Micromagnetic Simulation of Switching Events
Micromagnetic Simulation of Switching Events
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开关事件的微磁模拟
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Fidler
中科院分区：
文献类型：
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作者：
T. Schrefl;H. Forster;D. Suess;W. Scholz;V. Tsiantos;J. Fidler
小颗粒、薄膜元件和磁性纳米线的磁开关在磁存储和磁电子器件中变得越来越重要。微磁开关事件的研究使用混合有限元/边界元法。吉尔伯特方程的空间离散化导致一个常微分方程组。其数值积分提供了在外场影响下的磁化强度的时间演化。热涨落可以用随机场来处理。反向模式极大地取决于吉尔伯特阻尼常数。将阻尼常数从α = 1减小到α ≤ 0.1将反转模式从均匀旋转改变为非均匀切换。阻尼的降低导致在圆形纳米点中形成涡旋，并导致柱状晶粒中的成核过程。如果颗粒的长度小于25 nm，则细长的Co颗粒通过旋转而反转。不可逆的切换发生较长的粒子由于形成的核的反向磁化和连续的畴壁运动。
Magnetic switching of small particles, thin film elements and magnetic nanowires becomes increasingly important in magnetic storage and magneto electronic devices. Micromagnetic switching events are studied using a hybrid finite element / boundary element method. The space discretization of the Gilbert equation leads to a system of ordinary differential equations. Its numerical integration provides the time evolution of the magnetization under the influence of an external field. Thermal fluctuations may be treated by a random field. The reversal mode drastically depends on the Gilbert damping constant. Decreasing the damping constant from α = 1 to α ≤ 0.1 changes the reversal mode from uniform rotation to inhomogeneous switching. The decrease of the damping leads to the formation of vortices in circular nanodots and to a nucleation process in columnar grains. Elongated Co particles reverse by rotation if the length of the particle is smaller than 25nm. Irreversible switching of longer particles occurs due to the formation of a nucleus of reversed magnetization and successive domain wall motion.