Anomalous spin diffusion in ferromagnetic spin systems
Anomalous spin diffusion in ferromagnetic spin systems
复制标题
铁磁自旋系统中的反常自旋扩散
DOI：
10.1016/0022-3697(67)90071-6
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发表时间：
1967
影响因子：
4
通讯作者：
K. Kawasaki
中科院分区：
文献类型：
--
作者：
K. Kawasaki
研究了居里点附近顺磁区铁磁海森堡自旋系统的自旋扩散问题，采用了处理在临界点附近出现异常峰的输运系数的方法。发现传统的临界减速理论对这一问题是不充分的，并给出了广义扩散系数的自洽处理。结果表明，在居里点附近，顺磁区的扩散常数以x−(14)而不是x−1的形式消失，其中x为磁化率。这一特性的原因是讨论了分子扩散在临界混合物，其中传统理论似乎持有多少相关的问题。该理论还预测了自旋扩散系数对施加扰动的波矢量和频率的强烈依赖。
The problem of spin diffusion in ferromagnetic Heisenberg spin systems in paramagnetic region near the Curie point is studied using the method developed for treating the transport coefficients exhibiting anomalous peaks near the critical point. The conventional theory of the critical slowing-down is found to be inadequate for this problem, and the self-consistent treatment for the generalized diffusion coefficient is presented. The result predicts that the diffusion constant in paramagnetic region vanishes like x−(1 4) instead of x− 1 near the Curie point where x the magnetic susceptibility. The reason for this peculiarity is discussed in relation to the somewhat related problem of the molecular diffusion in critical mixtures where the conventional theory seems to hold. The theory also predicts a strong dependence of the spin diffusion coefficient on the wave vector and frequency of an applied disturbance.