場領域では、Prイオンの4f電子は比較的よく局在していることが示唆されていることをふまえ、可能な結晶場モデルを絞り込んだ。一重項基底状態と磁気的三重項励起状態の組合わせが、現時点では、もっとも合理的に各種物理量を説明することと、このモデルに基づきながら、磁場中で期待される準位交差近傍での四極子自由度の凍結が、この磁場誘起秩序相の起源であることを主張した。その後、秩序相内で中性子散乱実験を行い、観測された磁気構造が、上記のモデルでうまく記述できることを示した。このことは、四極子自由度の揺らぎが超伝導の背景に存在し、この揺らぎが、この系での重い準粒子形成や、クーパー対形成に重要な役割を果している可能性を強く示唆している。

研究成果

(30件)

すべてその他

すべて文献書誌 (30件)

[文献書誌] Y.Aoki: "Nonmagnetic ordered state in heavy electron PrFe4P12 evidenced by specific heat"Physica B. 312-313. 823-824 (2002)
[文献書誌] T.Namiki: "La-substitution study on filled skutterudite PrFe_4P_<12>"Physica B. 312-313. 825-826 (2002)
[文献書誌] K.Abe: "Unusual behaviors in the heavy Fermion semimetal CeRu4Sb12"Physica B. 312-313. 256-258 (2002)
[文献書誌] K.Iwasa: "Crystal-Structure Modulation in the Anomalous Low-Temperature Phase of PrFe4P12"Physica B. 312-313. 834-836 (2002)
[文献書誌] H.Sugawara: "De Haas-van Alphen Effect in the Filled Skutterudite CeRu4Sb12"Physica B. 312-313. 264-266 (2002)
[文献書誌] T.D.Matsuda: "De Haas-van Alphen Effect on PrRu_4Sb_<12>"Physica B. 312-313. 832-833 (2002)
[文献書誌] T.D.Matsuda: "Effect of uniaxial pressure on the magnetic properties in PrFe_4P_<12>"J. Phys. Soc. Jpn. Suppl.. 71. 246-248 (2002)
[文献書誌] Y.Aoki: "Anomalous ordered phase in 4f^2-based heavy electron PrFe_4P_<12>"J. Phys. Chem. Sol.. 63. 1201-1205 (2002)
[文献書誌] Y.Aoki: "Thermodynamical Study on the Heavy-Fermion Superconductor PrOs_4Sb_<12> : Evidence for Field-Induced Phase Transition"J. Phys. Soc. Jpn.. 71. 2098-2101 (2002)
[文献書誌] H.Sugawara: "Exotic heavy fermion state in the filled skutterudite PrFe_4P_<12> uncovered by the de Haas van aAlphen effect"Phys. Rev. B. 66. 134411 (2002)
[文献書誌] H.Sugawara: "Fermi surface of the heavy-fermion superconductor PrOs_4Sb_<12>"Phys. Rev. B. 66. 220504(R) (2002)
[文献書誌] H.Kotegawa: "Evidence for Unconventional Strong-Coupling Superconductivity in PrOs_4Sb_<12> : An Sb Nuclear Quadrupole Resonance Study"Phys. Rev. Lett.. 90. 027001 (2003)
[文献書誌] K.Abe: "Transport properties in the filled-skutterudite compounds RERu_4Sb_<12> (RE-La,Ce,Pr and Nd) ; an exotic heavy fermion semimetal CeRu_4Sb_<12>"J. Phys., Condens. Matter.. 14. 11757-11768 (2002)
[文献書誌] H.Sato: "Transport and thermal properties of Ce-and Pr-filled skutterudites"Physica B. 328. 34-38 (2003)
[文献書誌] Y.Aoki: "Specific Heat Study on Heavy-Fermion Pr compounds with filled skutterudite structure"Acta Phys. Polonica B. 34・2. 1145-1148 (2003)
[文献書誌] T.Namiki: "Anomalous ordered state of filled skutterudite CeOs_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1161-1164 (2003)
[文献書誌] L.Hao: "Antiferro-quadrupolar Ordering of 4f-electron State in the Filled Skutterudite PrFe_4P_<12>"Acta Phys. Polonica B. 34・2. 1113-1116 (2003)
[文献書誌] K.Iwasa: "Magnetic excitations in the heavy-electron and antiferro-quadrupolar-ordering system PrFe_4P_<12>"Acta Phys. Polonica B. 34・2. 1117-1120 (2003)
[文献書誌] E.Kuramochi: "Magnetic field effect on the transport properties of the anomalous heavy fermion PrFe_4P_<12>"Acta Phys. Polonica B. 34・2. 1129-1132 (2003)
[文献書誌] H.Sugawara: "de Haas-van Alphen effect in heavy fermion superconductor PrOs_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1125-1128 (2003)
[文献書誌] S.R.Saha: "Uniaxial pressure effect on the SdH oscillations in heavv-fermion semimetal CeRu_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1137-1140 (2003)
[文献書誌] E.Bauer: "Non-Fermi-liquid features of novel Yb_2Pd_2In"Acta Phys. Polonica B. 34・2. 367-370 (2003)
[文献書誌] H.Kotegawa: "Unusual Superconductivity in Skutterudite Compound PrOs_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1003-1006 (2003)
[文献書誌] H.Sato: "Anomalous transport properties in the filled skutterudites"J. Magn. Magn. Mat.. 258-259. 67-72 (2003)
[文献書誌] Y.Aoki: "Specific heat study on the anomalous normal state of heavy-fermion superconductor PrOs_4Sb_<12>"Physica C. (未定). (2003)
[文献書誌] K.Ishii: "Resonant X-ray scattering study on the filled skutterudite PrFe_4P_<12>"Physica B. (未定). (2003)
[文献書誌] T.Namiki: "Magnetic anisotropy of the heavy fermion state in PrFe_4P_<12>"Physica B. (未定). (2003)
[文献書誌] H.Sugawara: "High field magnetoresistance in heavy fermion superconductor PrOs_4Sb_<12>"Physica B. (未定). (2003)
[文献書誌] M.Kobayashi: "Pressure effect on the transport properties in heavy-fermion semimetal CeRu_4Sb_<12>"Physica B. (未定). (2003)
[文献書誌] Masahumi Kohgi: "Evidence for Magnetic-field-induced Quadrupolar Ordering in the Heavy Fermion Superconductor PrOs_4Sb_<12> : Evidence for Field-Induced Phase Transition"J. Phys. Soc. Jpn.. 71・5月号(未定). (2003)

