末端形状对NiFe纳米薄膜磁反转动力学特性的影响

基于微磁学模拟方法研究末端形状对NiFe纳米薄膜的磁反转和自旋波本征动力学特性的调制及磁反转与自旋波模式软化间的内在联系.纳米薄膜微磁结构的相变总是伴随着某种自旋波模式的软化，软化自旋波模式空间分布预示微磁结构相变的路径.存在一临界裁剪度（h₀）.当裁剪度h<h₀时，磁振荡局域于末端边缘的EM自旋波软化诱导磁反转从磁体末端边缘磁矩失稳开始，边缘失稳区域向中央扩展形成反转畴，最后反转畴逐渐移出膜面外而实现反转.当h≥h₀时，形状各向异性导致边缘局域化模式自旋波被抑制，反转场附近一致模式自旋波的软化诱导磁体一致反转.

Effect of End Shape on Magnetization Reversal Dynamics of NiFe Nanofilm Elements

Magnetization reversal dynamics of NiFe nanofilm elements were studied with micromagnetic simulation. Magnetization reversal and spin-wave dynamic properties are effectively tuned by tailoring end shape of NiFe nanofilm elements. As magnetization reversal occurs,it is accompanied by a soft magnetic mode whose spacial symmetry determines initial steps(onset) of microscopic magnetization phase transitions path. There exists a critical tapered parameter h₀. For elements with tapering parameter h<h₀, reversal is achieved by nucleation of reversed domain at element ends and its irreversible expansion through domain wall movement toward central area of element. It is softening of edge mode that triggers magnetization reversal. For elements with h ≥ h₀, reversal is realized by quasi-uniform rotation of magnetization, which is induced by softening of fundamental mode.>