2000 Fiscal Year Annual Research Report

ハルデン系物質Ln2BaNiO5(Ln:希土類元素)のドーピング効果と磁気励起

Research Project

Project/Area Number	12440105
Research Institution	Aoyama Gakuin University
Principal Investigator	秋光純青山学院大学, 理工学部, 教授 (80013522)
Co-Investigator(Kenkyū-buntansha)	銭谷勇磁青山学院大学, 理工学部, 助手 (50327285) 菊地淳東京理科大学, 理工学部, 助手 (90297614) 元屋清一郎東京理科大学, 理工学部, 教授 (60114683)
Keywords	ハルデン系 / 一重項状態 / 一次元系
Research Abstract	本研究では、Haldane系R_2BaNiO_5(R=希土類)における置換効果として、1)R=(Y_<1-x>Nd_x)とした場合の三次元秩序と一次元Haldane状態とが混在する系における磁気的な希釈効果、2)R=(Nd_<1-x>Ca_x)とした一次元Haldane鎖にホールを導入した系におけるギャップ内状態、という二つのテーマを掲げた。これまでに得られた成果を以下にまとめる。 1)R=(Y_<1-x>Nd_x):Nd_2BaNiO_5からYを固溶させてゆくことにより、人工的にNi-Haldane鎖に与える有効的な交代磁場を変化させる。我々はまずこの固溶系一連の試料合成を行い、帯磁率測定から転移点(T_N)の詳細な測定を行った。その結果、Ndの高濃度領域においては、Yのドープに伴ってT_Nは直線的に減少してゆく。これはNi-Nd間に働く超交換相互作用Jが薄められた結果全体としてJが小さくなっていると考えられ、平均場の描像で理解できる。中性子散乱実験よりx=1の場合、J=0.2meV程度の見積もりがなされており、一方Nd-Nd間の相互作用は非常に弱く無視してよいと考えることができる。この場合、三次元秩序を担っているのはNi-Nd間の交換相互作用であり、NdがYに置換されるとその経路が分断され"percolative"な振る舞いが生じると考えている。ただし、Ni一次元鎖自身もHaldane状態におけるスピン相関長を持っており、量子的なスピン相関と三次元的なパーコレーションとの協調現象である。 2)R=(Nd_<1-x>Ca_x):x=0.1の大型単結晶の育成に成功し、中性子弾性、非弾性散乱実験を行った。まず、これまで報告があったY_2BaNiO_5で観測されたギャップ内状態がNdの場合でも観測され、そのエネルギーは約4meVであった。このことは「Haldane状態」という現象に関してはランタノイドイオンは直接関係していない事を示している。また、三次元反強磁性の磁気Bragg点において磁気ピークが観測され、その温度変化は非常に特異である。

Research Products
(26 results)

All Other

All Publications (26 results)

