Magnetic viscosity, fluctuation fields, and activation energies (invited)
Magnetic viscosity, fluctuation fields, and activation energies (invited)
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DOI：
10.1063/1.358275
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发表时间：
1994-11
影响因子：
3.2
通讯作者：
R. Street;S. Brown
中科院分区：
文献类型：
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作者：
R. Street;S. Brown
铁磁材料磁化强度的时间依赖性最早是在世纪末描述的。随后，两种类型的机制负责时间依赖性的行为被确定，并被称为“扩散”和“波动”后效应或粘度。前者依赖于杂质原子的热致运动。后者是不可逆畴过程的热激活的结果，例如畴壁运动和反向磁化畴的成核。波动粘度或多或少地影响所有受磁滞影响的磁性材料。在20世纪40年代后期，磁粘滞性的描述在波动场（尼尔）和激活能分布（街和伍利）的发展。将描述这两种方法。磁光薄膜所表现出的时间相关现象的分析将作为激活能建模应用的一个简单例子。
Time dependence of magnetization in ferromagnetic materials was first described towards the end of the 19th century. Subsequently, two types of mechanisms responsible for time dependent behavior were identified and became known as ‘‘diffusion’’ and ‘‘fluctuation’’ after‐effect or viscosity. The former depends on thermally induced motion of impurity atoms. The latter is a consequence of thermal activation of irreversible domain processes such as domain‐wall motion and the nucleation of domains of reverse magnetization. Fluctuation viscosity affects, to a greater or smaller extent, all magnetic materials subject to hysteresis. In the late 1940s descriptions of magnetic viscosity in terms of fluctuation fields (Neel) and activation energy distributions (Street and Woolley) were developed. The two approaches will be described. An analysis of the time dependent phenomena exhibited by magneto‐optical films will be presented as a simple example of the application of activation energy modeling.