Perpendicular anisotropy and oscillatory interlayer coupling in Fe_(0.5)Co_(0.5)/Rh/Fe_(0.5)Co_(0.5) bilayers on Rh(001)

摘要

Tetragonal distortion in Fe_(0.5)Co_(0.5) alloy films grown epitaxially on Rh(001) substrates results in an easy magnetization axis perpendicular to the film plane up to the thickness of 17 ML. The distortion is supported by a Rh-overlayer; thus the strong perpendicular anisotropy can be kept when another Fe_(0.5)Co_(0.5) film is grown on top of the Rh/Fe_(0.5)Co_(0.5)/Rh(001) structure. Depending on the thickness of the Rh spacer, the top and bottom Fe_(0.5)Co_(0.5) films are either ferro- or antiferromagnetically coupled. The net magnetization of the antiferromagnetically coupled Fe_(0.5)Co_(0.5)/Rh/Fe_(0.5)Co_(0.5) bilayer switches at the field which depends on the difference between magnetizations of both the Fe_(0.5)Co_(0.5) layers. The final covering of the Fe_(0.5)Co_(0.5)/Rh/Fe_(0.5)Co_(0.5)/Rh(001) structure with Rh increases the switching field. The effect is explained by a locally enhanced magnetization in the Rh/Fe_(1-x)Co_x interfaces.