自旋阀结构中的力致磁阻效应

采用变分法研究了外应力场下铁磁单层膜、铁磁/反铁磁双层膜系统的磁化性质,进而研究了由铁磁单层膜和铁磁/反铁磁双层膜所构建的自旋阀结构中的磁电阻与外应力场之间的关系.结果表明,铁磁膜中的磁化性质与膜面内所加应力场的大小,方向密切相关,而反铁磁层的嵌入将明显地改变着铁磁层的磁矩向应力场方向磁化的行为.特别地,在应力场方向垂直于铁磁易轴情况下,当应力场日H_λ=2(K_1+K_(up)/3M)时,将发生磁化从易轴方向到应力方向的突变.为此,可采用自旋阀结构,通过其膜面内的应力场所调控的磁电阻效应,构建纳米尺度下的力磁传感器.

The magnetoresistive effect induced by stress in spin-valve structure

Using a method of free energy minimization,the magnetization properties of the ferromagnetic monolayer and ferromagnetic(FM)/antiferromagnetic(AFM)bilayer under the stress field have been investigated.And then the relation between the magnetoresistance(MR)of the Spin-Valve structure and the applied stress field was investigated.Numerical calculation shows that under the stress field,the magnetization properties of the FM monolayer is obviously different from that of FM/AFM bilayer due to that the AFM layer coupled would obviously block the magnetization of FM layer.This phenomenon resuits to M R of the Spin-Valve structure to become obvious.Specially when the direction of stress field perpendicular to the easy axis,the magnetization direction would change from the easy axis to the stress direction at that moment at thestress field equal H_λ=2(K_1+K_(up)/3M).Based on these investigations,the perfect mechanical sensor using the magnetoresistive effect induced by the stress field in nano-scale is suggested to be devised experimentally.