2001 Fiscal Year Annual Research Report

複合自由度をもつ電子系の創製と新機能開拓

Research Project

Project/Area Number	13CE2002
Research Category	Grant-in-Aid for COE Research
Research Institution	Hiroshima University
Principal Investigator	高畠敏郎広島大学, 大学院・先端物質科学研究科, 教授 (40171540)
Co-Investigator(Kenkyū-buntansha)	世良正文広島大学, 大学院・先端物質科学研究科, 教授 (40196978) 藤井博信広島大学, 総合科学部, 教授 (30034573) 山中昭司広島大学, 大学院・工学研究科, 教授 (90081314) 小口多美夫広島大学, 大学院・先端物質科学研究科, 教授 (90253054) 谷口雅樹広島大学, 大学院・理学研究科, 教授 (10126120)
Keywords	窒化物超伝導体 / 熱電変換物質 / 水素貯蔵物質 / コンダクタンスゆらぎ / ラマン散乱 / トンネル分光 / 放射光光電子分光 / バンド計算
Research Abstract	本年度は、すきまと電子系の複合自由度を活かした物質の創製と、超伝導、熱電変換、水素貯蔵などの新機能の開拓を推進する研究協力体制を確立し、計画していた設備備品を導入し、以下の成果をあげた。 1.新化合物創製グループ山中らは、層状窒化物β-HfNC1中のClの部分的除去によって、電子ドープ超伝導(Tc=24K)を出現させた。一連のβ-MNX(M=Zr, Hf, X=Cl, Br, I)の単結晶化に成功し、2種類の多形の存在を見出した。高圧合成によってC_<60>ポリマー単結晶を初めて合成しその構造を決定した。高畠らは、希土類のCe, Sm, Eu, Ybを含む多数の化合物を合成し、その中で、偽ギャップをもつCeRhAsと金属的なCeRhSnが液体窒素温度領域で従来のBi系材料よりも優れた熱電変換特性をもつことを見出した。研究協力者の伊賀らは、Yb_<1-x>La_xB_6(x<0.006)が150Kの高いキュリー温度をもつ強磁性体である事を発見した。 2.ナノ構造機能創製グループ藤井らはPd/Mg多層膜をナノ柱状粒構造にすることによって、水素を100℃以下でも5wt%以上吸放出させただけでなく、吸蔵による光透過機能を発見した。ナノ構造化させたグラファイトに水素を7.4重量%も吸蔵させる事に成功し、水素の大部分が刃状転位付近にトラップされている事を中性子回折法で確かめた。八木は強磁性Niの線幅35ナノメートルのリングと細線を作製し、極低温磁気抵抗において、よく再現する大局的構造を見出し、普遍的コンダクタンスゆらぎの可能性を指摘した。 3.固体物性測定グループ世良らは層状ホウ化物超伝導体MgB_2の熱輸送特性の測定から、2種類のキャリアの存在を指摘し、電子状態密度がフェルミ準位付近で大きく変化していると結論した。研究協力者の籐は、本年度購入した核磁気共鳴装置を立ち上げた。さらに、山中らが窒素の同位元素で合成したLi-HfNC1の超伝導転移温度が同位元素の質量によらないことから、その超伝導は通常の電子・格子相互作用以外の機構によると提案した。藤田と鈴木らは、高圧で安定化させたLSCO高温正方晶における電気伝導と次元の相関を指摘し、P波超伝導体Sr_2RuO_4及び電子ドープ超伝導体NCCOの超伝導状態の歪み応答を明らかにした。 4.分光測定グループ固体分光測定:宇田川らは低密度キャリア強磁性体CaB_6のラマン散乱分光によって、B_6八面体内の異方的電荷分布が正方晶的歪を生じさせることを見出し、これが強磁性発現と深く関わっていると指摘した。ナノ構造化グラファイト中の水素の結合状態はC-H_2とC-H_3であり、前者が大部分である事を赤外吸収によって確かめた。浴野らはトンネル分光によって、MgB_2の超伝導ギャップに多重構造を見出し、2バンドモデルを提案した。山中の合成した層状窒化物は強結合超伝導体であるとの結果を得た。放射光測定:谷口と生天目らは、HiSORのアンジュレータビームラインのエネルギー分解能向上に努め、120eVでは16meV、30eV以下では4.5meVという世界最高の分解能を実現した。4f電子状態を選択的に見ることができる前者の放射光を用いて近藤半導体CeRhAsのギャップを、後者を用いてYbB_6のフェルミ面近傍でのバンド分散を直接観測した。その解析を理論解析班の支援によって進めた。 5.理論解析・物質設計グループ層状超伝導体や希土類化合物などのエネルギーバンドを、小口らは相対論効果を取り入れた第一原理計算によって計算し、光電子分光及びシェブニコフドハース効果の実験との比較を進めた。研究協力者の森は、金の極細線における電子の磁場下での非局在化を明らかにした。城らはペロフスカイト型Ti酸化物についてスピン軌道相互作用、軌道縮重度、電子間多重極相互作用を取り入れた理論を作り、YTiO_3のC型軌道秩序がエネルギー的に安定である事、LaTiO_3の磁気モーメントが主に軌道磁気モーメントから生じている事を導出した。永井らは、超伝導近接接合系おける接合面の粗さと不純物の効果を考慮した理論をs波とd波の超伝導体について展開した。

