2003 年度実績報告書

磁場が誘起するマグノンのボース・アインシュタイン凝縮と局在

研究課題

研究課題/領域番号	13130202
研究機関	東京工業大学
研究代表者	田中秀数東京工業大学, 極低温物性研究センター, 教授 (80188325)
研究分担者	細越裕子大阪府立大学, 総合科学部, 助教授 (50290903) 小野俊雄東京工業大学, 大学院・理工学研究科, 助手 (40332639) 押川正毅東京工業大学, 大学院・理工学研究科, 助教授 (50262043)
キーワード	スピンギャップ / マグノン / ボース・アインシュタイン凝縮 / ESR / 磁場誘起相転移 / 磁化プラトー / TlCuCl_3 / 有機物低次元磁性体
研究概要	科研費特定領域研究の支援の下で,本年度は以下の研究実績を上げた. 1.スピンギャップ系TlCuCl_3の磁場誘起相転移はマグノンのボース・アインシュタイン凝縮(以下ボース凝縮と略す)として理解できる.田中と小野は東北大学グループとの共同研究により,磁場誘起相転移に伴ってマグノンの熱伝導が異常に増大することを観測した.これはマグノンのボース凝縮と一致する結果である.またドイツのマックスプランク研究所グループとの共同研究でTlCuCl_3の磁場誘起相転移を超音波吸収実験で調べ,様々な温度での吸収係数の磁場依存性がマグノンのボース凝縮の観点からよく説明できることを示した.更にTlCuCl_3の低温磁場中比熱を詳細に調べ,量子臨界点近傍では相境界がマグノンのボース凝縮理論が予言する3/2に近くなることを示した.これによって磁場誘起相転移のマグノンボース凝縮描像がより確かになった. 2.TlCuCl_3の圧力誘起反強磁性転移を磁化測定で詳細に調べ,スピンギャップや相転移温度の圧力依存性を測定した.これは圧力誘起磁気量子相転移の最初の例である. 5.S=1/2の歪んだ三角格子反強磁性体Cs_2CuBr_4を開拓し,量子揺らぎによる1/3磁化プラトーを初めて発見した.また磁化プラトー状態でのスピン構造を磁場中中性子散乱で決定した.更に磁気励起を中性子非弾性燦欄で調べ,スピンの分数化と関連付けられる連続励起を観測した. 4.細越はS=1/2交互反強磁性一次元鎖化合物F5PNN, S=1とS=1/2の混合スピン系であるBIPNNBNO, S=1蜂の巣化合物F2PNNNOなどの新しい有機物低次元磁性体合成し,強磁場磁化,NMR,比熱測定によって磁場誘起相転移と量子臨界点近傍での異常な磁気物性を詳細に調べた. 5.多体系における粒子密度と格子構造の整合性の背後にはトポロジカルな量子化の機構が存在していると考えられ,磁化プラトーの量子化などとも関連して興味が持たれている.押川は今までの議論を更に発展させ,外場に対する動的な応答を定義するDrude重みの存在と整合性,基底状態の縮退度に関する一般的な関係を導いた.

研究成果

(33件)

すべてその他

すべて文献書誌 (33件)

