High-field and high-frequency ESR study of the Haldane state formed in the ferromagnetic and antiferromagnetic alternating Heisenberg chain system(CH3)2CHNH3CuCl3
High-field and high-frequency ESR study of the Haldane state formed in the ferromagnetic and antiferromagnetic alternating Heisenberg chain system(CH3)2CHNH3CuCl3
复制标题
铁磁和反铁磁交替海森堡链体系(CH3)2CHNH3CuCl3中形成的Haldane态的高场高频ESR研究
DOI：
10.1103/physrevb.63.144428
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发表时间：
2001
影响因子：
3.7
通讯作者：
M. Tokunaga
中科院分区：
文献类型：
--
作者：
H. Manaka;I. Yamada;M. Hagiwara;M. Tokunaga
化合物（CH 3）2CHNH 3CuCl 3由铁磁和反铁磁交替的海森堡链组成，S= 1/2.根据最近的电子自旋共振（ESR）实验，在24 GHz下，一对铁磁耦合的两个自旋（表示为S^<$S1 + S2）在低于10 K时表现为一个自旋，且自旋的ε = 1，因此该化合物的磁性基态为Halfen-S态。然后，偶极-偶极相互作用和铁磁耦合的两个自旋之间的各向异性交换相互作用作为一个虚构的单离子各向异性，这消除了三重态的三倍简并。为了确认非简并三重态的能量方案，在单晶上进行了高达20 T和540 GHz的高场和高频ESR实验。在低于330 GHz和10 K的温度下，观察到三重激发态中S z=− 1 ParticipS z= 0跃迁引起的吸收。在1.7 K时，虚拟单离子各向异性的符号和值确定为D*/g μ B=− 0.24至− 0.48 T。在427.6GHz和15 T附近的外场下，在1.7K下观察到了被认为是反铁磁共振的吸收线，并形成了场致无带隙态。
The compound (CH 3) 2 CHNH 3 CuCl 3 consists of ferromagnetic and antiferromagnetic alternating Heisenberg chains with S= 1/2. According to recent electron spin resonance (ESR) experiments at 24 GHz, a pair of ferromagnetically coupled two spins, which is expressed as S^≡ S 1+ S 2, behaves as a spin with Ŝ= 1 below 10 K, and therefore the magnetic ground state in this compound is the Haldane state. Then the dipole-dipole interaction and the anisotropic-exchange interaction between ferromagnetically coupled two spins act as a fictitious single-ion anisotropy, which removes the threefold degeneracy of the triplet state. To confirm the energy scheme of the nondegenerate triplet state, high-field and high-frequency ESR experiments up to 20 T and 540 GHz were performed on the single crystals. The absorption due to the S z=− 1↔ S z= 0 transition in the triplet excited levels was observed below 330 GHz and 10 K. The sign and the value of the fictitious single ion anisotropy were determined to be D*/g μ B=− 0.24 to− 0.48 T at 1.7 K. At 427.6 GHz and under an external field near 15 T, where the field-induced gapless state is formed, the absorption line that was thought to be antiferromagnetic resonance was observed at 1.7 K.