[Publications] H.Ichikawa et.al.: "Direct Observation of Orbital Ordering in YTiO_3"Physica.B. 281-282. 482-484 (2000)
[Publications] S.Ohsugi et.al.: "Cu NMR and NQR studies on the magnetic order in Sr_<2.5>Ca_<11.5>Cu_<2441>"Physica.B. 284-288. (2000)
[Publications] Y.Gotoh et.al.: "Role of structural modulation in the composite crystal (Sr_2Cu_2O_3)_<0.70>CuO_2,"Sr_<14>Cu_<24>O_<41>" with two-legged spin ladder"Physica C. 341-348. 469-470 (2000)
[Publications] T.Nakanishi et.al.: "Upper Critical Field of Spin-Ladder Sr_2Ca_<12>Cu_<24>O_<41>"Physica.B. 281-282. 957-958 (2000)
[Publications] D.Braithwaite et.al.: "Upper Critical Field of the Spin Ladder System Sr_<2.5>Ca_<11.5>O_<41>"Solid State Commun.. 114. 533-536 (2000)
[Publications] M.Hiroi et.al.: "Study on CuGe_<0.9885>Si_<0.0115>O_3 in High Magnetic Fields by Specific Heat Measurements"Physica B. 281and282. 669-670 (2000)
[Publications] A.Zheludev et.al.: "Role of Single Ion Excitations in the Mixed-Spin Quasi-One-Dimensional Quantum Antiferromagnet Nd_2BaNiO_5"Phys.Rev.B. Vol.61. 11601-11612 (2000)
[Publications] T.Yokoo et.al.: "Magnetic Excitations in the Haldane System R_2BaNiO_5"J.Phys.Soc.Jpn.. 69Suppl.B. 95-101 (2000)
[Publications] 永田貴志 et.al.: "梯子格子系超伝導体;(Sr, Ca)_<14>Cu_<24>O_<41>の物性"物性研究. Vol.74 No.4. (2000)
[Publications] J.Kikuchi et.al.: "NMR and Newtron Scattering Studies of Quasi One-Dimensional Magnet CuV_2O_6"J.Phys.Soc.Jpn... Vol.69 No.8. 2660-2668 (2000)
[Publications] J.Akimitsu et.al.: "The magnetic ordering in the spin ladder compound Sr_<2.5>Ca_<11.5>Cu_<24>O_<41>"Physica.B.. 289-290. 157-160 (2000)
[Publications] K.Ohishi et.al.: "Anomalous field dependence of the vortex-core radius and magnetic penetration depth in YNi_2B_2C probed by μSR."Physica.B.. 289-290. 377-380 (2000)
[Publications] K.Ishii et.al.: "Appearance of magnetic long-range order in the spin ladder compound La_<1-x>Sr_xCuO_<2.5>"Physica.B.. 289-290. 165-167 (2000)
[Publications] K.Ohishi et.al.: "Spatially Modulated Antiferromagnetism in Sr_<2.5>Ca_<11.5>Cu_<24>O_<41> Probed by Muon Spin Relaxation"J.Phys.Soc.Jpn.. Vol.69 No.8. 2427-2430 (2000)
[Publications] 秋光純: "梯子型超伝導体発見と物性の追究,酸素が作る奇妙な物質"金属酸化物が拓く新しい科学. (2000)
[Publications] S.Ohsugi et.al.: "Cu NMR and NQR studies on the magnetic order in Sr_<2.5>Ca_<11.5>Cu_<24>O_<41>"Physica, B. 284-288. 1591-1592 (2000)
[Publications] A.Zheludev et.al.: "Role of singleion excitations in the mixed-spin quasi-one-dimensional quantum antiferromagnet Nd_2BaNiO_5"Phys.Rev.B. Vol61 No.17. 11601-11612 (2000)
[Publications] R.Kadono: "Anomalous local magnetic shielding effect at muon site in Sr_<2.5>Ca_<11.5>Cu_<24>O_<41> and Ce_<0.99>Cu_<2.02>Si_2"physica B. 289-290. 322-325 (2000)
[Publications] K.Kakuta et.al.: "Antiferromagnet (Ln, Ca) CuO_<2.5> near the quantum critical point (Ln=Pr, Nd)"Physica B. 289-290. 168-171 (2000)
[Publications] N.Ogita et.al.: "Raman scattering of Sr_<14-x>Ca_xCu_<24>O_<41>"Physica, B. 281&282. 955-956 (2000)
[Publications] M.Nishi et.al.: "Lattice dynamics of CuGeO_3 by inelastic neutron scattering"J.Phy.Chem.Sol.. 62. 355-356 (2000)
[Publications] J.Akimitsu: "Antiferromagnetism and Spin Gap State in the two-leg Ladder System"J.Phys.Chem.Solid. 65. 135-140 (2000)
[Publications] R.Kadono et.al.: "Spin Dynamics of 4f Electrons in CeB_6 Studied by Muon Spin Relaxation"J.Phys.Soc.Jpn.. Vol.69 No.10. 3189-3192 (2000)
[Publications] J.Kikuchi et.al.: "NMR and Neutron-Scattering Studies of Quasi One-Dimensional Magnet CuV_2O_6"J.Phys.Soc.Jpn.. 69. 2660-2668 (2000)
[Publications] J.Kikuchi. et.al.: "31P NMR Evidence for Two Gapped Spin Chains in (VO)_2P_2O_7"J.Phys.Soc.Jpn.. 69Suppl.B.. 102-107 (2000)
[Publications] J.Kikuchi et.al.: "NMR Study of the Spin-Gap Behavior in (VO)_2P_2O_7 and VOHPO_<40.5>H_2O"Physica B. 284-288. 1481-1482 (2000)

2000 Fiscal Year Annual Research Report

ハルデン系物質Ln2BaNiO5(Ln:希土類元素)のドーピング効果と磁気励起

Principal Investigator

秋光 純 青山学院大学, 理工学部, 教授 (80013522)

Research Products

[Publications] H.Ichikawa et.al.: "Direct Observation of Orbital Ordering in YTiO_3"Physica.B. 281-282. 482-484 (2000)

[Publications] S.Ohsugi et.al.: "Cu NMR and NQR studies on the magnetic order in Sr_<2.5>Ca_<11.5>Cu_<2441>"Physica.B. 284-288. (2000)

[Publications] Y.Gotoh et.al.: "Role of structural modulation in the composite crystal (Sr_2Cu_2O_3)_<0.70>CuO_2,"Sr_<14>Cu_<24>O_<41>" with two-legged spin ladder"Physica C. 341-348. 469-470 (2000)

[Publications] T.Nakanishi et.al.: "Upper Critical Field of Spin-Ladder Sr_2Ca_<12>Cu_<24>O_<41>"Physica.B. 281-282. 957-958 (2000)