[文献書誌] A.Oosawa: "Neutron Scattering Study of Magnetic Ordering and Excitations in the Doped Spin Gap System Tl(Cu_<1-x>Mg_x)Cl_3"Phys.Rev.B. 67. 184424-1-184424-8 (2003)
[文献書誌] T.Ono: "Magnetization Plateau in the Frustrated Quantum Spin System Cs_2CuBr_4"Phys.Rev.B. 67. 104431-1-104431-7 (2003)
[文献書誌] M.Fujisawa: "Crystal Structure and Magnetic Properties of the Quasi-One-Dimensional Quantum Spin System Cu_2Cl_4・H_8C_4SO_2"J.Phys.Soc.Jpn.. 72. 694-697 (2003)
[文献書誌] S.Hosoya: "NMR Study on the Quantum Spin Ladder NH_4CuCl_3"Physica B. 329-333. 977-978 (2003)
[文献書誌] H.Nojiri: "Coexistence of Gap-less and Gapped Excitations in NH_4 CuCl_3"Physica B. 329-333. 701-702 (2003)
[文献書誌] Y.Shimaoka: "NMR Study of Magnetic Structures in NH_4CuCl_3"Physica B. 329-333. 894-895 (2003)
[文献書誌] S.Okubo: "High Magnetic Field ESR Study of Field Induced Antiferromagnetic Ordering in CsFeBr_3 at Low Temperature"Physica B. 329-333. 1069-1070 (2003)
[文献書誌] O.Vyaselev: "Field-Induced Magnetic Ordering in TlCuCl_3 : Lattice Deformation and Features of First-Order Transition"Physica B. 329-333. 892-893 (2003)
[文献書誌] H.Tanaka: "Magnetic Ordering under High Pressure in Quantum Spin System TlCuCl_3"Physica B. 329-333. 697-698 (2003)
[文献書誌] K.-Y.Choi: "Spin Dynamics of Spin Dimer System TlCuCl_3 Probed by Raman Spectroscopy"Phys.Rev.B. 68. 174412-1-174412-6 (2003)
[文献書誌] H.Tanaka: "Electron Spin Resonance in Triangular Antiferromagnets"J.Phys.Soc.Jpn.. 72 Suppl.B. 84-98 (2003)
[文献書誌] H.Nojiri: "THz-ESR System by Using Single Shot and Repeating Pulsed Magnetic Fields"J.Phys.Soc.Jpn.. 72 Suppl.B. 109-116 (2003)
[文献書誌] Y.Inagaki: "Field Induced Magnetic Ordering in CsFeBr_3 Studied by High Field ESR"J.Phys.Soc.Jpn.. 72 Suppl.B. 127-134 (2003)
[文献書誌] T.Sakurai: "High Field ESR Measurements under Pressure"J.Phys.Soc.Jpn.. 72 Suppl.B. 156-161 (2003)
[文献書誌] A.Oosawa: "Neutron Diffraction Study of the Pressure-Induced Magnetic Ordering in the Spin Gap System TlCuCl_3"J.Phys.Soc.Jpn.. 72. 1026-1029 (2003)
[文献書誌] E.Ya.Sherman: "Sound Attenuation on the Bose-Einstein Condensation of Magnons in TlCuCl_3"Phys.Rev.Lett.. 91. 057201-1-057201-4 (2003)
[文献書誌] M.Oshikawa: "Insulator, Conductor, and Commensurability : A Topological Approach"Phys.Rev.Lett.. 90. 236401 (2003)
[文献書誌] Y.Maeda: "Numerical analysis of electron-spin resonance in the spin-(1/2)XY model"Phys.Rev.B. 67. 224424 (2003)
[文献書誌] Y.Saiga: "Coexistence of dx^2-y^2 wave superconductivity and antiferromagnetism induced by a staggered field"Phys.Rev.B. 68. 094511 (2003)
[文献書誌] M.Oshikawa: "Comment on "Confinement of Slave Particles in U(1) Gauge Theories of Strongly Interacting Electrons""Phys.Rev.Lett.. 91. 199701 (2003)
[文献書誌] C.Chamon: "Junctions of Three Quantum Wires and the Dissipative Hofstadter Model"Phys.Rev.Lett.. 91. 206403 (2003)
[文献書誌] N.V.Baranov: "Slow dynamics of the magnetization in the ordered state of molecule based magnets with one-dimensional chain structure"J.Phys.: Condens.Matter. 15. 8881-8897 (2003)
[文献書誌] T.Goto: "High field magnetization process of BIPNNBNO and PIMBNO at low temperature"Physica B. 329-333. 1160-1161 (2003)
[文献書誌] Y.Yoshida: "Field-induced magnetic ordering in an alternation Heisenberg chain F_5PNN"Physica B. 329-333. 979-980 (2003)
[文献書誌] K.Izumi: "Nuclear magnetic relaxation of ^<19>F in S=1/2 bond-alternationg organic compound F_5PNN"Physica B. 329-333. 1191-1192 (2003)
[文献書誌] T.Sakai: "Magnetization plateau in S=1 organic spin ladder BIP-TENO"Physica B. 329-333. 1203-1204 (2003)
[文献書誌] M.Doerr: "Pressure dependent magnetization of DyCu_2 single crystals"Physica B. 329-333. 633-634 (2003)
[文献書誌] M.Tamura: "Magnetic Properties and Structures of the α- and δ-Phases of p-NPNN"J.Phys.Soc.Jpn.. 72. 1735-1744 (2003)
[文献書誌] K.Mukai: "Genuine organic magnetic semiconductors : electrical and magnetic properties of the TCNQ and iodide salts of methylpyridinium-substituted verdazyl radicals"J.Mater.Chem.. 13. 1614-1621 (2003)
[文献書誌] Y.Hosokoshi: "Magnetic properties on an organic ferrimagnetic compound and related materials"Synth.Metals. 133. 527-530 (2003)
[文献書誌] T.Naito: "Physical properties of(ET)_3(MnCl_4)(TCE)and the related salts"Synth.Metals. 135. 613-614 (2003)
[文献書誌] T.Sakai: "Magnetization plateaux in S=1 spin ladder"Phys.Stat.Sol.. 236. 429-432 (2003)
[文献書誌] K.Nagayoshi: "Design of Novel Inorganic-Organic Hybrid Materials Based on Iron-Chloranilate Mononuclear Complexes : Characteristics of Hudrogen-Bond-Supported Layers toward the Intercalation of Guests"J.Am.Chem.Soc.. 125. 221-232 (2003)

