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通过研究外应力场下铁磁多层膜系统中的自旋结构,讨论了系统磁电阻对外应力的依赖关系.结果表明,外应力能够诱发磁电阻效应,且其磁电阻紧密依赖于外应力的大小和方向.一般地对铁磁性层间耦合,其磁电阻与外应力之间的关系紧密地依赖于两铁磁层的磁致伸缩系数以及磁晶各向异性之差异.具体地,大小一定的外应力由磁易轴向磁难轴旋转的过程中,磁电阻先缓慢增大后急剧减小,在磁难轴附近变化较敏锐,并出现峰值.外应力方向一定时,磁电阻随应力的增大先敏锐增强后缓慢减小,且应力方向偏离磁易轴越远,变化趋势越显著.特别地,当外应力完全垂直于磁易轴时,应力大小的变化会引起磁电阻翻倍.而外应力场介于8πM/5≤Hλ≤18πM/5时,磁电阻会随应力的旋转单调上升,并在磁难轴附近急剧增强,产生GMR效应;对反铁磁性层间耦合,其GMR效应对应力大小和方向的响应近似地相反于铁磁性层间耦合情形.
By studying the spin structure in the ferromagnetic multilayer system under external stress field, the dependence of system MR on external stress is discussed. The results show that the external stress can induce MR effect and the MR resistance is closely dependent on the external stress Size and orientation of the ferromagnetic layer, the relationship between the magnetoresistance and the external stress generally depends strongly on the magnetostriction coefficient and the magnetocrystalline anisotropy of the two ferromagnetic layers, and in particular, the size must be constant Of external stress in the process of magnetic easy axial rotation of the magnetic axis, the magnetic resistance slowly increases first and then decreases sharply in the vicinity of the magnetic hard axis changes more sensitive and peaked.When the external stress direction is certain, the magnetic resistance with stress Increases sharply and then slowly decreases, and the direction of stress deviates more from the magnetic easy axis, the more obvious the change trend.Especially when the external stress is completely perpendicular to the magnetic easy axis, the change of the size of the stress will cause the magnetic resistance to double When the external stress field is between 8πM / 5≤Hλ≤18πM / 5, the magnetic resistance monotonically increases with the stress rotation and increases sharply near the magnetic hard axis, resulting in GMR effect. For the antiferromagnetic interlayer coupling, the GMR effect on the size of the stress and direction of the ring Should be approximately opposite to the ferromagnetic interlayer coupling case.