具有分隔层Bi的反铁磁/铁磁双层薄膜间的短程交换耦合

Short-range exchange coupling in the AFM/FM bilayers with a spacer layer

用磁控溅射方法制备了NiFeⅠ FeMn Bi NiFeⅡ 薄膜 ,研究了反铁磁薄膜FeMn与铁磁薄膜NiFeⅠ 及NiFeⅡ 间的交换偏置场Hex相对于分隔层Bi厚度的变化 .发现随分隔层Bi厚度的增加 ,FeMn与NiFeⅠ 间的交换偏置场Hex1 几乎不变 ,FeMn与NiFeⅡ 间的交换偏置场Hex2 急剧减小 .当Bi的厚度超过 0 6nm时 ,FeMn与NiFeⅡ 之间的交换偏置场从 6 92 5下降为 0 876kA·m- 1 .x射线光电子能谱 (XPS)分析表明 ,沉积在FeMn NiFeⅡ 界面的Bi并没有全部停留在界面处 ,至少有部分偏聚到NiFeⅡ

The NiFe (I) /FeMn/Bi/NiFe (II) films were prepared by magnetron sputtering. The Bi thickness dependences of H-ex between antiferromagnetic FeMn film and both ferromagnetic NiFe (I) film and NiFe (II) film were studied systematically. With the increase of the thickness of the Bi film, the exchange bias field H-ex2 between the FeMn and NiFe (I) is almost invariable; however H-ex2 between FeMn and NiFeII decreases dramatically. H-ex2 decreases from 6.925 to 0.876kA(.)m(-1) while Bi film thickness is larger than 0.6 nm. Bi atoms do not stay fully at the interface between FeMn and NiFe (II) but at least partially segregate onto the NiFe (II) surface.