2000 Fiscal Year Annual Research Report

巨大磁気抵抗酸化物における軌道秩序の磁気分光

Research Project

Project/Area Number	12440095
Research Institution	The University of Tokyo
Principal Investigator	十倉好紀東京大学, 大学院・工学系研究科, 教授 (30143382)
Co-Investigator(Kenkyū-buntansha)	田口康二郎東京大学, 大学院・工学系研究科, 助手 (70301132) 木村剛東京大学, 大学院・工学系研究科, 講師 (80323525)
Keywords	巨大磁気抵抗 / 軌道秩序 / 協力的ヤーンテーラー変形 / A型反強磁性 / 電荷移動型 / 軌道波 / 磁場中反射分光 / 磁場中ラマン分光
Research Abstract	本年度は、巨大磁気抵抗効果を示すマンガン酸化物の母体であり、また軌道秩序を示す典型物質であるLaMnO_3のシングルドメインの結晶を作成することに成功し、光学スペクトルの測定によってその電子構造の異方性を明らかにした。LaMnO_3は770K付近で協力的ヤーンテーラー変形を伴った軌道整列相転移を示し、さらに140K付近でA型の反強磁性相へと転移する。多くの理論計算は、A型の反強磁性秩序によって電子構造の異方性が生じることを予言しているが、低温で観測された大きな異方性は温度の上昇とともに緩やかに減少し、反強磁性転移点では大きな影響を受けず、むしろ、軌道整列転移点で急激に消失することが明らかになった。このことは、軌道秩序が電子構造に与える影響の重要性を示しており、また、この結果からLaMnO_3の最低電荷励起はモット型ではなく電荷移動型であることが結論される。さらに、この典型的な軌道整列系において軌道の集団励起に対応する軌道波をラマン散乱によって観測することに初めて成功した。100meV以上の高いエネルギー位置に観測されたラマンバンドは、その偏光依存性や散乱強度など理論的な予測と一致し、それが軌道波であることが確認された。一方で、磁場中でのスペクトロスコピー用の実験系の立ち上げを行い、超伝導磁石を用いた反射分光、ラマン分光を行うための測定系を整備した。これにより、来年度に向けて磁場中での反射分光、ラマン分光測定によって、巨大磁気抵抗と軌道秩序の相関を明らかにし、また、軌道波に対する磁場の影響などを明らかにすることができる。

Research Products
(39 results)

All Other

All Publications (39 results)

