铁磁共振法测磁各向异性

Measurement of magnetic anisotropy by ferromagnetic resonance

采用铁磁共振方法,研究了铁磁/反铁磁双层膜系统中,因交换耦合以及磁晶各向异性而产生的有效各向异性场.结果表明被测系统有无交换偏置场以及其正负号性质等均能在共振谱中得到辨析.结果还显示沿着不同结晶方向施加外磁场,共振场的行为与磁晶各向异性以及铁磁/反铁磁交换耦合作用而诱发的单向各向异性等密切相关.将共振频率的变化看成外磁场(包括其方向和大小)的函数,研究得到了单向各向异性,立方各向异性等对共振频率的影响,并同实验结果做了很好的比较.

The effective magnetic field caused by exchange coupling between a ferromagnetic and an antiferromagnetic bilayer and its magnetic anisotropy have been investigated by means of ferromagnetic resonance.It was shown that the exchange bias phenomenon occurrence and its positive or negative characteristic for ferromagnetic /antiferromagnetic bilayer can be identified from its magnetic resonance spectrum.In addition,when the field was applied along different crystalline directions,the behavior of magnetic resonance field will be changed,and is closely dependent on the magnetocrystalline anisotropy and unidirectional anisotropy induced by the interface coupling in ferromagnetic /antiferromagnetic bilayer.Anomalies in the ferromagnetic resonance frequency studied as functions of applied field,including its orientation and strength,are interpreted as evidence for the four fold anisotropy and unidirectional anisotropy.Our conclusions are in good agreement with the related experiments.