STUDY OF QUANTUM SPIN EFFECTS IN BOND ALTERNATING CHAIN AND SPIN LADDER SYSTEMS USING MOLECULE-BASED MAGNETIC COMPLEXES.

使用基于分子的磁复合体研究键交替链和自旋梯系统中的量子自旋效应。

• 批准号: 07640468
• 负责人: AJIRO Yoshitami
• 金额: $ 1.34万
• 依托单位: KYUSHU UNIVERSITY (1996)University of Fukui (1995)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640468/
• 关键词: Low Dimensional Magnet; Quantum Spin; Haldane System; Spin-Peierls System; Bond Alternating Chain; Spin Ladder; Spin Gap; Model Compound; 交互型反強磁性; 梯子型反強磁性

The purpose of the present research is to elucidate the quantum spin effects in low dimensional magnets, especially in bond alternating chain and spin ladder systems using molecule-based magnetic complexes. We performed various experiments including nuclear magnetic resonance (NMR), electron spin resonance (ECR), neutron scattering, muon spin relaxation (uSR), high field magnetization as well as susceptibility and specific measurements. We obtained the following results.1.Study of quantum effects of composite spin systems composed of S=1/2 subelements.(1) We studied new quantum spin effects in one-dimensional S=1/2 trimer systems, 3CuCl_2・dioxane and A_3Cu_3(PO_4)_4, in which ferromagnetic or antiferromagnetic trimers composed of three S=1/2 spins are respectively, weakly coupled antiferromagnetically in one dimension. We found peculiar magnetic properties characteristic of composite spin systems with nonuniform spatial structure.(2) We performed the susceptibility, high field magnetiz … More ation and NMR measurements on a S=1/2 alternating linear chain system CuCl_2・2picolin, uniform linear chain systemCuBr_2・2picolin and their mixed compounds CuCl_<281-x)>Br_<2x>・2picolin (0<x<1). We founda systematic change in singlet-ground-state properties as a function of composition as a result of a formation or destruction of the quantum spin gap due to the effects of bond alternation and randomness.2.Study of singlet-ground-state in antiferromagnetic quantum spin chains.(1) We performed a systematic study on the impurity effects on the intimately related quantum states in the Haldane and spin-Peierls systems, S=1 NiC_2O_4・2DMIz and S=1/2 CuGeO_3. We found that the SP state is very unstable and the broken SP state results in the appearance of the antiferromagnetic staggered moments, while the Haldane state is stable against nonmagnetic impurity doping up to 20%.(2) We performed the ESR measurements on the Zn-doped NENP,S=1 Haldane system with nonmagnetic impurities. A new interpretation was proposed that observed signals are due to the S=1/2 broken valence bond which is subjected to the field-induced staggered internal fields produced by the underlying antiferromagnetic lattice.(3) We studied the S=1 quasi-one dimensional Heisenbergantiferromagnet CsNiCl_3 which undergoes 3D ordering at T_N=4.8K,in order to revel the effect of the interchain coupling on the Haldane state. We found that the Haldane state really exists in the 1D phase above T_N. We confirmed the S=1/2 edge states characteristic of the Haldane state and revealed a crossover from the quantum to classical regimes as a function of both temperature and magnetic field. Less

本研究的目的是阐明低维磁体中的量子自旋效应，尤其是在键合链和使用基于分子的磁复合物的自旋梯子系统中。我们进行了各种实验，包括核磁共振（NMR），电子自旋共振（ECR），中子散射，MUON自旋弛豫（USR），高场磁化以及易感性和特定测量。我们获得了以下结果。1。由s = 1/2子元素组成的复合自旋系统的量子效应。（1）我们研究了一维S = 1/2的三分线剂系统中的新量子自旋效应，3cucl_2 dioxane和a_3cu_3（po_4）_4（po_4）_4（po_4）_4，其中fermagnetic contiferys contififorys contififorys contififorys contiforys Antercent and satterys and sytery and satter。旋转分别是在一个维度上弱耦合的抗磁磁性的。我们发现了具有不均匀空间结构的复合自旋系统的特征。（2）我们在s = 1/2上进行了易感性，高场磁铁…更多的ATION和NMR测量值替代线性链系统Cucl_2 cucl_2 ppicolin，均匀的线性链链SystemCubr_2ppicubr_2ppicubr and他们cucl_ <281-x）> br_ <2x> ・2picolin（0 <x <1）。我们由于粘结替代性和随机性的影响而导致量子自旋间隙的形成或破坏量子旋转间隙的构成，这是组成的函数。2。在防铁磁量子旋转链中单个地面的研究。 NIC_2O_4 ・2DMIZ和s = 1/2 cugeo_3。我们发现SP状态非常不稳定，SP状态破裂导致抗磁性交错的时刻出现，而Haldane状态对非磁性杂质的兴奋性稳定，兴奋多高达20％。（2）我们在Zn-Doped NENP上进行了ESR测量，该NENP = 1 Haldane System，S = 1 Haldane System a nonrymagnetic impuries nenp。 A new interpretation was proposed that observed signals are due to the S=1/2 broken valence bond which is subjected to the field-induced staggered internal fields produced by the underlying antiferromagnetic lattice.(3) We studiod the S=1 quasi-one dimensional Heisenbergantiferromagnet CsNiCl_3 which undergoes 3D ordering at T_N=4.8K, in order to revel the链耦合对Haldane状态的影响。我们发现，Haldane状态确实存在于T_N上方的1D阶段。我们确认了haldane状态的S = 1/2边缘状态的特征，并揭示了从量子到经典状态的交叉，这是温度和磁场的函数。较少的

项目成果

Y.Ajiro: "Impurity effect on the ground-state spin configuration in triangular lattice antiferromagnet CuFeO_2" J.Phys.Soc.Jpn.64. 3643-3646 (1995)

Y.Ajiro：“三角晶格反铁磁体 CuFeO_2 中基态自旋构型的杂质效应”J.Phys.Soc.Jpn.64。

Y.AJIRO: "ESR of the magnetic dangling bond in the Haldane state" J.phy,Soc.Jpn.66(in press). (1997)

Y.AJIRO：“Haldane 态磁悬键的 ESR”J.phy,Soc.Jpn.66（印刷中）。

M.Mehata: "Magnetic Ordering in CsCuCl_3" J.Mag.Mag.Mater. 140-144. 1986-1988 (1995)

M.Mehata：“CsCuCl_3 中的磁有序”J.Mag.Mag.Mater。

M.Takigawa: "Static properties of the S=1 one-dimensional antiferromagnet AgVP_2S_6" phys,Rer,B. 52. 12526-12529 (1995)

M.Takikawa：“S=1 一维反铁磁体 AgVP_2S_6 的静态特性”phys，Rer，B。

T.Goto: "High field magnetization of one dimensional S=1/2 trimer system 3CuCl_2・2dioxane" Physica B. 216. 294-296 (1996)

T.Goto：“一维 S=1/2 三聚体系统 3CuCl_2・2dioxane 的高场磁化”Physica B. 216. 294-296 (1996)