Temperature dependence of the threshold magnetic field for nucleation and domain wall propagation in an inhomogeneous structure with grain boundary
Temperature dependence of the threshold magnetic field for nucleation and domain wall propagation in an inhomogeneous structure with grain boundary
复制标题
具有晶界的非均匀结构中成核和畴壁传播的阈值磁场的温度依赖性
DOI：
10.1103/physrevb.94.054430
复制
发表时间：
2016
影响因子：
3.7
通讯作者：
and Seiji Miyashita
中科院分区：
文献类型：
--
作者：
Sasmita Mohakud;Sergio Andraus;Masamichi Nishino;Akimasa Sakuma;and Seiji Miyashita
为了研究烧结磁体的矫顽力对温度的依赖性，研究了在晶界处的成核和畴壁传播作为磁体中的磁化反转现象的速率确定过程，所述磁体由经由软磁材料的晶界接触的大块硬磁性颗粒组成。这些系统已经在零温下的连续介质模型中进行了解析研究[A.佐久间，J·玛格·玛格·马特。1016/0304 - 8853（90）90162-J]。本文利用有限温度下的随机Landau-Lifshitz-吉尔伯特方程研究了温度依赖性。特别是，成核和畴壁传播的阈值场作为不同温度下的软，硬磁体的磁相互作用和各向异性的比率的函数。结果表明，畴壁扩展的阈值场对热涨落是鲁棒的，而形核的阈值场是脆弱的。所观察到的温度依赖性的微观机制进行了讨论。
In order to study the dependence of the coercive force of sintered magnets on temperature, nucleation and domain wall propagation at the grain boundary are studied as rate-determining processes of the magnetization reversal phenomena in magnets consisting of bulk hard magnetic grains contacting via grain boundaries of a soft magnetic material. These systems have been studied analytically for a continuum model at zero temperature [A. Sakuma , J. Magn. Magn. Mater. 84, 52 (1990)JMMMDC0304-885310.1016/0304-8853(90)90162-J]. In the present study, the temperature dependence is studied by making use of the stochastic Landau-Lifshitz-Gilbert equation at finite temperatures. In particular, the threshold fields for nucleation and domain wall propagation are obtained as functions of ratios of magnetic interactions and anisotropies of the soft and hard magnets for various temperatures. It was found that the threshold field for domain wall propagation is robust against thermal fluctuations, while that for nucleation is fragile. The microscopic mechanisms of the observed temperature dependence are discussed.