Effect of magnetic field on susceptibility maximum in the three-dimensional spin-12 anisotropic Heisenberg ferromagnets within Tyablikov approximation
Effect of magnetic field on susceptibility maximum in the three-dimensional spin-12 anisotropic Heisenberg ferromagnets within Tyablikov approximation
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DOI：
10.1016/j.jmmm.2008.08.050
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发表时间：
2009-02
影响因子：
2.7
通讯作者：
Y. Xiang;Yuan Chen;Qi-Zhou Chen;Wei-tong Li;Yikun Liu
中科院分区：
文献类型：
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作者：
Y. Xiang;Yuan Chen;Qi-Zhou Chen;Wei-tong Li;Yikun Liu
在Tyablikov近似下，用双时间绿色函数方法研究了磁场h对自旋S=12的三维各向异性海森堡铁磁体各向异性磁化率的影响.纵向和横向磁化率最大值的位置T和高度χ（Tm）都符合幂律：Tm−T0 <$hγ和χ（Tm）<$h−β。这里的功率（γ和β）不是临界温度Tc附近的临界指数，T0=Tc，0分别用于纵向和横向磁化率。发现功率（γ和β）强烈依赖于各向异性，这不支持指数为23的平均场幂律。讨论了纵向磁化率和横向磁化率行为差异的原因。在弱各向异性情况下，最大横向磁化率的位置在不同的磁场h下出现反常现象。
The effect of magnetic field h on the anisotropic susceptibility in a spin S=12 anisotropic three-dimensional Heisenberg ferromagnet, is studied by the double-time Green's function method within Tyablikov approximation. The position Tmand height χ(Tm) of the maxima of both longitudinal and transverse susceptibilities are all fitted satisfactory to power laws: Tm−T0∝hγ, and χ(Tm)∝h−β. Here the powers (γ and β) are not critical exponents close to the critical temperature Tc, and T0=Tc, 0 for longitudinal and transverse susceptibilities, respectively. The powers (γ and β) are found to be strongly dependent on the anisotropy, which do not support the mean-field power law with exponent to be 23. The origin of difference between the behaviors of the longitudinal and transverse susceptibility is discussed. Besides the power laws, more interesting is that in the weak anisotropy case, the position Tm⊥of the maximum transverse susceptibility displays anomalous phenomena under different magnetic field h.