采用蒙特卡罗方法讨论了硬磁-软磁双层膜中的磁化行为与双层膜中磁参量之间的关系.结果表明:硬磁-软磁双层膜中剩余磁化强度随硬磁层或软磁层厚度的增加呈单调性减小或增大,相应的矫顽场随硬磁层或软磁层厚度的增加近似呈单调性增大或减小;而其磁能积的变化是非单调性的,存在磁能积极大值点,该极大值点依赖于硬磁-软磁层的厚度比、各自的饱和磁化强度和单轴各向异性等;硬磁-软磁双层膜的磁化总是从膜边界向膜中间推进,最终带动难轴方向的边界畴转变,且软磁层磁化先于硬磁层,但在软磁层厚度小于临界尺寸的情况下,软磁层与硬磁层的磁化反转趋于同步.
The magnetization behavior and energy product of the hard-soft nanocomposite bilayer system are discussed by means of Montecarlo method.It is found that the remanent magnetization decreases or increases if the thickness of hard or soft layer is increased,respectively.However,the coercivity increases or decreases when the thickness of hard or soft layer increases,respectively.The variation of energy product is nonmonotonic and the maximum value depends on the ratio of the hard layer thickness to soft layer thickness,saturation magnetization,uniaxial anisotropy and so on.The magnetization reversal process always begins from domain boundary,then the middle of the film,and finally the boundary domain along the hard axis.In general,soft layer reverses before hard layer.When the thickness of the soft phase is smaller than a critical value,the magnetization reversal processes for both the hard layer and the soft layer happen almost at the same time.