Research Products

(44 results)

All Other

All Publications (44 results)

[Publications] H.Tou: "Unconventional Superconductivity in Electron-Doped Layered Hafnium Nitride Li_<0.48>(THF)_yHfNCl"Phys. Rev. Lett.. 86. 5775-5778 (2001)
[Publications] T.Yokoya: "Electronic structure and superconducting gap of silicon clatlirate Bas_8Si_<46> studied with ultrahigh-resolution photoemission spectroscopy"Phys. Rev. B. 64. 172504-1-172504-4 (2001)
[Publications] M.Yasukawa: "Synthesis of Li_xC_<60> (x=1-28) fullerides under high-pressure and high-temperature conditions and their electrical properties"Chem. Phys. Lett. 341. 467-475 (2001)
[Publications] X.Chen: "High-pressure synthesis and crystal structures of β-MNX(M=Zr, Hf: X=Br, I)"J. Solid State Chem.. (in press). (2002)
[Publications] L.Zhu: "Novel synthesis of TiN fine powders by nitridation with ammonium chloride"Mater. Res. Bull.. 1920(in press). 1-9 (2002)
[Publications] F.Iga: "Thermoelectric properties of the Kondo semiconductor: Yb_<1-x>Lu_xB_<12>"J. Magn. Magn. Mater.. 226-230. 85-86 (2001)
[Publications] M.H.Jung: "Thermoelectric and transport properties of CeBiPt and LaBiPt"J. Appi. Phys.. 89(11). 7631-7633 (2001)
[Publications] K.Umeo: "Pressure-induced magnetic instability in Ce_2Rh_3Ge_5"Phys. Rev. B. 64. 144412-144419 (2001)
[Publications] T.Takabatake: "Kondo semiconductors as a novel thermoelectric-cooling material"Proc. 20^<th> Int. Conf on. Thermoelecytics. 266-269 (2002)
[Publications] J.Kitagawa: "Thermoelectric Properties of Valence-Fluctuating Eu Compound with a Clatlirate-like Structure, Eu_3Pd_<20>Ge_6"J. Phys. Soc. Jpn. 71(in press). (2002)
[Publications] S.Orimo: "Materials science of Mg-Ni based new hydrides"Appl. Phys. A. 72. 167-186 (2001)
[Publications] S.Orimo: "Hydrogen desorption property of the mechanically prepared nanostructured graphite"Appl. Phys.. 90. 1545-1549 (2001)
[Publications] T.Fukunaga: "Location of deuterium atoms absorbed in nanocrystalline graphite prepared by mechanical alloying"J. Alloys and Compounds. 327. 224-229 (2001)
[Publications] H.Fujii: "Effect of mechanical grinding under Ar and H_2 atomospheres on structural and hydriding properties in LaNi_5"J. Alloys and Compounds. 330-332. 747-751 (2002)
[Publications] P.Wang: "Hydrogen in mechanically prepared nanostructwred h-BN: a critical comparison with that in nanostructured graphite"Appl. Phys. Lett.. 80. 318-320 (2002)
[Publications] T.Yamaguchi: "Phase diagram for two-dimensional arrays of small Josephson junctions with shunt resisters"Physica C. 352. 181-185 (2001)
[Publications] T.Muranaka: "Thermal Transport properties of MgB_2"Phys.Rev.B. 64. 0250502-020507(R) (2001)
[Publications] S.Tsuji: "Analysis of ^<11>B-NMR in phase II of CeB_6"J. Phys. Soc. Jpn.. 70. 41-44 (2001)
[Publications] M.Sera: "Anomalous Thmperature Dependence of the Magnetic Field Induced Antiferro-Magnetic Moment in the Antiferro-Quadrupolar Ordered State of CeB_6"Phys. Rev. Lett.. 86. 1578-1581 (2001)
[Publications] M.Sera: "Ce site substitution effects on the multipolar interactions in CeB_6"J. Phys. Soc. Jpn.. 71, Suppl(in press). (2002)
[Publications] H.Tou: "Evidenc e for Quasi-Two-Dimensional Superconductivity in Electron-Doped Li_<0.48>(THF)_yHfNCl"Phys. Rev. B.. 63. 020508-020611 (2001)
[Publications] N.Okuda: "Elastic moduli of unconventional Superconductor Sr_2RuO_4"Physica B. 312-313(in press). (2001)
