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

目前研究的目的是利用基于分子的磁性复合体在低尺寸磁铁、特别是在连接替代链和自旋阶梯系统中实现量子自旋效应。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自旋放松（uSR）、高场磁共振（well）（well）（highfield magnetization as susceptibility and specific measurements）。我们获得了以下结果：1.对复合自旋系统组成的S=1/2子元素的量子效应的研究。（1）我们研究了在单尺寸S=1/2微调器系统、3CuCl_2·二氧ane和A_3Cu_3（PO_4）_4中的新量子自旋效应，其中三个S=1/2旋转在一个尺寸上相对地、弱耦合在一个尺寸上。我们发现了具有非统一空间结构的复合自旋系统的特性。（2）我们表现了可疑的、高场的磁性 ... More ation and NMR measurements on a S=1/2 alternating linear chain system CuCl_2·2 picolin， uniform linear chain systemCuBr_2·2 picolin and their mixed compounds CuCl_&lt;281-x）&gt; Br_<2x>·2 picolin（0&lt;x&lt;1）。我们在singlet-grod-state属性中的系统性变化是组成的一个函数，即一个形成或破坏量子自旋间隙的结果，对债券替代和随机性的影响的研究。（1）我们在Haldane和spin-Peierls系统中执行了对intimately related Quantum states的影响的系统研究， S= 1NiC_2O_4·2DMIz and S=1/2CuGeO_3。我们发现SP状态非常不稳定，并且破碎的SP状态结果在外观的反磁标记时刻，当Haldane状态稳定对抗非磁影响上升到20%时。（2） We performed the ESR measurements on the Zn-doped NeNP，S=1 Haldane system with nonmagnetic impurities。一个新的解释提出了一个新的解释，即观察到的信号应该与S=1/2断开的valence绑定，其中一个是由未知的防磁晶格产生的现场诱导的标记的内部场。（3） We studied the S=1 quasi-one dimensional HeisenbergantiferManagement magnet CsNiCl_3 which undergoes 3 D ordering at T_N = 4. 8 K，in order to revel the effect of the interchain coupling on the Haldane state。我们发现霍尔丹州确实存在于T_N以上的1D阶段。我们确认了S=1/2边缘状态的特征，揭示了一个从量子到经典状态的交叉，它是温度和磁场的两个函数。Less（低）

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