2003 年度 実績報告書

磁場が誘起するマグノンのボース・アインシュタイン凝縮と局在

研究代表者

田中 秀数 東京工業大学, 極低温物性研究センター, 教授 (80188325)

研究成果

[文献書誌] A.Oosawa: "Neutron Scattering Study of Magnetic Ordering and Excitations in the Doped Spin Gap System Tl(Cu_<1-x>Mg_x)Cl_3"Phys.Rev.B. 67. 184424-1-184424-8 (2003)

[文献書誌] T.Ono: "Magnetization Plateau in the Frustrated Quantum Spin System Cs_2CuBr_4"Phys.Rev.B. 67. 104431-1-104431-7 (2003)

[文献書誌] M.Fujisawa: "Crystal Structure and Magnetic Properties of the Quasi-One-Dimensional Quantum Spin System Cu_2Cl_4・H_8C_4SO_2"J.Phys.Soc.Jpn.. 72. 694-697 (2003)

[文献書誌] S.Hosoya: "NMR Study on the Quantum Spin Ladder NH_4CuCl_3"Physica B. 329-333. 977-978 (2003)

[文献書誌] H.Nojiri: "Coexistence of Gap-less and Gapped Excitations in NH_4 CuCl_3"Physica B. 329-333. 701-702 (2003)

[文献書誌] Y.Shimaoka: "NMR Study of Magnetic Structures in NH_4CuCl_3"Physica B. 329-333. 894-895 (2003)

[文献書誌] S.Okubo: "High Magnetic Field ESR Study of Field Induced Antiferromagnetic Ordering in CsFeBr_3 at Low Temperature"Physica B. 329-333. 1069-1070 (2003)

[文献書誌] O.Vyaselev: "Field-Induced Magnetic Ordering in TlCuCl_3 : Lattice Deformation and Features of First-Order Transition"Physica B. 329-333. 892-893 (2003)

[文献書誌] H.Tanaka: "Magnetic Ordering under High Pressure in Quantum Spin System TlCuCl_3"Physica B. 329-333. 697-698 (2003)

[文献書誌] K.-Y.Choi: "Spin Dynamics of Spin Dimer System TlCuCl_3 Probed by Raman Spectroscopy"Phys.Rev.B. 68. 174412-1-174412-6 (2003)

[文献書誌] H.Tanaka: "Electron Spin Resonance in Triangular Antiferromagnets"J.Phys.Soc.Jpn.. 72 Suppl.B. 84-98 (2003)

[文献書誌] H.Nojiri: "THz-ESR System by Using Single Shot and Repeating Pulsed Magnetic Fields"J.Phys.Soc.Jpn.. 72 Suppl.B. 109-116 (2003)

