利用MonteCarlo(蒙特卡洛)方法结合快速傅里叶变换,模拟不同形状的偏心铁纳米环的磁特性.研究结果表明:偏心铁纳米环的磁滞回线与对称系统的磁滞回线类似,均具有双稳态,即存在明显的“vortex”态(涡旋态)与“onion”态(洋葱态).模拟结果还表明,相较于对称纳米环,偏·心铁纳米环系统具有更为复杂的过渡状态.这说明形状和结构的不对称性对铁磁纳米环的磁化行为有一定的影响.这一结果对实验研究及磁性纳米环的实际应用具有很好的指导和参考意义.
Base on the Monte-Carlo simulation and fast Fourier transformation micro-magnetism method, the effects of different shapes on decentered Fe nanorings (d-Fe-n) are studied. It is found that the magnetic hysteresis loops of both d-Fe-n and symmetric Fe-n are similar. The systems show bistable states, which means vortex-type and onion-type. However, there exists more com- plex transition state in d-Fe-n. The simulated results illustrate that the asymmetry of shape and structure has some impact on magnetic properties for Fe-n. The simulated results may have guiding significance for the experiment and the application of magnetic nanorings.