论文标题
高温下阻尼和各向异性的模型：应用于颗粒状薄膜
Model of damping and anisotropy at elevated temperatures: application to granular FePt films
论文作者
论文摘要
了解有限尺寸系统中的阻尼机理及其对温度的依赖是磁性纳米技术发展的关键步骤。在这项工作中，纳米尺寸的材料是通过原子自旋动力学建模的，从铁磁共振（FMR）模拟中提取的阻尼参数用于FEPT系统，通常用于热辅助磁记录介质（HAMR）。我们发现阻尼迅速增加接近TC，并且随着系统尺寸的减小，效果增强了，这归因于在晶界处的散射。另外，FMR方法提供了阻尼和各向异性的温度依赖性，这对于HAMR的发展很重要。半分析计算表明，在存在晶粒尺寸分布的情况下，FMR线宽可能会因不均匀线宽的损失而接近Curie温度。尽管在这项研究中已经使用了FEPT，但是当前工作中介绍的结果对于任何铁磁物质都是一般且有效的。
Understanding the damping mechanism in finite size systems and its dependence on temperature is a critical step in the development of magnetic nanotechnologies. In this work, nano-sized materials are modeled via atomistic spin dynamics, the damping parameter being extracted from Ferromagnetic Resonance (FMR) simulations applied for FePt systems, generally used for heat-assisted magnetic recording media (HAMR). We find that the damping increases rapidly close to Tc and the effect is enhanced with decreasing system size, which is ascribed to scattering at the grain boundaries. Additionally, FMR methods provide the temperature dependence of both damping and the anisotropy, important for the development of HAMR. Semi-analytical calculations show that, in the presence of a grain size distribution, the FMR linewidth can decrease close to the Curie temperature due to a loss of inhomogeneous line broadening. Although FePt has been used in this study, the results presented in the current work are general and valid for any ferromagnetic material.