2002 年度 実績報告書

Prスクッテルダイト化合物における重い電子状態の究明

研究代表者

青木 勇二 東京都立大学, 理学研究科, 助手 (20231772)

研究成果

[文献書誌] Y.Aoki: "Nonmagnetic ordered state in heavy electron PrFe4P12 evidenced by specific heat"Physica B. 312-313. 823-824 (2002)

[文献書誌] T.Namiki: "La-substitution study on filled skutterudite PrFe_4P_<12>"Physica B. 312-313. 825-826 (2002)

[文献書誌] K.Abe: "Unusual behaviors in the heavy Fermion semimetal CeRu4Sb12"Physica B. 312-313. 256-258 (2002)

[文献書誌] K.Iwasa: "Crystal-Structure Modulation in the Anomalous Low-Temperature Phase of PrFe4P12"Physica B. 312-313. 834-836 (2002)

[文献書誌] H.Sugawara: "De Haas-van Alphen Effect in the Filled Skutterudite CeRu4Sb12"Physica B. 312-313. 264-266 (2002)

[文献書誌] T.D.Matsuda: "De Haas-van Alphen Effect on PrRu_4Sb_<12>"Physica B. 312-313. 832-833 (2002)

[文献書誌] T.D.Matsuda: "Effect of uniaxial pressure on the magnetic properties in PrFe_4P_<12>"J. Phys. Soc. Jpn. Suppl.. 71. 246-248 (2002)

[文献書誌] Y.Aoki: "Anomalous ordered phase in 4f^2-based heavy electron PrFe_4P_<12>"J. Phys. Chem. Sol.. 63. 1201-1205 (2002)

[文献書誌] Y.Aoki: "Thermodynamical Study on the Heavy-Fermion Superconductor PrOs_4Sb_<12> : Evidence for Field-Induced Phase Transition"J. Phys. Soc. Jpn.. 71. 2098-2101 (2002)

