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采用磁控溅射方法制备了Ta/NiFe/非磁金属隔离层/FeMn多层膜,研究了交换耦合场Hex相对于非磁金属隔离层厚度的变化关系.实验结果表明:随非磁金属隔离层厚度的增加,以Bi和Ag为隔离层的Hex薄膜急剧下降,以Cu为隔离层的薄膜的Hex下降较缓慢.对Cu而言,它的晶体结构与NiFe层晶体结构相同且晶格常数相近,Cu层以及FeMn层都可以相继外延生长,FeMn层的(111)织构不会受到破坏,因此,Hex随Cu沉积厚度增加缓慢下降.对Ag而言,虽然它的晶体结构与NiFe层晶体结构相同,但晶格常数相差较大,Ag层以及FeMn层都不可能外延生长,FeMn层的织构将会受到破坏,Hex随Ag沉积厚度增加迅速下降.对Bi而言,不仅它的晶体结构与NiFe层的不同,而且晶格常数相差也较大,同样,Bi层以及FeMn层也不可能外延生长,FeMn层的织构也会受到破坏,因此,Hex也随Bi沉积厚度增加迅速下降.但是,X射线光电子能谱研究表明:极少量的表面活化原子Bi沉积在NiFe/FeMn界面时,会上浮到FeMn层表面,因而Hex下降很少.
The Ta / NiFe / non-magnetic metal separator / FeMn multilayers were prepared by magnetron sputtering and the relationship between the exchange coupling field Hex and the thickness of the non-magnetic metal separator was investigated. The experimental results show that with the non-magnetic metal separator The increase of layer thickness and the decrease of Hex film with Bi and Ag as the isolation layer, the decrease of Hex of the film with Cu as the isolation layer is slower. For Cu, its crystal structure is the same as the crystal structure of NiFe layer and the lattice constant , The Cu and FeMn layers can all be epitaxially grown and the (111) texture of the FeMn layer will not be damaged. Therefore, Hex decreases slowly with the increase of the deposition thickness of Cu. Although its crystal structure is similar to that of the NiFe layer The crystal structure is the same, but the lattice constant is quite different, it is impossible for the Ag layer and the FeMn layer to be epitaxially grown, the texture of the FeMn layer will be destroyed, and Hex rapidly declines with the increase of the Ag deposition thickness. The crystal structure is different from the NiFe layer, and the lattice constant is also large. In the same way, the Bi layer and the FeMn layer can not be epitaxially grown, and the texture of the FeMn layer is also damaged. Therefore, as the Bi deposition thickness increases rapidly, Hex also increases rapidly However, X-ray photoelectron spectroscopy studies have shown that: When a small amount of surfactant deposited on the Bi atoms NiFe / FeMn interface, FeMn layer will float to the surface, and therefore little reduction in Hex.