反铁磁耦合软磁/硬磁双层膜体系的交换弹性反磁化特性

The Exchange-Spring Magnetization Reversal Characteristic of the Antiferromagnetically Exchange Coupled Soft / Hard Magnetic Bilayer

基于微磁学理论研究了软磁/硬磁反铁磁交换耦合双层结构体系的反磁化特性,利用一维原子链模型模拟了其反磁化过程。研究表明:当考虑了软磁层的磁晶各向异性能后,随着软磁层厚度的增大,交换弹性反磁化过程从可逆过程转变为不可逆过程。存在一个临界的软磁层厚度tc,当软磁层厚度ts<tc时,交换弹性反磁化过程为可逆过程;而当ts>tc时,交换弹性反磁化过程为不可逆过程。形核场Hb随软磁层厚度的变化仅当体系的反磁化过程为可逆的交换弹性反磁化过程时才满足经验公式Hb=Hb0/tsn。

Based on the micromagnetie theory, the magnetization reversal characteristic of the antiferromagne- tically exchange coupled soft/hard magnetic bilayer was studied. The magnetization reversal processes of the bilayer system were simulated based on the one dimensional atomic chain model. The results show that when the magnetic a- nisotropy of soft layer is taken into account, the change of the soft layer thickness may lead to a transition from the re- versible exchange-spring process to the irreversible process. There is a crossover point to, for the bilayer system, when the soft layer thickness ts〈tc, the magnetization reversal process exhibits typical reversible magnetic exchange- spring behavior. However as ts〉tc, the process becomes irreversible. The dependences of the bending field on the soft layer thickness cannot be adequately described by the simple formula Hb = Hbo/ts＂.