[文献書誌] H.Sugawara: "Exotic heavy fermion state in the filled skutterudite PrFe_4P_<12> uncovered by the de Haas van aAlphen effect"Phys. Rev. B. 66. 134411 (2002)

[文献書誌] H.Sugawara: "Fermi surface of the heavy-fermion superconductor PrOs_4Sb_<12>"Phys. Rev. B. 66. 220504(R) (2002)

[文献書誌] H.Kotegawa: "Evidence for Unconventional Strong-Coupling Superconductivity in PrOs_4Sb_<12> : An Sb Nuclear Quadrupole Resonance Study"Phys. Rev. Lett.. 90. 027001 (2003)

[文献書誌] K.Abe: "Transport properties in the filled-skutterudite compounds RERu_4Sb_<12> (RE-La,Ce,Pr and Nd) ; an exotic heavy fermion semimetal CeRu_4Sb_<12>"J. Phys., Condens. Matter.. 14. 11757-11768 (2002)

[文献書誌] H.Sato: "Transport and thermal properties of Ce-and Pr-filled skutterudites"Physica B. 328. 34-38 (2003)

[文献書誌] Y.Aoki: "Specific Heat Study on Heavy-Fermion Pr compounds with filled skutterudite structure"Acta Phys. Polonica B. 34・2. 1145-1148 (2003)

[文献書誌] T.Namiki: "Anomalous ordered state of filled skutterudite CeOs_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1161-1164 (2003)

[文献書誌] L.Hao: "Antiferro-quadrupolar Ordering of 4f-electron State in the Filled Skutterudite PrFe_4P_<12>"Acta Phys. Polonica B. 34・2. 1113-1116 (2003)

[文献書誌] K.Iwasa: "Magnetic excitations in the heavy-electron and antiferro-quadrupolar-ordering system PrFe_4P_<12>"Acta Phys. Polonica B. 34・2. 1117-1120 (2003)

[文献書誌] E.Kuramochi: "Magnetic field effect on the transport properties of the anomalous heavy fermion PrFe_4P_<12>"Acta Phys. Polonica B. 34・2. 1129-1132 (2003)

[文献書誌] H.Sugawara: "de Haas-van Alphen effect in heavy fermion superconductor PrOs_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1125-1128 (2003)

[文献書誌] S.R.Saha: "Uniaxial pressure effect on the SdH oscillations in heavv-fermion semimetal CeRu_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1137-1140 (2003)

[文献書誌] E.Bauer: "Non-Fermi-liquid features of novel Yb_2Pd_2In"Acta Phys. Polonica B. 34・2. 367-370 (2003)

[文献書誌] H.Kotegawa: "Unusual Superconductivity in Skutterudite Compound PrOs_4Sb_<12>"Acta Phys. Polonica B. 34・2. 1003-1006 (2003)

[文献書誌] H.Sato: "Anomalous transport properties in the filled skutterudites"J. Magn. Magn. Mat.. 258-259. 67-72 (2003)

[文献書誌] Y.Aoki: "Specific heat study on the anomalous normal state of heavy-fermion superconductor PrOs_4Sb_<12>"Physica C. (未定). (2003)

[文献書誌] K.Ishii: "Resonant X-ray scattering study on the filled skutterudite PrFe_4P_<12>"Physica B. (未定). (2003)

[文献書誌] T.Namiki: "Magnetic anisotropy of the heavy fermion state in PrFe_4P_<12>"Physica B. (未定). (2003)

[文献書誌] H.Sugawara: "High field magnetoresistance in heavy fermion superconductor PrOs_4Sb_<12>"Physica B. (未定). (2003)

[文献書誌] M.Kobayashi: "Pressure effect on the transport properties in heavy-fermion semimetal CeRu_4Sb_<12>"Physica B. (未定). (2003)

[文献書誌] Masahumi Kohgi: "Evidence for Magnetic-field-induced Quadrupolar Ordering in the Heavy Fermion Superconductor PrOs_4Sb_<12> : Evidence for Field-Induced Phase Transition"J. Phys. Soc. Jpn.. 71・5月号(未定). (2003)

2002 年度実績報告書

青木勇二東京都立大学, 理学研究科, 助手 (20231772)