Influence of grain size and exchange interaction on the LLB modeling procedure
Influence of grain size and exchange interaction on the LLB modeling procedure
复制标题
晶粒尺寸和交换相互作用对 LLB 建模过程的影响
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
D. Praetorius
中科院分区：
文献类型：
--
作者：
C. Vogler;C. Abert;F. Bruckner;D. Suess;D. Praetorius
在真实的热辅助磁记录模拟中可靠地预测误码率是一项具有挑战性的任务。对Landau-Lifshitz-Bloch（LLB）方程进行积分可以减少确定居里温度附近的磁化动力学的计算工作量。如果我们的目标是这些动力学与从原子朗道-利夫希茨-吉尔伯特方程计算的轨迹相一致，那么我们必须仔细地对所需的温度相关的材料函数（例如零场平衡磁化以及平行和法向磁化率）进行建模。我们提出了一个广泛的研究，这些功能如何依赖于晶粒尺寸和交换相互作用。我们表明，如果参考晶粒的尺寸或交换常数被修改，材料功能可以缩放，根据改变的居里温度，产生可以忽略不计的误差。这被证明是有效的体积变化高达$pm 40$ %和变化的交换常数高达$pm 10 $ %。除了温度相关的材料曲线，计算的开关概率也同意以及分别为每个系统确定的概率。我们的研究表明，没有必要重新计算每个粒子所需的LLB输入函数。在所提出的限度内，将它们缩放到改变后的系统的居里温度就足够了。
Reliably predicting bit-error rates in realistic heat-assisted magnetic recording simulations is a challenging task. Integrating the Landau-Lifshitz-Bloch (LLB) equation can reduce the computational effort to determine the magnetization dynamics in the vicinity of the Curie temperature. If one aims that these dynamics coincide with trajectories calculated from the atomistic Landau-Lifshitz-Gilbert equation, one has to carefully model required temperature dependent material functions such as the zero-field equilibrium magnetization as well as the parallel and normal susceptibilities. We present an extensive study on how these functions depend on grain size and exchange interactions. We show that, if the size or the exchange constant of a reference grain is modified, the material functions can be scaled, according to the changed Curie temperature, yielding negligible errors. This is shown to be valid for volume changes of up to $pm 40$ % and variations of the exchange constant of up to $pm10$ %. Besides the temperature dependent material curves, computed switching probabilities also agree well with probabilities separately determined for each system. Our study suggest that there is no need to recalculate the required LLB input functions for each particle. Within the presented limits it is sufficient to scale them to the Curie temperature of the altered system.