Magnetic phase transition induced by bond randomness in mixed alternating Heisenberg chains (CH 3 ) 2 CHNH 3 Cu(Cl x Br 1-x ) 3 observed by magnetization process
Magnetic phase transition induced by bond randomness in mixed alternating Heisenberg chains (CH 3 ) 2 CHNH 3 Cu(Cl x Br 1-x ) 3 observed by magnetization process
复制标题
通过磁化过程观察到混合交替海森堡链 (CH 3 ) 2 CHNH 3 Cu(Cl x Br 1-x ) 3 中键随机性诱导的磁性相变
DOI：
10.1103/physrevb.66.064402
复制
发表时间：
2002
影响因子：
3.7
通讯作者：
T. Goto
中科院分区：
文献类型：
--
作者：
H. Manaka;I. Yamada;H. Mitamura;T. Goto
混合磁性系统 (CH 3 ) 2 CHNH 3 Cu(Cl x Br - x ) 3 是霍尔丹态和单线态二聚体中键随机性影响的实验研究的良好候选者。我们研究了这些具有不同 x 值（0≤x<1）的混合化合物在 1.7 K、高达 41 T 的外场下的磁化过程。结果，在 0.87≤x≤1 的情况下，证实了有限能隙的存在，而在 0.44<x<0.87 的情况下，检测到了典型的自旋随角跃迁，表明不存在能隙。根据自旋随角异色跃迁场随 x 的变化，发现自旋期望值 (S z i ) 在 x≃0.71 处达到最大值，此时键随机性最高。另一方面，当0≤x≤0.44时，磁化曲线显示出不明显的增加，这使得很难确定是否存在能隙。
Mixed magnetic systems (CH 3 ) 2 CHNH 3 Cu(Cl x Br - x ) 3 are good candidates for experimental studies of the effect of bond randomness in both the Haldane state and the singlet dimer state. We investigated the magnetization process in these mixed compounds with various values of x (0≤x<1) under an external field up to 41 T at 1.7 K. As a result, the existence of a finite energy gap was confirmed for 0.87≤x≤1, while a typical spin flop transition, which indicates absence of the energy gap, was detected for 0.44<x<0.87. From the variation of the spin flop transition field with x, the expected value of spins (S z i ) was found to reach its maximum at x≃0.71, the point at which bond randomness is highest. For 0≤x≤0.44, on the other hand, the magnetization curves showed indistinct increases, which made it difficult to ascertain whether the energy gap exists.