[文献書誌] Y.Inagaki: "Field Induced Magnetic Ordering in CsFeBr_3 Studied by High Field ESR"J.Phys.Soc.Jpn.. 72 Suppl.B. 127-134 (2003)

[文献書誌] T.Sakurai: "High Field ESR Measurements under Pressure"J.Phys.Soc.Jpn.. 72 Suppl.B. 156-161 (2003)

[文献書誌] A.Oosawa: "Neutron Diffraction Study of the Pressure-Induced Magnetic Ordering in the Spin Gap System TlCuCl_3"J.Phys.Soc.Jpn.. 72. 1026-1029 (2003)

[文献書誌] E.Ya.Sherman: "Sound Attenuation on the Bose-Einstein Condensation of Magnons in TlCuCl_3"Phys.Rev.Lett.. 91. 057201-1-057201-4 (2003)

[文献書誌] M.Oshikawa: "Insulator, Conductor, and Commensurability : A Topological Approach"Phys.Rev.Lett.. 90. 236401 (2003)

[文献書誌] Y.Maeda: "Numerical analysis of electron-spin resonance in the spin-(1/2)XY model"Phys.Rev.B. 67. 224424 (2003)

[文献書誌] Y.Saiga: "Coexistence of dx^2-y^2 wave superconductivity and antiferromagnetism induced by a staggered field"Phys.Rev.B. 68. 094511 (2003)

[文献書誌] M.Oshikawa: "Comment on "Confinement of Slave Particles in U(1) Gauge Theories of Strongly Interacting Electrons""Phys.Rev.Lett.. 91. 199701 (2003)

[文献書誌] C.Chamon: "Junctions of Three Quantum Wires and the Dissipative Hofstadter Model"Phys.Rev.Lett.. 91. 206403 (2003)

[文献書誌] N.V.Baranov: "Slow dynamics of the magnetization in the ordered state of molecule based magnets with one-dimensional chain structure"J.Phys.: Condens.Matter. 15. 8881-8897 (2003)

[文献書誌] T.Goto: "High field magnetization process of BIPNNBNO and PIMBNO at low temperature"Physica B. 329-333. 1160-1161 (2003)

[文献書誌] Y.Yoshida: "Field-induced magnetic ordering in an alternation Heisenberg chain F_5PNN"Physica B. 329-333. 979-980 (2003)

[文献書誌] K.Izumi: "Nuclear magnetic relaxation of ^<19>F in S=1/2 bond-alternationg organic compound F_5PNN"Physica B. 329-333. 1191-1192 (2003)

[文献書誌] T.Sakai: "Magnetization plateau in S=1 organic spin ladder BIP-TENO"Physica B. 329-333. 1203-1204 (2003)

[文献書誌] M.Doerr: "Pressure dependent magnetization of DyCu_2 single crystals"Physica B. 329-333. 633-634 (2003)

[文献書誌] M.Tamura: "Magnetic Properties and Structures of the α- and δ-Phases of p-NPNN"J.Phys.Soc.Jpn.. 72. 1735-1744 (2003)

[文献書誌] K.Mukai: "Genuine organic magnetic semiconductors : electrical and magnetic properties of the TCNQ and iodide salts of methylpyridinium-substituted verdazyl radicals"J.Mater.Chem.. 13. 1614-1621 (2003)

[文献書誌] Y.Hosokoshi: "Magnetic properties on an organic ferrimagnetic compound and related materials"Synth.Metals. 133. 527-530 (2003)

[文献書誌] T.Naito: "Physical properties of(ET)_3(MnCl_4)(TCE)and the related salts"Synth.Metals. 135. 613-614 (2003)

[文献書誌] T.Sakai: "Magnetization plateaux in S=1 spin ladder"Phys.Stat.Sol.. 236. 429-432 (2003)

[文献書誌] K.Nagayoshi: "Design of Novel Inorganic-Organic Hybrid Materials Based on Iron-Chloranilate Mononuclear Complexes : Characteristics of Hudrogen-Bond-Supported Layers toward the Intercalation of Guests"J.Am.Chem.Soc.. 125. 221-232 (2003)

2003 年度実績報告書

田中秀数東京工業大学, 極低温物性研究センター, 教授 (80188325)