1989 年度実績報告書

磁気共鳴手段によるフラストレ-ション状態下のスピンの動的挙動の解明

研究課題

研究課題/領域番号	63540248
研究機関	京都大学
研究代表者	網代芳民京都大学, 理学部, 助手 (00025438)
キーワード	三角格子反強磁性体 / 磁気相転移 / スピンフラストレ-ション / 磁壁ソリトン / 部分無秩序相 / カイラル転移
研究概要	本研究はスピンフラストレ-ション効果を有する最も単純な系である三角格子板反強磁性体を対象に、三角格子系のエネルギ-縮退に伴う揺らぎ効果の究明と新しい秩序相の発見を目的とする。磁気秩序化過程においてフラストレ-ションを反映した新しい秩序変数の出現が期待されたので、核磁気共鳴・電子スピン共鳴・中性子散乱・光学測定・高磁場磁化など多様な実験手段を駆使した研究を前年度にひき続いて実施し、以下の成果を得た。 1.擬一次元性が強い六方晶ABX_3型化合物を対象にして、磁気鎖間のフラストレ-ションに由来するΔAF系の秩序化現象の特異性を解明した。具体的には、イジング異方性を持つCsCOCl_3については、磁壁ソリトンによるスピンの縦成分のゆらぎの微視的解明を行い、特異な部分無秩序相がソリトン伝達による部分格子磁化反転機構から生じることを示した。ハイゼンベルグ+弱いイジング異方性を持つCsNiCl_3、CsMnI_3については、二段階逐次相転移過程におけるスピンの縦横成分の独立した秩序化の動的挙動を解明し、XY異方性を持つCsMmBr_3については、横成分スピンの秩序化に伴うカイラリティ対称性を反映した新しいユニバ-サリティを示す相転移の存在を、種々の臨界指数の精密測定によって初めて検証し、更に上記の類似化合物CsMnI_3との比較実験によって確認した。 2.より理想的な二次元△AFモデル物質系の探索を目的としてABO_2型およびAM(XO_4)_2型化合物の研究に着手し、古典スピンハイゼンベルグ△AFに特徴的な磁気励起を反映したESR線幅の温度変化、中性子散乱による二次元短距離秩序の直接観測、高磁場磁化測定による△AF特有の1/3プラト-を持つ中間状態の観測に成功した。

研究成果
(28件)

すべてその他

すべて文献書誌 (28件)