[Publications] P.Dai: "Magnon damping by magnon-phonon coupling in manganese perovskites"Phys.Rev.B. 61. 9553-9557 (2000)
[Publications] S.H.Chun: "Breakdown of the lattice polaron picture in La_<0.7>Ca_<0.3>MnO_3 single crystals"Phys.Rev.B. 61. R9225-R9228 (2000)
[Publications] R.D.Merithew: "Mesoscopic Thermodynamics of an Inhomogeneous Colossal-Magnetoresistive Phase"Phys.Rev.Lett. 84. 3442-3445 (2000)
[Publications] S.Horiuchi: "Anomalous Valence Fluctuation Near a Ferroelectric Transition in an Organic Cha〓 Transfer Complex"J.Phys.Soc.Jpn.. 69. 1302-1305 (2000)
[Publications] M.Izumi: "La_<1-x>Sr_xMnO_3 superlattices composed of ferromagnetic x=0.4 and antiferromagnetic x=0.55 layers"Phys.Rev.B. 12187-12195 (2000)
[Publications] P.Lin: "Magnetic heat capacity in lanthanum manganite single crystals"J.Appl.Phys.. 87. 5825-5827 (2000)
[Publications] K.Yamamoto: "Raman spectroscopy of the charge-orbital ordering in layered manganites"Phys.Rev.B. 61. 14706-14715 (2000)
[Publications] Y.Kawabe: "Photoluminescence of perovskite lanthanum aluminate single crystals"J.Appl.Phys.. 88. 1175-1177 (2000)
[Publications] M.Satake: "Charge ordering and chemical potential shift in La_<2-x>Sr_xNiO_4 studied by photoemission spectroscopy"Phys.Rev.B. 61. 15515-15518 (2000)
[Publications] H.Kishida: "Gigantic optical nonlinearity in one-dimensional Mott-Hubbard insulators"Nature. 405. 929-932 (2000)
[Publications] T.Saitoh: "Temperature-deperndernt pseudogaps in colossal magnetoresistive oxides"Phys.Rev.B. 62. 1039-1043 (2000)
[Publications] K.-I.Kobayashi: "Possible percolation and magnetoresistance in ordered double perovskite alloys Sr_2(W_<1-x>Mo_x)O_6"J.Mag.Mag.Mat.. 218. 17-24 (2000)
[Publications] E.Saitoh: "Directional ordering and collective fluctuation of orbital in a colossal magnetoresistive manganite"J.Phys.Soc.Jpn.. 69. 2403-2406 (2000)
[Publications] S.Shimomura: "X-ray diffuse scattering study on charge-localized states of Pr_<1-x>Ca_xMnO_3 (x=0.35,0.4,0.5)"Phys.Rev.B. 62. 3875-3878 (2000)
[Publications] R.Matzdorf: "Ferromagnetism Stabilized by Lattice Distortion at the Surface of the p-Wave Super-conductor Sr_2RuO_4"Science. 289. 746-748 (2000)
[Publications] T.Kise: "Ultrafast Spin Dynamics and Critical Behavior in Half-Metallic Ferromagn〓 Sr_2FeMoO_6"Phys.Rev.Lett.. 85. 1986-1989 (2000)
[Publications] Y.Taguchi: "Dielectric breakdown of one-dimensional Mott insulators Sr_2CuO_3 and SrCuO_2"Phys.Rev.B. 62. 7015-7018 (2000)
[Publications] P.Dai: "Short-Range Polaron Correlations in the Ferromagnetic La_<1-x>Ca_xMnO_3"Phys.Rev.Lett.. 85. 2553-2556 (2000)
[Publications] T.Katsufuji: "Coexistence of two components in the optical spectra of CeTiO_<3.04> in the antiferromagnetic metallic phase"Phys.Rev.B. 62. 10797-10801 (2000)
[Publications] H.Tachibana: "Photoluminescence from pendant dye molecules mediated by exciton transport on helical polysilane chains"Appl.Phys.Lett.. 77. 2443-2445 (2000)
[Publications] B.Keimer: "Spin Dynamics and Orbital State in LaTiO_3"Phys.Rev.Lett.. 85. 3946-3949 (2000)
[Publications] T.Saito: "Optical Study of Metal-Insulator Transition in SmBaCo_2O_<6-δ> Single Crystal"J.Phys.Soc.Jpn.. 69. 3525-3528 (2000)
[Publications] E.Saitoh: "Optical Study of Metal-Insulator Transition in the Ferromagnetic Ground State of La_<1-x>Sr_xMnO_3"J.Phys.Soc.Jpn.. 69. 3614-3620 (2000)
[Publications] T.Ishikawa: "Optical study on the doping and temperature dependence of the anisotropic electronic structure in bilayered manganites : La_<2-2x>Sr_<1+2x>Mn_2O_7 (0.3<x<0.5)"Phys.Rev.B. 62. 12354-12362 (2000)
[Publications] T.Fukumura: "Rapid construction of a phase diagram of doped Mott insulators with a composition-spread approach"Appl.Phys.Lett.. 77. 3426-3428 (2000)
[Publications] T.Tonogai: "Spectroscopic study of photoinduced charge-gap collapse in the correlated insulators Pr_<1-x>Ca_xMnO_3"Phys.Rev.B. 62. 13903-13906 (2000)
[Publications] H.Hazama: "Quadrupolar effect in the perovskite manganite La_<1-x>Sr_xMnO_3"Phys.Rev.B. 62. 15012-15020 (2000)
[Publications] T.Kimura: "Variation of charge-orbital correlation with Cr doping in manganites"Phys.Rev.B. 62. 15201-15025 (2000)
[Publications] A.Damascelli: "Fermi Surface, Surface States, and Surface Reconstruction in Sr_2RuO_4"Phys.Rev.Lett.. 85. 5194-5197 (2000)
[Publications] S.Horiuchi: "Neutral-Ionic Phase Separation and One-Dimensional Ferroelectricity in Organic Relaxors"Phys.Rev.Lett.. 85. 5210-5213 (2000)
[Publications] S.Miyasaka: "Critical Behavior of Metal-Insulator Transition in La_<1-x>Sr_xVO_3"Phys.Rev.Lett.. 85. 5388-5391 (2000)
[Publications] H.Tachibana: "Crystal structures, polymerization, and thermochromic phase changes in urethane-substituted diacetylenes crystals with varying alkyl chain lengths"Chem.Mater.. 13. 155-158 (2001)
[Publications] Y.Tomioka: "Magnetotransport properties and magnetostructural phenomenon in single crystals of La_<0.7>(Ca_<1-y>Sr_y)_<0.3>MnO_3"Phys.Rev.B. 63. 024421 (2001)
[Publications] X.G.Qiu: "Josephson plasma observed in underdoped (110) YBa_2Cu_3O_<7-δ> films"Appl.Phys.Lett.. 78. 506-508 (2001)
[Publications] H.Tachibana: "Highly oriented Langmuir-Blodgett films of helical polysilanes and their optical properties"Langumuir. 17. 437-440 (2001)
[Publications] S.Horiuchi: "Ferroelectric valence transition and phase diagram of a series of charge-transfer complexes of 4,4'-dimethyltetrathiafulvalene and tetrahalo-p-benzoquintones"J.Am.Chem.Soc.. 123. 665-670 (2001)
[Publications] N.P.Armitage: "Superconducting Gap Anisotropy in Nd_<1.85>Ce_<0.15>CuO_4 : Results from Photoemission"Phys.Rev.Lett.. 86. 1126-1129 (2001)
[Publications] T.Okuda: "Large thermoelectric response of metallic perovskites : Sr_<1-x>La_xTiO_3 (0<=x<=0.1)"Phys.Rev.B. 63. 113104 (2001)
[Publications] T.Ogasawara: "Dynamics of photoinduced melting of charge/orbital order in a layered manganite La_<0.5>Sr_<1.5>MnO_4"Phys.Rev.B. 63. 113105 (2001)