[Publications] N.Okuda: "Unconventional strain dependence of superconductivity in spin-triplet superconductor Sr_2RuO_4"J. Phys. Soc. Jpn.. 71(in press). (2002)
[Publications] T.Suzuki: "Elastic anomaly of UCu_2Sn in the magnetic fields"J. Magn. Magn. Mater.. 226. 983-984 (2001)
[Publications] T.Fujita: "Superconductor-insulator transition in under-doped cuprates"Physica C. 364-365. 274-277 (2001)
[Publications] M.Udagawa: "Raman scattering investigation of high temperature ferromagnetic crystals"J. Phys. Soc. Jpn.. 71, Suppl.. 1-3 (2002)
[Publications] S.Sakita: "Anisotropic properties of the excitation spectrum of Sr_2RuO_4 crystals (T_c=1.4K) in the normal state investigated by Raman scattering"Phys.Rev.B. 63. 134520-1-134520-5 (2001)
[Publications] Z.Q.Mao: "Sign reversal of the oxygen isotope effect on T_c in Sr_2RuO_4"Phys.Rev.B. 63. 144514-1-144514-5 (2001)
[Publications] T.Ekino: "Tunneling spectroscopy of the normal-state gap in (Bi, Pb)_2Sr_2Ca_2Cu_3O_<10+δ>"Phys.Rev.B. 64. 092510-1-092510-4 (2001)
[Publications] T.Ekino: "Probing the normal-state gap in high-T_c superconductors by break-junction tunneling"J. Phys. Chem. of Solids. 62. 149-152 (2001)
[Publications] T.Ekino: "Tunneling spectroscopy of the energy gap in semiconducting La_<1.98>Sr_<0.02>CuO_4"Physica C. 357. 158-161 (2001)
[Publications] T.Ekino: "Energy gap in the Kondo semiconductor CeRhAs"Physica B. (in press). (2002)
[Publications] T.Susaki: "Photoemission study of substitution effects on the conduction-Band States in the Kondo insulator YbB_<12>"J. Phys. Soc. Jpn.. 70. 756-761 (2001)
[Publications] K.Shimada: "Temperature-dependent metal-insulator transition in d-and f-electron systems studied by high-resolution photoemission spectroscopy"J. Electron Spectrosc. Relat. Phenom.. 114-116. 711-716 (2001)
[Publications] T.Oguchi: "Electronic band structure and structural stability of LaBiPt"Phys.Rev.B. 63. 125115-1-125115-5 (2001)
[Publications] J.Nakamura: "Electromc Structure of B-2p States in AlB_2 Single Crystal Direct Observation of pσ and pπ Density of States"J. Phys. Soc. Jpn.. 71(in press). (2002)
[Publications] T.Oguchi: "Cohesion in AlB_2-Type Diborides: A First-Principles Study"J. Phys. Soc. Jpn.. (in press). (2002)
[Publications] H.Mori: "Delocalization of one-climensional electrons with quenched disorder in a weak magnetic field"Phys. Rev. B. (in press). (2002)
[Publications] T.Jo: "Hartree-Fock study oforbital magnetic moments in 3d and 5f magnets and X-ray magnetic circular dichroism"J. Synchrotron Rad.. 8. 115-119 (2001)
[Publications] T.Jo: "Theory of spectroscopies in nickel, cerium compounds and other systems"J. Electron Spectroec. Relat. Phenom.. 117-118. 397-411 (2002)
[Publications] T.Jo: "Orbital Ordering and Jahn-Teller Distortion in YTiO_3"J. Phys. Soc. Jpn.. 70. 3180-3181 (2001)
[Publications] A.Tanaka: "Electronic Structure and phase Transition in V_2O_3: Importance of 3d Spin-Orbit Interaction and Lattice Distortion"J. Phys. Soc. Jpn.. 71(in press). (2002)
[Publications] T.Ichikawa: "Collision Drag Effect on Propagation of Sound in Liquid ^3He in Aerogl"J. Phys. Soc. Jpn.. 70. 3483-3486 (2001)
[Publications] K.Yamada: "Rough Surface Effect on Meissner Diamagnetism in Normal-Layer of N-S Proximity-Contact System"J. Phys. Soc. Jpn.. 71. 293-299 (2002)