[文献書誌] H.Kikuchi: "ESR Evidence for a Drastic Difference of Spin Dynamics between Superconducting and NonーSuperconducting(La_<1-x>Ba_2)_2CuO_y" J.Phys.Soc.Japan. 57. 2628-2631 (1988)
[文献書誌] M,Chiba: "Nuclear SpinーLattice Relaxation Mechanism of SingletーGroundーState Magnet with Exchange Cupling:Application toCsFeCl _3" J,Phys.Soc.Japan. 57. 3178-3187 (1988)
[文献書誌] H.Yamazaki: "FMR of Mn/Sb Multilayered Films with Artifical Superstructure" J.Phys.Soc.Japan. 57. 4343-4350 (1988)
[文献書誌] H.Kikuchi: "NMR Study of NonーMagnetic Impurity Effect on the Spin Frustration in CsCoCl_3" J.Phys.Soc.Japan. 58. 43-46 (1989)
[文献書誌] Y.Ajiro: "Nuclear SpinーLattice Relaxation due to Domain Wall Solitons in CsCoCl_3" J.Phys.Soc.Japan. 58. 390-393 (1989)
[文献書誌] H.Kikuchi: "NMR Study of Unusual Magnetic Ordering in the Frustrated Ising Antiferromagnet,CsCoCl_3J.Phys.Soc.Japan" 58. 1989. (692-702)
[文献書誌] S.Maegawa: "^<133>Cs NMR in a Triangular Lattice Antiferromagnet CsNiCl_3" J.Phys.Soc.Japan. 57. 1402-1411 (1988)
[文献書誌] K.Amaya: "Anomalous Magnetization of RbFeCl_3 in Pulsed High Magnetic Fields" J.Phys.Soc.Japan. 57. 38-41 (1988)
[文献書誌] H.Kikuchi: "Gd^<3+> EPR of High Temperature Superconductor GdBa_2Cu_3O_x" J.Phys.Soc.Japan. 57. 1887-1890 (1988)
[文献書誌] Y.Ajiro: "Z_2 VortexーInduced Broadening of the EPR Linewidth in 2D Triangular Lattice Antiferromagnets,HCrO_2 and LiCrO_2" J.Phys.Soc.Japan. 57. 2268-2271 (1988)
[文献書誌] Y.Ajiro: "New Critical Exponent B of the XY Antiferromagnet on Stacked Triangular Lattice,CsMnBr_3" J.Phys.Soc.Japan. 57. 2648-2650 (1988)
[文献書誌] H.Kadowaki: "New Universality Class of Antiferromagnetic Phase Transition in CsMnBr_3" J.Phys.Soc.Japan. 57. 2640-2643 (1988)
[文献書誌] Y.Ajiro: "High Field Magnetization of SingletーGroundーState System Cs_3Cr_2X_9(X=Cl,Br)up to 40 T" J.Phys.Soc.Japan. 58. 1021-1026 (1989)
[文献書誌] S.Takeyama: "Magnetisation Measurements in Ultraーhigh Magnetic Fields Produced by a SingleーTurn Coil System" J.Phys.E. 21. 1025-1028 (1988)
[文献書誌] Y.Ajiro: "Evidence for Z_2 Vortex Excitations in the QuasiーTwoーDimensional Triangular Lattice Antiferromagnets,HCrO_2 nd LiCrO_2" Proc.2nd Yukawa International Seminar,Kyoto(1988)“Cooperative Dynamics in Complex Physical Systems",SpringerーVerlag. 36-37 (1989)
[文献書誌] H.Kikuchi: "SolitonーMediated Phase Transition in CsCoCl_3" Proc.2nd Yukawa International Seminar,Kyoto(1988)“Cooperative Dynamics in Complex Physical Systems",SpringerーVerlag. 40-42 (1989)
[文献書誌] H.Kikuchi: "ESR Study of Magnetic Ordering in the Frustrated Isingーlike Antiferromagnet,CsCoCl_3" J.Phys.Soc.Japan. 58. 2531-2546 (1989)
[文献書誌] I.Mogi: "Optical Investigation of Soliton in the 1D Isingーlike Antiferromagent CsCoCl_3 II" J.Phys.Soc.Japan. 58. 2188-2191 (1989)
[文献書誌] Y.Katayama: "PhotoーInduced Phenomena in Isolated Selenium Chains" J.Phys.Soc.Japan. 58. 1811-1822 (1989)
[文献書誌] M.Chiba: "New Model of SingletーGround State Magnet with Exchange Coupling Application to SeFeCl_3" J.de Phys.C8ー49. 1445-1446 (1989)
[文献書誌] H.Hori: "SpinーCluster Associated Optical Transition and Magnetization in CsCoCl_3 Under High Magnetic Fields" J.de Phys.C8ー49. 1455-1456 (1989)
[文献書誌] T.Yamazaki: "Ferromagnetic Resonance of Fe/Mg Multilayered Films with Artificial Superstructure" J.Phys.Soc.Japan. 58. 3339-3346 (1989)
[文献書誌] H.Kadowaki: "Neutron Powder Diffraction Study of TwoーDimensional Triangular Lattice Antiferromagnet CuCrO_2" J.Phys.C. (1990)
[文献書誌] Y.Ajiro: "Magnetic Phase Transition of the Triangular Lattice Antiferro magnet,CsMnI_3" J.Phys.Soc.Japan. 59. (1990)
[文献書誌] Y.Ajiro: "HighーField Magnetization of a QuasiーOneーDimensional S=1 Antiferromagnet Ni(C_2H_8N_2)_2NO_2(ClO_4):The Haldane Gap System" Phys.Rev.Lett.63. 1424-1427 (1989)
[文献書誌] K.Amaya: "High Field Magnetization of Quasi One Dimensional Ising Antiferromagnet CsCoCl_3" J.Phys.Soc.Japan. 59. (1990)
[文献書誌] T.Inami: "Magnetic Propertied of the New Triangular Lattice Antiferromagnets,CsFe(So_4)_2 and KFe(MoO_4)_2" J.Phys.Soc.Japan. 59. (1990)
[文献書誌] Y.Ajiro: "Magnetization Process of the OneーDimensional Ising Antiferromagnet with Nonmagnetic Impurity,CsCo_<1ーX>Mg_XCl_3" Phys.Rev.Lett.(1990)

1989 年度 実績報告書

磁気共鳴手段によるフラストレ-ション状態下のスピンの動的挙動の解明

研究代表者

網代 芳民 京都大学, 理学部, 助手 (00025438)

研究成果

[文献書誌] H.Kikuchi: "ESR Evidence for a Drastic Difference of Spin Dynamics between Superconducting and NonーSuperconducting(La_<1-x>Ba_2)_2CuO_y" J.Phys.Soc.Japan. 57. 2628-2631 (1988)

[文献書誌] M,Chiba: "Nuclear SpinーLattice Relaxation Mechanism of SingletーGroundーState Magnet with Exchange Cupling:Application toCsFeCl _3" J,Phys.Soc.Japan. 57. 3178-3187 (1988)

[文献書誌] H.Yamazaki: "FMR of Mn/Sb Multilayered Films with Artifical Superstructure" J.Phys.Soc.Japan. 57. 4343-4350 (1988)

[文献書誌] H.Kikuchi: "NMR Study of NonーMagnetic Impurity Effect on the Spin Frustration in CsCoCl_3" J.Phys.Soc.Japan. 58. 43-46 (1989)

[文献書誌] Y.Ajiro: "Nuclear SpinーLattice Relaxation due to Domain Wall Solitons in CsCoCl_3" J.Phys.Soc.Japan. 58. 390-393 (1989)

[文献書誌] H.Kikuchi: "NMR Study of Unusual Magnetic Ordering in the Frustrated Ising Antiferromagnet,CsCoCl_3J.Phys.Soc.Japan" 58. 1989. (692-702)

