论文标题
各向异性驱动的磁化磁化逆转：蒙特卡洛研究
Anisotropy driven reversal of magnetisation in Blume-Capel ferromagnet: A Monte Carlo study
论文作者
论文摘要
通过Monte Carlo模拟使用Metropolis算法研究了二维自旋-1 Blume-Capel Ferromagnet。从初始有序旋转构型开始，在沿相反方向上应用的磁场（$ h $）的情况下研究了磁化的逆转。详细研究了随着单位各向异性的强度的逆转时间的变化。观察到指数依赖性。发现平均反转时间的系统变化，具有正各向异性和负各向异性。观察到平均宏观逆转时间是线性取决于适当定义的微观反转时间的。发现逆转后，饱和磁化$ m_f $取决于各向异性$ d $的强度。获得了一个有趣的缩放关系，$ | m_f | \ sim | h |^βf（d | h |^{ - α}）$具有$ f（x）= \ frac {1} {1+e^{（x-a）/b}} $的缩放函数。 $ s_i^z = 0 $的密度的时间演变（被所有$ s_i^z =+1 $包围）被指数衰减。 $ s_i^z = -1 $的平均密度的增长已安装在函数$ρ_{ - 1}（t）（t）\ sim \ frac {1} {a+e^{（t_c-t）/c}} $中。特征时间显示$ t_c \ sim e^{ - rd} $，在$ d = 1.5 $时观察到指数下降速率的交叉。已发现亚稳态的分数可以遵守Avrami定律。
The two dimensional Spin-1 Blume-Capel ferromagnet is studied by Monte Carlo simulation with Metropolis algorithm. Starting from initial ordered spin configuration the reversal of magnetisation is investigated in presence of a magnetic field ($h$) applied in the opposite direction. The variations of the reversal time with the strength of single site anisotropy are investigated in details. The exponential dependence was observed. The systematic variations of the mean reversal time with positive and negative anisotropy was found. The mean macroscopic reversal time was observed to be linearly dependent on a suitably defined microscopic reversal time. The saturated magnetisation $M_f$ after the reversal was noticed to be dependent of the strength of anisotropy $D$. An interesting scaling relation was obtained, $|M_f| \sim |h|^βf(D|h|^{-α})$ with the scaling function of the form $f(x)= \frac{1}{1+e^{(x-a)/b}}$. The temporal evolution of density of $S_i^z=0$ (surrounded by all $S_i^z=+1$) is observed to be exponentially decaying. The growth of mean density of $S_i^z=-1$ has been fitted in a function $ρ_{-1}(t) \sim \frac{1}{a+e^{(t_c-t)/c}}$. The characteristic time shows $t_c \sim e^{-rD}$ and a crossover in the rate of exponential falling is observed at $D=1.5$. The metastable volume fraction has been found to obey the Avrami's law.
