Classical Heisenberg antiferromagnet on a garnet lattice: A Monte Carlo simulation
Classical Heisenberg antiferromagnet on a garnet lattice: A Monte Carlo simulation
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DOI：
10.1103/physrevb.63.024409
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发表时间：
2001-01-01
影响因子：
3.7
通讯作者：
Paul, DM
中科院分区：
文献类型：
--
作者：
Petrenko, OA;Paul, DM
本文采用蒙特卡罗模拟方法研究了石榴石晶格上的经典反铁磁体，试图考察几何挫折在钆镓石榴石Gd3Ga5O12 （GGG）中的作用。低温比热、磁化率、磁化率、自相关函数A(t)和中子散射函数S(Q)已经计算了几种模型，包括不同类型的磁相互作用和沿主对称轴施加外磁场的存在。一个只包含最近邻交换J(1)的模型，既没有低至最低温度的阶数，也没有显示出形成短程共面自旋结构的任何趋势。然而，该模型确实证明了磁场诱导的T以下有序类似于0.01 j(1)。为了再现实验观察到的GGG性质，模拟模型必须包括最近邻交换相互作用和偶极力。弱近邻交换相互作用的存在被发现是微不足道的。在零场中，S(Q)在反铁磁布拉格峰出现的倒易空间位置周围表现出弥漫性磁散射。
We have studied a classical antiferromagnet on a garnet lattice by means of Monte Carlo simulations in an attempt to examine the role of geometrical frustration in gadolinium gallium garnet Gd3Ga5O12 (GGG). Low-temperature specific heat, magnetization, susceptibility, the autocorrelation function A(t), and the neutron scattering function S(Q) have been calculated for several models including different types of magnetic interactions and with the presence of an external magnetic field applied along the principal symmetry axes. A model, which includes only nearest-neighbor exchange J(1), neither orders down to the lowest temperature nor does it show any tendency towards forming a short-range coplanar spin structure. This model, however, does demonstrate a magnetic field induced ordering below T similar to0.01J(1). In order to reproduce the experimentally observed properties of GGG, the simulated model must include nearest-neighbor exchange interactions and also dipolar forces. The presence of weak next-to-nearest exchange interactions is found to be insignificant. In zero field S(Q) exhibits diffuse magnetic scattering around positions in reciprocal space where antiferromagnetic Bragg peaks appear in an applied magnetic field.