外应力场下双层铁磁薄膜中的铁磁共振性质

Ferromagnetic resonance in ferromagnetic bilayer films under the stress anisotropy

用铁磁共振方法得到了双层铁磁薄膜的色散关系解析表达式.发现共振场依赖于层间耦合强度和应力场.假定层间为反铁磁性耦合,且铁磁层A有较强的平面内各向异性.随着外磁场的增强,铁磁层B中的磁化强度突然由最初的反平行转为平行,从而导致色散曲线的阶跃,并且发现光学模阶跃幅度比声学模大.随着应力场的增强,B层中磁化强度反转所需的外磁场减弱.此外,在不同的交换耦合强度和应力场下,光学模共振场对外磁场方向的依赖性较强.

The ferromagnetic resonance （FMR） technique has been used to investigate the properties of ferromagnetic/nonmagnetic /ferromagnetic systems. We derived the FMR dispersion relation, taking into account the competition between the indirect interlayer coupling and stress anisotropy. In this case,one of the layers A has a strong in-plane anisotropy compared with the coupling strength and the in-plane anisotropy of the other layer B. As the applied field increases,magnetization of layer B may suddenly switch from the antiparallel configuration to the saturated state. The discontinuities are more important for the optical than for the acoustic modes. For the optical mode,the effect of interlayer coupling and stress anisotropy on the HR vs φ^H curves is more apparent.