EXPERIMENTAL VERIFICATION AND CONTROL OF SPIN LIQUID STATE

自旋液态的实验验证与控制

基本信息

批准号：
09440139
负责人：
AJIRO Yoshitami
金额：
$ 1.41万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

The purpose of this project is to verify experimentally and control the possible spin liquid syate which is theoretically predicted to be exist in some low dimensional magnets, due to the quantum spin ejjects and spin frustration effects. For this purpose, we synthesized a various kind of model quantum systems and applied various complementary techniques, including advanced crystal preparation, nuclear Magnetic resonance, electron spin resonance, neutron scattering, muon spin relaxation, high field magnetization as well as sysceptobility and specific heat measurements, in cooperation with many other research groups. A summary of our research is as follows.1) Synthesis of the model substances such as S=1/2 antiferromagnetic chain Cu (C_6H_7N)_2Br_2, S=1/2 bond alternating chain Cu (C_6H_7N)_2Cl_2, S=1/2 spin ladder Cu_2(C_5H_<12>N_2)_2Cl_4, Cu_2 (C_5H_<12>N_2) _2Bra_4 and so on.2) Study of quantum effects of composite spin systems composed of S=1/2 subelements.For example, we performed high-frequency ESR study up to 800GHz of trimerized chain system 3CuCI_2-2dx, in which ferromagnetic trimers consisting of three S=1/2 spins coupled antiferromagnetically in one dimension. We observed peculiar behaviors characteristic of composite spin. system with nonuniform spatial structure.3) Control of quantum spin-gappped phase.We explored the possible induced-phase transition in the quantum singlet ground state systems with spin gap by applying high magnetic field or by doping impurity ions. For example, we observed successive phase transitions at three restricted field regions up to 40T in the S=2/3 dimerized system Cs_3Cr_2Cl_3.

该项目的目的是通过实验验证并控制理论上可能存在于某些低维磁铁中的可能旋转液体结石，这是由于量子旋转的射体和旋转挫败感的效果。为此，我们合成了各种模型的量子系统，并应用了各种互补技术，包括先进的晶体制备，核磁共振，电子自旋共振，中子散射，MUON自旋松弛，高场磁化以及与许多其他研究组合作。我们的研究的摘要如下。1）合成模型物质，例如s = 1/2抗铁磁链Cu（C_6H_7N）_2BR_2，s = 1/2键交替链Cu（C_6H_7N）_2cl_2，_2cl_2，s = 1/2 Spin ladder cu_2 cu_2 cu_2（c_5h__2）（C_5H_ <12> N_2）_2BRA_4等。2）研究的研究由S = 1/2子元素组成的复合自旋系统的量子效应。例如，我们进行了高频ESR研究，高频ESR研究高达800GHz，最多需要修剪的链系统3CUCI_2-2DX，其中Ferromagnetic spins spins cc/spins consect cc/2 = 1/2在一个维度上进行反铁磁性。我们观察到复合自旋的特殊行为。 3）控制量子旋转相位相位的系统。我们通过施加高磁场或掺杂杂质离子来探索带有自旋间隙的量子单重态基态系统中可能的诱导相跃迁。例如，我们在s = 2/3二聚化系统CS_3CR_2CL_3中观察到三个限制的场区域的连续相变。