2000 Fiscal Year Annual Research Report

巨大磁気抵抗酸化物における軌道秩序の磁気分光

Principal Investigator

十倉 好紀 東京大学, 大学院・工学系研究科, 教授 (30143382)

Research Products

[Publications] P.Dai: "Magnon damping by magnon-phonon coupling in manganese perovskites"Phys.Rev.B. 61. 9553-9557 (2000)

[Publications] S.H.Chun: "Breakdown of the lattice polaron picture in La_<0.7>Ca_<0.3>MnO_3 single crystals"Phys.Rev.B. 61. R9225-R9228 (2000)

[Publications] R.D.Merithew: "Mesoscopic Thermodynamics of an Inhomogeneous Colossal-Magnetoresistive Phase"Phys.Rev.Lett. 84. 3442-3445 (2000)

[Publications] S.Horiuchi: "Anomalous Valence Fluctuation Near a Ferroelectric Transition in an Organic Cha〓 Transfer Complex"J.Phys.Soc.Jpn.. 69. 1302-1305 (2000)

[Publications] M.Izumi: "La_<1-x>Sr_xMnO_3 superlattices composed of ferromagnetic x=0.4 and antiferromagnetic x=0.55 layers"Phys.Rev.B. 12187-12195 (2000)

[Publications] P.Lin: "Magnetic heat capacity in lanthanum manganite single crystals"J.Appl.Phys.. 87. 5825-5827 (2000)

[Publications] K.Yamamoto: "Raman spectroscopy of the charge-orbital ordering in layered manganites"Phys.Rev.B. 61. 14706-14715 (2000)

[Publications] Y.Kawabe: "Photoluminescence of perovskite lanthanum aluminate single crystals"J.Appl.Phys.. 88. 1175-1177 (2000)

[Publications] M.Satake: "Charge ordering and chemical potential shift in La_<2-x>Sr_xNiO_4 studied by photoemission spectroscopy"Phys.Rev.B. 61. 15515-15518 (2000)

[Publications] H.Kishida: "Gigantic optical nonlinearity in one-dimensional Mott-Hubbard insulators"Nature. 405. 929-932 (2000)

[Publications] T.Saitoh: "Temperature-deperndernt pseudogaps in colossal magnetoresistive oxides"Phys.Rev.B. 62. 1039-1043 (2000)

[Publications] K.-I.Kobayashi: "Possible percolation and magnetoresistance in ordered double perovskite alloys Sr_2(W_<1-x>Mo_x)O_6"J.Mag.Mag.Mat.. 218. 17-24 (2000)

[Publications] E.Saitoh: "Directional ordering and collective fluctuation of orbital in a colossal magnetoresistive manganite"J.Phys.Soc.Jpn.. 69. 2403-2406 (2000)

[Publications] S.Shimomura: "X-ray diffuse scattering study on charge-localized states of Pr_<1-x>Ca_xMnO_3 (x=0.35,0.4,0.5)"Phys.Rev.B. 62. 3875-3878 (2000)

[Publications] R.Matzdorf: "Ferromagnetism Stabilized by Lattice Distortion at the Surface of the p-Wave Super-conductor Sr_2RuO_4"Science. 289. 746-748 (2000)

[Publications] T.Kise: "Ultrafast Spin Dynamics and Critical Behavior in Half-Metallic Ferromagn〓 Sr_2FeMoO_6"Phys.Rev.Lett.. 85. 1986-1989 (2000)

[Publications] Y.Taguchi: "Dielectric breakdown of one-dimensional Mott insulators Sr_2CuO_3 and SrCuO_2"Phys.Rev.B. 62. 7015-7018 (2000)