[Publications] D.Braithwaite et.al.: "Upper Critical Field of the Spin Ladder System Sr_<2.5>Ca_<11.5>O_<41>"Solid State Commun.. 114. 533-536 (2000)

[Publications] M.Hiroi et.al.: "Study on CuGe_<0.9885>Si_<0.0115>O_3 in High Magnetic Fields by Specific Heat Measurements"Physica B. 281and282. 669-670 (2000)

[Publications] A.Zheludev et.al.: "Role of Single Ion Excitations in the Mixed-Spin Quasi-One-Dimensional Quantum Antiferromagnet Nd_2BaNiO_5"Phys.Rev.B. Vol.61. 11601-11612 (2000)

[Publications] T.Yokoo et.al.: "Magnetic Excitations in the Haldane System R_2BaNiO_5"J.Phys.Soc.Jpn.. 69Suppl.B. 95-101 (2000)

[Publications] 永田貴志 et.al.: "梯子格子系超伝導体;(Sr, Ca)_<14>Cu_<24>O_<41>の物性"物性研究. Vol.74 No.4. (2000)

[Publications] J.Kikuchi et.al.: "NMR and Newtron Scattering Studies of Quasi One-Dimensional Magnet CuV_2O_6"J.Phys.Soc.Jpn... Vol.69 No.8. 2660-2668 (2000)

[Publications] J.Akimitsu et.al.: "The magnetic ordering in the spin ladder compound Sr_<2.5>Ca_<11.5>Cu_<24>O_<41>"Physica.B.. 289-290. 157-160 (2000)

[Publications] K.Ohishi et.al.: "Anomalous field dependence of the vortex-core radius and magnetic penetration depth in YNi_2B_2C probed by μSR."Physica.B.. 289-290. 377-380 (2000)

[Publications] K.Ishii et.al.: "Appearance of magnetic long-range order in the spin ladder compound La_<1-x>Sr_xCuO_<2.5>"Physica.B.. 289-290. 165-167 (2000)

[Publications] K.Ohishi et.al.: "Spatially Modulated Antiferromagnetism in Sr_<2.5>Ca_<11.5>Cu_<24>O_<41> Probed by Muon Spin Relaxation"J.Phys.Soc.Jpn.. Vol.69 No.8. 2427-2430 (2000)

[Publications] 秋光純: "梯子型超伝導体発見と物性の追究,酸素が作る奇妙な物質"金属酸化物が拓く新しい科学. (2000)

[Publications] S.Ohsugi et.al.: "Cu NMR and NQR studies on the magnetic order in Sr_<2.5>Ca_<11.5>Cu_<24>O_<41>"Physica, B. 284-288. 1591-1592 (2000)

[Publications] A.Zheludev et.al.: "Role of singleion excitations in the mixed-spin quasi-one-dimensional quantum antiferromagnet Nd_2BaNiO_5"Phys.Rev.B. Vol61 No.17. 11601-11612 (2000)

[Publications] R.Kadono: "Anomalous local magnetic shielding effect at muon site in Sr_<2.5>Ca_<11.5>Cu_<24>O_<41> and Ce_<0.99>Cu_<2.02>Si_2"physica B. 289-290. 322-325 (2000)

[Publications] K.Kakuta et.al.: "Antiferromagnet (Ln, Ca) CuO_<2.5> near the quantum critical point (Ln=Pr, Nd)"Physica B. 289-290. 168-171 (2000)

[Publications] N.Ogita et.al.: "Raman scattering of Sr_<14-x>Ca_xCu_<24>O_<41>"Physica, B. 281&282. 955-956 (2000)

[Publications] M.Nishi et.al.: "Lattice dynamics of CuGeO_3 by inelastic neutron scattering"J.Phy.Chem.Sol.. 62. 355-356 (2000)

[Publications] J.Akimitsu: "Antiferromagnetism and Spin Gap State in the two-leg Ladder System"J.Phys.Chem.Solid. 65. 135-140 (2000)

[Publications] R.Kadono et.al.: "Spin Dynamics of 4f Electrons in CeB_6 Studied by Muon Spin Relaxation"J.Phys.Soc.Jpn.. Vol.69 No.10. 3189-3192 (2000)

[Publications] J.Kikuchi et.al.: "NMR and Neutron-Scattering Studies of Quasi One-Dimensional Magnet CuV_2O_6"J.Phys.Soc.Jpn.. 69. 2660-2668 (2000)

[Publications] J.Kikuchi. et.al.: "31P NMR Evidence for Two Gapped Spin Chains in (VO)_2P_2O_7"J.Phys.Soc.Jpn.. 69Suppl.B.. 102-107 (2000)

[Publications] J.Kikuchi et.al.: "NMR Study of the Spin-Gap Behavior in (VO)_2P_2O_7 and VOHPO_<40.5>H_2O"Physica B. 284-288. 1481-1482 (2000)

秋光純青山学院大学, 理工学部, 教授 (80013522)