2001 Fiscal Year Annual Research Report

複合自由度をもつ電子系の創製と新機能開拓

Principal Investigator

高畠 敏郎 広島大学, 大学院・先端物質科学研究科, 教授 (40171540)

Research Products

[Publications] H.Tou: "Unconventional Superconductivity in Electron-Doped Layered Hafnium Nitride Li_<0.48>(THF)_yHfNCl"Phys. Rev. Lett.. 86. 5775-5778 (2001)

[Publications] T.Yokoya: "Electronic structure and superconducting gap of silicon clatlirate Bas_8Si_<46> studied with ultrahigh-resolution photoemission spectroscopy"Phys. Rev. B. 64. 172504-1-172504-4 (2001)

[Publications] M.Yasukawa: "Synthesis of Li_xC_<60> (x=1-28) fullerides under high-pressure and high-temperature conditions and their electrical properties"Chem. Phys. Lett. 341. 467-475 (2001)

[Publications] X.Chen: "High-pressure synthesis and crystal structures of β-MNX(M=Zr, Hf: X=Br, I)"J. Solid State Chem.. (in press). (2002)

[Publications] L.Zhu: "Novel synthesis of TiN fine powders by nitridation with ammonium chloride"Mater. Res. Bull.. 1920(in press). 1-9 (2002)

[Publications] F.Iga: "Thermoelectric properties of the Kondo semiconductor: Yb_<1-x>Lu_xB_<12>"J. Magn. Magn. Mater.. 226-230. 85-86 (2001)

[Publications] M.H.Jung: "Thermoelectric and transport properties of CeBiPt and LaBiPt"J. Appi. Phys.. 89(11). 7631-7633 (2001)

[Publications] K.Umeo: "Pressure-induced magnetic instability in Ce_2Rh_3Ge_5"Phys. Rev. B. 64. 144412-144419 (2001)

[Publications] T.Takabatake: "Kondo semiconductors as a novel thermoelectric-cooling material"Proc. 20^<th> Int. Conf on. Thermoelecytics. 266-269 (2002)

[Publications] J.Kitagawa: "Thermoelectric Properties of Valence-Fluctuating Eu Compound with a Clatlirate-like Structure, Eu_3Pd_<20>Ge_6"J. Phys. Soc. Jpn. 71(in press). (2002)

[Publications] S.Orimo: "Materials science of Mg-Ni based new hydrides"Appl. Phys. A. 72. 167-186 (2001)

[Publications] S.Orimo: "Hydrogen desorption property of the mechanically prepared nanostructured graphite"Appl. Phys.. 90. 1545-1549 (2001)

[Publications] T.Fukunaga: "Location of deuterium atoms absorbed in nanocrystalline graphite prepared by mechanical alloying"J. Alloys and Compounds. 327. 224-229 (2001)

[Publications] H.Fujii: "Effect of mechanical grinding under Ar and H_2 atomospheres on structural and hydriding properties in LaNi_5"J. Alloys and Compounds. 330-332. 747-751 (2002)

[Publications] P.Wang: "Hydrogen in mechanically prepared nanostructwred h-BN: a critical comparison with that in nanostructured graphite"Appl. Phys. Lett.. 80. 318-320 (2002)

[Publications] T.Yamaguchi: "Phase diagram for two-dimensional arrays of small Josephson junctions with shunt resisters"Physica C. 352. 181-185 (2001)

[Publications] T.Muranaka: "Thermal Transport properties of MgB_2"Phys.Rev.B. 64. 0250502-020507(R) (2001)

[Publications] S.Tsuji: "Analysis of ^<11>B-NMR in phase II of CeB_6"J. Phys. Soc. Jpn.. 70. 41-44 (2001)

[Publications] M.Sera: "Anomalous Thmperature Dependence of the Magnetic Field Induced Antiferro-Magnetic Moment in the Antiferro-Quadrupolar Ordered State of CeB_6"Phys. Rev. Lett.. 86. 1578-1581 (2001)

[Publications] M.Sera: "Ce site substitution effects on the multipolar interactions in CeB_6"J. Phys. Soc. Jpn.. 71, Suppl(in press). (2002)

[Publications] H.Tou: "Evidenc e for Quasi-Two-Dimensional Superconductivity in Electron-Doped Li_<0.48>(THF)_yHfNCl"Phys. Rev. B.. 63. 020508-020611 (2001)

