EXPERIMENTAL-STUDY OF NEW TYPE PHASE-TRANSITION IN TRIANGULAR LATTICE ANTIFERROMAGNET VCL2
EXPERIMENTAL-STUDY OF NEW TYPE PHASE-TRANSITION IN TRIANGULAR LATTICE ANTIFERROMAGNET VCL2
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DOI：
10.1143/jpsj.56.4027
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发表时间：
1987-11-01
影响因子：
1.7
通讯作者：
SHIRANE, G
中科院分区：
文献类型：
--
作者：
KADOWAKI, H;UBUKOSHI, K;SHIRANE, G
使用准二维反铁磁体 VCl 2 通过中子散射实验研究了三角晶格上海森堡反铁磁体的关键性质。结果发现，VCl 2 显示出二维和三维模型的特征临界行为。稍高于 T N 时，χ (Q) 的线形被发现由 Ornstein-Zernike 形式 (κ 2+ q 2)− 1 表示。这表明二维模型中预测的磁点缺陷的存在。测得的临界指数为β= 0.20±0.02、γ= 1.05±0.03、ν= 0.62±0.05，与三维SO (3) 系统的理论工作一致。在 T N1= 35.88±0.01 K 和 T N2= 35.80±0.01 K 处发现了由于小伊辛各向异性而导致的连续相变。还确定了远低于 T N 的自旋波的自旋结构和色散关系。
Critical properties of a Heisenberg antiferromagnet on a triangular lattice are investigated experimentally using a quasi-two-dimensional antiferromagnet VCl 2 by means of neutron scattering. It is found that VCl 2 shows characteristic critical behaviors of two and three dimensional models. A little above T N, the line shape of χ (Q) is found to be represented by the Ornstein-Zernike form (κ 2+ q 2)− 1. This suggests the existence of magnetic point defects which were predicted in the two dimensional model. The measured critical exponents are β= 0.20±0.02, γ= 1.05±0.03, and ν= 0.62±0.05, in agreement with the theoretical work for three dimensional SO (3) systems. Successive phase transitions due to a small Ising anisotropy were found at T N1= 35.88±0.01 K and T N2= 35.80±0.01 K. The spin structure and the dispersion relation of the spin wave well below T N are also determined.