Magnetic Ordering Process in Geometrically Frustrated Systems

几何受挫系统中的磁排序过程

基本信息

批准号：
06452059
负责人：
MEKATA Mamoru
金额：
$ 4.61万
依托单位：
Fukui University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06452059/
关键词：
Geometrical frustration 3 dimensional competition Ground state Spin fluctuations Spin freezing Neutron spin echo muSR NMR フラストレーション三角格子かごめ格子部分無秩序構造 RVB 磁気相図

项目摘要

The results of the research on geometrically frustrated systems are as follow.1) Magnetic ordering process in CsNiCl_3-type compoundsNMR spectra of CsFeBr_3 and RbFeBr_3 turn to powder patterns in certain temperature range just below T_N indicating randomness of mutual phases of adjacent magnetic layrs with 120ﾟ structure. But it is not yet known whether the randomness is static or dynamic. It was also found that NMR signal in the intermediate temperature phase of CsCoBr_3 due to fluctuations of the internal field caused by domain wall solitons which was revealed to survive down to the low temperature phase. The magnetic structure at high magnetic fields of CsNiCl_3 was identified to be as predicted bu theory.2) Crystalline field splitting and magnetic phase diagram in FeI_2An electronic transition associated with the crystalline field splitting was observed around 100K by ESR and muSR in FeI_2. Measurements of magnetization on FeI_2 in intense magnetic fields revealed the absence of t … More he tricritical point speculated previously which may be related to the first order transition at T_N.3) Impurity effect on spin symmetry in CuFeO_2Al doping to CuFeO_2 was found to change the Ising spin system to a Heisenberg system, but the experimental results concerning the crossover concentration as well as the coexistence of both systems are not yet consistent with each other.4) Ground state of three dimensional competing system with corner shared tetrahedronsRemarkable spin fluctuations probed by muon spin relaxation survive down to 0.1K in SrCr_8Ga_4O_<19> with Kagome lattice composed of corner shared tetrahedrons, whereas neutron spin echo revealed the spin freezing below 3.5K consistently with the field cooling effect observed in the magnetic susceptibility. Similarly spin freezing was observed below 2K by means of muSR in Y (Sc) Mn2 although no anomaly in the relaxation time of NMR has been detected by NMR down to 0.07K.Thus in strongly frustrated systems with corner shared tetrahedronsan spins freeze at low temperatures. The spin freezin in the geometrically frusatrated systems has different features from that in random spin systems. The elucidation of the difference is a future problem. Less

关于几何挫败系统的研究结果如下。1）CSNICL_3型CSFEBR_3和RBFEBR_3的CSNICL_3型化合物SNMR光谱中的磁性顺序的结果转向T_N以下的某些温度范围，表明与120架结构的相邻磁性Layr的相互磁性相邻相互阶段的随机性。但是尚不清楚随机性是静态还是动态性。还发现，由于域壁固体引起的内部磁场的波动，NMR信号在CSCOBR_3的中间温度阶段中，这被发现可以生存至低温阶段。 CSNICL_3的高磁场上的磁结构被确定为预测的BU理论。2）FEI_2中的ESR和MOSR在FEI_2AN电子过渡中的晶体场分裂和FEI_2AN电子过渡中与Crystalline Field分裂相关的磁相图。在强烈的磁场上对FEI_2进行磁化的测量表明，缺乏……更多的是先前提出的更严重的点，这可能与t_n.n.3）在t_n.3.3）中对CUFEO_2的杂质效应有关CUFEO_2AL掺杂到Cufeo_2中的杂质效应，从而使Ising旋转系统不断变化，但同时又是浓缩的，但同时进行了实验，并具有实验性的结果。这两个系统尚未彼此一致。4）三维竞争系统的基态，角落共享四面体标记的可旋转旋转波动探测，穆恩旋转放松探测的旋转波动在srcr_8ga_4o_ <19>中降至0.1k，与kagome lattice corter corter corter there there spine spins spins spin 3. srcr_8ga_4o_ <19>相互启动。在磁敏感性中观察到。同样，通过在y（sc）MN2中，通过MUSR在2K以下观察到自旋冷冻，尽管NMR在NMR的松弛时间中未在NMR的松弛时间下降到0.07K。在几何型系统中的自旋冻结与随机自旋系统中具有不同的特征。差异的阐明是未来的问题。较少的