[Publications] N.Okuda: "Elastic moduli of unconventional Superconductor Sr_2RuO_4"Physica B. 312-313(in press). (2001)

[Publications] N.Okuda: "Unconventional strain dependence of superconductivity in spin-triplet superconductor Sr_2RuO_4"J. Phys. Soc. Jpn.. 71(in press). (2002)

[Publications] T.Suzuki: "Elastic anomaly of UCu_2Sn in the magnetic fields"J. Magn. Magn. Mater.. 226. 983-984 (2001)

[Publications] T.Fujita: "Superconductor-insulator transition in under-doped cuprates"Physica C. 364-365. 274-277 (2001)

[Publications] M.Udagawa: "Raman scattering investigation of high temperature ferromagnetic crystals"J. Phys. Soc. Jpn.. 71, Suppl.. 1-3 (2002)

[Publications] S.Sakita: "Anisotropic properties of the excitation spectrum of Sr_2RuO_4 crystals (T_c=1.4K) in the normal state investigated by Raman scattering"Phys.Rev.B. 63. 134520-1-134520-5 (2001)

[Publications] Z.Q.Mao: "Sign reversal of the oxygen isotope effect on T_c in Sr_2RuO_4"Phys.Rev.B. 63. 144514-1-144514-5 (2001)

[Publications] T.Ekino: "Tunneling spectroscopy of the normal-state gap in (Bi, Pb)_2Sr_2Ca_2Cu_3O_<10+δ>"Phys.Rev.B. 64. 092510-1-092510-4 (2001)

[Publications] T.Ekino: "Probing the normal-state gap in high-T_c superconductors by break-junction tunneling"J. Phys. Chem. of Solids. 62. 149-152 (2001)

[Publications] T.Ekino: "Tunneling spectroscopy of the energy gap in semiconducting La_<1.98>Sr_<0.02>CuO_4"Physica C. 357. 158-161 (2001)

[Publications] T.Ekino: "Energy gap in the Kondo semiconductor CeRhAs"Physica B. (in press). (2002)

[Publications] T.Susaki: "Photoemission study of substitution effects on the conduction-Band States in the Kondo insulator YbB_<12>"J. Phys. Soc. Jpn.. 70. 756-761 (2001)

[Publications] K.Shimada: "Temperature-dependent metal-insulator transition in d-and f-electron systems studied by high-resolution photoemission spectroscopy"J. Electron Spectrosc. Relat. Phenom.. 114-116. 711-716 (2001)

[Publications] T.Oguchi: "Electronic band structure and structural stability of LaBiPt"Phys.Rev.B. 63. 125115-1-125115-5 (2001)

[Publications] J.Nakamura: "Electromc Structure of B-2p States in AlB_2 Single Crystal Direct Observation of pσ and pπ Density of States"J. Phys. Soc. Jpn.. 71(in press). (2002)

[Publications] T.Oguchi: "Cohesion in AlB_2-Type Diborides: A First-Principles Study"J. Phys. Soc. Jpn.. (in press). (2002)

[Publications] H.Mori: "Delocalization of one-climensional electrons with quenched disorder in a weak magnetic field"Phys. Rev. B. (in press). (2002)

[Publications] T.Jo: "Hartree-Fock study oforbital magnetic moments in 3d and 5f magnets and X-ray magnetic circular dichroism"J. Synchrotron Rad.. 8. 115-119 (2001)

[Publications] T.Jo: "Theory of spectroscopies in nickel, cerium compounds and other systems"J. Electron Spectroec. Relat. Phenom.. 117-118. 397-411 (2002)

[Publications] T.Jo: "Orbital Ordering and Jahn-Teller Distortion in YTiO_3"J. Phys. Soc. Jpn.. 70. 3180-3181 (2001)

[Publications] A.Tanaka: "Electronic Structure and phase Transition in V_2O_3: Importance of 3d Spin-Orbit Interaction and Lattice Distortion"J. Phys. Soc. Jpn.. 71(in press). (2002)

[Publications] T.Ichikawa: "Collision Drag Effect on Propagation of Sound in Liquid ^3He in Aerogl"J. Phys. Soc. Jpn.. 70. 3483-3486 (2001)

[Publications] K.Yamada: "Rough Surface Effect on Meissner Diamagnetism in Normal-Layer of N-S Proximity-Contact System"J. Phys. Soc. Jpn.. 71. 293-299 (2002)

高畠敏郎広島大学, 大学院・先端物質科学研究科, 教授 (40171540)