具有垂直各向异性(Pt/Co)_n/FeMn多层膜的交换偏置

Exchange bias with perpendicular anisotropy in (Pt/Co)_n/FeMn multilayers

采用磁控溅射方法制备了以Pt为缓冲层和保护层的具有垂直各向异性(Pt/Co)n/FeMn多层膜.研究结果表明,多层膜的垂直交换偏置场Hex和反铁磁层厚度的关系与其具有平面各向异性的交换偏置场随反铁磁层厚度变化趋势相近.随着铁磁层调制周期数的增加,垂直交换偏置场Hex相应减小,并且与铁磁层的调制周期数近似成反比关系.(Pt/Co)3/FeMn的垂直交换偏置场Hex已经达到22·3kA/m.为了进一步提高Hex,在Co/FeMn的界面插入Pt层,当Pt层厚度为0·4nm时,Hex达到最大值39·8kA/m.

In this paper, we report the observation of exchange bias in （Pt/Co）n/FeMn multilayer with perpendicular magnetic anisotropy. The samples were deposited on glass substrates by magnetron sputtering and capped with 2 nm thick Pt layer. Our results show that the relation between perpendicular exchange bias Hex of （Pt/Co）JFeMn multilayers and the thickness of antiferromagnetic layer is similar to that in the case of in-plane exchange bias. Hex is inversely proportional to the number of bilayer repeats. In the case of （Pt/Co）s/FeMn multilayers, perpendicular exchange bias Hex reachs 22.3 kA/m. With insertion of 0.4 nm Pt layer between Co layer and FeMn layer, Hex can reach 39.8 kA/m.