Microstructures of NiFe/nonmagnetic metal spacer/FeMn films and their influences on exchange coupling  

作　　者：李明华 于广华 朱逢吾 何珂 赖武彦 

机构地区：[1]Department of Materials Physics, University of Science and Technology Beijing, Beijing 100083, China [2]Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China

出　　处：《Science China(Technological Sciences)》2003年第6期645-653,共9页中国科学（技术科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.50271007);the Natural Science Foundation of Beijing(Grant No.2012011).

摘　　要：Ta/NiFe/nonmagnetic metal spacer/FeMn films were prepared by magnetron sputtering. The dependences of the exchange coupling field (Hex) between an antiferromagnetic FeMn layer and a ferromagnetic NiFe layer on the thickness of nonmagnetic metal spacer layers were system-atically studied. The results show that the Hex dramatically decreases with the increase in the thicknesses of Bi and Ag spacer layers. However, it gradually decreases with the increase in the thickness of a Cu spacer layer. For a Cu space layer, its crystalline structure is the same as that of NiFe and the lattice parameters of them are close to each other. The Cu layer and FeMn layer will epitaxially grow on the NiFe layer in succession, so the (111) texture of the FeMn layer will not be damaged. As a result, the Hex gradually decreases with the deposition thickness of a Cu layer. For an Ag space layer, its crystalline structure is the same as that of NiFe, but its lattice parameter is very different from that of NiFe. Thus, neither an Ag nor an FeMn layer will epitaxially grow on the NiFe layer and the (111) texture of the FeMn layer will be damaged. The Hex rapidly decreases with the increase in the deposition thickness of an Ag layer. For a Bi spacer layer, not only its crystalline structure but also its lattice parameter is greatly different from that of NiFe. For the same reason, the Bi and FeMn layer cannot epitaxially grow on the NiFe layer. The texture of the FeMn layer will also be damaged. Therefore, the Hex rapidly decreases with the increase in the deposition thick-ness of a Bi layer as well. However, the research result of X-ray photoelectron spectroscopy indi-cates that a very small amount of surfactant Bi atoms will migrate to the FeMn layer surface when they are deposited on the NiFe/FeMn interface. Thus, the Hex will hardly decrease.Ta/NiFe/nonmagnetic metal spacer/FeMn films were prepared by magnetronsputtering. The dependences of the exchange coupling field (H_(ex)) between an antiferromagneticFeMn layer and a ferromagnetic NiFe layer on the thickness of nonmagnetic metal spacer layers weresystematically studied. The results show that the H_(ex) dramatically decreases with the increase inthe thicknesses of Bi and Ag spacer layers. However, it gradually decreases with the increase inthe thickness of a Cu spacer layer. For a Cu space layer, its crystalline structure is the same asthat of NiFe and the lattice parameters of them are close to each other. The Cu layer and FeMn layerwill epitaxially grow on the NiFe layer in succession, so the (111) texture of the FeMn layer willnot be damaged. As a result, the H_(ex) gradually decreases with the deposition thickness of a Culayer. For an Ag space layer, its crystalline structure is the same as that of NiFe, but its latticeparameter is very different from that of NiFe. Thus, neither an Ag nor an FeMn layer willepitaxially grow on the NiFe layer and the (111) texture of the FeMn layer will be damaged. TheH_(ex) rapidly decreases with the increase in the deposition thickness of an Ag layer. For a Bispacer layer, not only its crystalline structure but also its lattice parameter is greatly differentfrom that of NiFe. For the same reason, the Bi and FeMn layer cannot epitaxially grow on the NiFelayer. The texture of the FeMn layer will also be damaged. Therefore, the H_(ex) rapidly decreaseswith the increase in the deposition thickness of a Bi layer as well. However, the research result ofX-ray photoelectron spectroscopy indicates that a very small amount of surfactant Bi atoms willmigrate to the FeMn layer surface when they are deposited on the NiFe/FeMn interface. Thus, theH_(ex) will hardly decrease.

关 键 词：NiFe/FeMn  NONMAGNETIC metal spacer  exchange coupling field (Hex)  lattice match  X-ray diffraction (XRD). 

分 类 号：O484.4[理学—固体物理]