[Publications] P.Dai: "Short-Range Polaron Correlations in the Ferromagnetic La_<1-x>Ca_xMnO_3"Phys.Rev.Lett.. 85. 2553-2556 (2000)

[Publications] T.Katsufuji: "Coexistence of two components in the optical spectra of CeTiO_<3.04> in the antiferromagnetic metallic phase"Phys.Rev.B. 62. 10797-10801 (2000)

[Publications] H.Tachibana: "Photoluminescence from pendant dye molecules mediated by exciton transport on helical polysilane chains"Appl.Phys.Lett.. 77. 2443-2445 (2000)

[Publications] B.Keimer: "Spin Dynamics and Orbital State in LaTiO_3"Phys.Rev.Lett.. 85. 3946-3949 (2000)

[Publications] T.Saito: "Optical Study of Metal-Insulator Transition in SmBaCo_2O_<6-δ> Single Crystal"J.Phys.Soc.Jpn.. 69. 3525-3528 (2000)

[Publications] E.Saitoh: "Optical Study of Metal-Insulator Transition in the Ferromagnetic Ground State of La_<1-x>Sr_xMnO_3"J.Phys.Soc.Jpn.. 69. 3614-3620 (2000)

[Publications] T.Ishikawa: "Optical study on the doping and temperature dependence of the anisotropic electronic structure in bilayered manganites : La_<2-2x>Sr_<1+2x>Mn_2O_7 (0.3<x<0.5)"Phys.Rev.B. 62. 12354-12362 (2000)

[Publications] T.Fukumura: "Rapid construction of a phase diagram of doped Mott insulators with a composition-spread approach"Appl.Phys.Lett.. 77. 3426-3428 (2000)

[Publications] T.Tonogai: "Spectroscopic study of photoinduced charge-gap collapse in the correlated insulators Pr_<1-x>Ca_xMnO_3"Phys.Rev.B. 62. 13903-13906 (2000)

[Publications] H.Hazama: "Quadrupolar effect in the perovskite manganite La_<1-x>Sr_xMnO_3"Phys.Rev.B. 62. 15012-15020 (2000)

[Publications] T.Kimura: "Variation of charge-orbital correlation with Cr doping in manganites"Phys.Rev.B. 62. 15201-15025 (2000)

[Publications] A.Damascelli: "Fermi Surface, Surface States, and Surface Reconstruction in Sr_2RuO_4"Phys.Rev.Lett.. 85. 5194-5197 (2000)

[Publications] S.Horiuchi: "Neutral-Ionic Phase Separation and One-Dimensional Ferroelectricity in Organic Relaxors"Phys.Rev.Lett.. 85. 5210-5213 (2000)

[Publications] S.Miyasaka: "Critical Behavior of Metal-Insulator Transition in La_<1-x>Sr_xVO_3"Phys.Rev.Lett.. 85. 5388-5391 (2000)

[Publications] H.Tachibana: "Crystal structures, polymerization, and thermochromic phase changes in urethane-substituted diacetylenes crystals with varying alkyl chain lengths"Chem.Mater.. 13. 155-158 (2001)

[Publications] Y.Tomioka: "Magnetotransport properties and magnetostructural phenomenon in single crystals of La_<0.7>(Ca_<1-y>Sr_y)_<0.3>MnO_3"Phys.Rev.B. 63. 024421 (2001)

[Publications] X.G.Qiu: "Josephson plasma observed in underdoped (110) YBa_2Cu_3O_<7-δ> films"Appl.Phys.Lett.. 78. 506-508 (2001)

[Publications] H.Tachibana: "Highly oriented Langmuir-Blodgett films of helical polysilanes and their optical properties"Langumuir. 17. 437-440 (2001)

[Publications] S.Horiuchi: "Ferroelectric valence transition and phase diagram of a series of charge-transfer complexes of 4,4'-dimethyltetrathiafulvalene and tetrahalo-p-benzoquintones"J.Am.Chem.Soc.. 123. 665-670 (2001)

[Publications] N.P.Armitage: "Superconducting Gap Anisotropy in Nd_<1.85>Ce_<0.15>CuO_4 : Results from Photoemission"Phys.Rev.Lett.. 86. 1126-1129 (2001)

[Publications] T.Okuda: "Large thermoelectric response of metallic perovskites : Sr_<1-x>La_xTiO_3 (0<=x<=0.1)"Phys.Rev.B. 63. 113104 (2001)

[Publications] T.Ogasawara: "Dynamics of photoinduced melting of charge/orbital order in a layered manganite La_<0.5>Sr_<1.5>MnO_4"Phys.Rev.B. 63. 113105 (2001)

十倉好紀東京大学, 大学院・工学系研究科, 教授 (30143382)