[文献書誌] S.Maegawa: "^<133>Cs NMR in a Triangular Lattice Antiferromagnet CsNiCl_3" J.Phys.Soc.Japan. 57. 1402-1411 (1988)

[文献書誌] K.Amaya: "Anomalous Magnetization of RbFeCl_3 in Pulsed High Magnetic Fields" J.Phys.Soc.Japan. 57. 38-41 (1988)

[文献書誌] H.Kikuchi: "Gd^<3+> EPR of High Temperature Superconductor GdBa_2Cu_3O_x" J.Phys.Soc.Japan. 57. 1887-1890 (1988)

[文献書誌] Y.Ajiro: "Z_2 VortexーInduced Broadening of the EPR Linewidth in 2D Triangular Lattice Antiferromagnets,HCrO_2 and LiCrO_2" J.Phys.Soc.Japan. 57. 2268-2271 (1988)

[文献書誌] Y.Ajiro: "New Critical Exponent B of the XY Antiferromagnet on Stacked Triangular Lattice,CsMnBr_3" J.Phys.Soc.Japan. 57. 2648-2650 (1988)

[文献書誌] H.Kadowaki: "New Universality Class of Antiferromagnetic Phase Transition in CsMnBr_3" J.Phys.Soc.Japan. 57. 2640-2643 (1988)

[文献書誌] Y.Ajiro: "High Field Magnetization of SingletーGroundーState System Cs_3Cr_2X_9(X=Cl,Br)up to 40 T" J.Phys.Soc.Japan. 58. 1021-1026 (1989)

[文献書誌] S.Takeyama: "Magnetisation Measurements in Ultraーhigh Magnetic Fields Produced by a SingleーTurn Coil System" J.Phys.E. 21. 1025-1028 (1988)

[文献書誌] Y.Ajiro: "Evidence for Z_2 Vortex Excitations in the QuasiーTwoーDimensional Triangular Lattice Antiferromagnets,HCrO_2 nd LiCrO_2" Proc.2nd Yukawa International Seminar,Kyoto(1988)“Cooperative Dynamics in Complex Physical Systems",SpringerーVerlag. 36-37 (1989)

[文献書誌] H.Kikuchi: "SolitonーMediated Phase Transition in CsCoCl_3" Proc.2nd Yukawa International Seminar,Kyoto(1988)“Cooperative Dynamics in Complex Physical Systems",SpringerーVerlag. 40-42 (1989)

[文献書誌] H.Kikuchi: "ESR Study of Magnetic Ordering in the Frustrated Isingーlike Antiferromagnet,CsCoCl_3" J.Phys.Soc.Japan. 58. 2531-2546 (1989)

[文献書誌] I.Mogi: "Optical Investigation of Soliton in the 1D Isingーlike Antiferromagent CsCoCl_3 II" J.Phys.Soc.Japan. 58. 2188-2191 (1989)

[文献書誌] Y.Katayama: "PhotoーInduced Phenomena in Isolated Selenium Chains" J.Phys.Soc.Japan. 58. 1811-1822 (1989)

[文献書誌] M.Chiba: "New Model of SingletーGround State Magnet with Exchange Coupling Application to SeFeCl_3" J.de Phys.C8ー49. 1445-1446 (1989)

[文献書誌] H.Hori: "SpinーCluster Associated Optical Transition and Magnetization in CsCoCl_3 Under High Magnetic Fields" J.de Phys.C8ー49. 1455-1456 (1989)

[文献書誌] T.Yamazaki: "Ferromagnetic Resonance of Fe/Mg Multilayered Films with Artificial Superstructure" J.Phys.Soc.Japan. 58. 3339-3346 (1989)

[文献書誌] H.Kadowaki: "Neutron Powder Diffraction Study of TwoーDimensional Triangular Lattice Antiferromagnet CuCrO_2" J.Phys.C. (1990)

[文献書誌] Y.Ajiro: "Magnetic Phase Transition of the Triangular Lattice Antiferro magnet,CsMnI_3" J.Phys.Soc.Japan. 59. (1990)

[文献書誌] Y.Ajiro: "HighーField Magnetization of a QuasiーOneーDimensional S=1 Antiferromagnet Ni(C_2H_8N_2)_2NO_2(ClO_4):The Haldane Gap System" Phys.Rev.Lett.63. 1424-1427 (1989)

[文献書誌] K.Amaya: "High Field Magnetization of Quasi One Dimensional Ising Antiferromagnet CsCoCl_3" J.Phys.Soc.Japan. 59. (1990)

[文献書誌] T.Inami: "Magnetic Propertied of the New Triangular Lattice Antiferromagnets,CsFe(So_4)_2 and KFe(MoO_4)_2" J.Phys.Soc.Japan. 59. (1990)

[文献書誌] Y.Ajiro: "Magnetization Process of the OneーDimensional Ising Antiferromagnet with Nonmagnetic Impurity,CsCo_<1ーX>Mg_XCl_3" Phys.Rev.Lett.(1990)

1989 年度実績報告書

網代芳民京都大学, 理学部, 助手 (00025438)