外应力场下铁磁薄膜共振性质的理论研究

Ferromagnetic Resonance of a Thin Ferromagnetic Film under a Stress Field

根据Smith和Beljers理论方法研究了磁性薄膜在应力场作用下的铁磁共振性质.该模型选取各向同性的磁性薄膜,给出了外应力场在垂直薄膜的平面内变化时对铁磁共振性质的影响.结果表明:当外磁场处于应力场所在的平面内时,外应力的大小及方向均会影响薄膜的难易磁化轴方向.但是当外磁场处于薄膜所在的平面内时,薄膜的难易磁化轴方向则不受外应力场的影响.当应力场与外磁场均垂直膜面时,如果应力场小于某一值(4πM/3)时,共振频率在低磁场区会出现恒等于零的情况,如果应力场大于这一值时,共振频率的值会在临界场处发生突变.此外,还发现外应力的大小及其方向对于临界场和饱和场的值有着很大的影响.

The ferromagnetic resonance （FMR） of a thin ferromagnetic film under a stress field is studied by theory of Smith and Beljers. The film is considered to be isotropic thin ferromagnetic film. It showed us the effect of the stress field on the properties of ferromagnetic resonance when the stress field changed in the plane which is perpendicular to the film plane. Numerical calculations show that both the value and direction of stress field affect the direction of easy axis when the applied field and stress field is in the same plane. However, when the applied field is in the thin ferromagnetic film plane ,the direction of easy axis will be independent of the stress field. When an applied field and a stress field are perpendicular to the film plane,it is founded that the resonance frequency will retain zero for low applied fileds,otherwise,the value of the resonance frequency will present discontinuously at a critical field. In addition,it has been also found that the value of the critical field and saturation field are strongly affected by the direction and magnitude of stress fields.