自旋阀结构多层膜的热稳定性

Thermal Stability of Spin-valve Multilayers

研究了Si／Ta／NiFe／Cu／NiFe／FeMn／Ta结构的自旋阀的热稳定性及层间扩散问题．高分辨电镜（HREM）观察表明，各层呈柱状晶生长．低于200°C退火能有效地提高钉扎场．高于200°C退火后，钉扎场下降，300°C时降为零．利用俄欧电子能谱仪（AES）研究了在相同的条件下制备的基片／Ta／NiFe／FeMn／Ta结构多层膜．结果表明，200°C以下时薄膜层之间主要发生沿晶界的扩散，300°C时体扩散的作用不能忽略．

Thermal stability and interface diffusion of Si/Ta/NiFe/Cu/NiFe/FeMn/Ta spin-valve have been investigated. The columnar grains are observed by high resolution electron microscopy (HREM). The pinning field increases when annealing temperature is lower than 200°C; when the annealing temperature is higher than 200°C, the pinning field decreases and other properties deteriorates; at 300°C the pinning field will be zero. From the results of Auger electron spectroscopy(AES), it can conclude that the diffusion among layers is mainly along grain boundal when the annealing temperature is lower than 200°C. The effect of bulk diffusion should be considered at 300°C.