Perpendicular magnetic anisotropy and magnetic proximity effect in Pt1-δFeδ/Co multilayer films

The perpendicular magnetic anisotropy (PMA) and magnetization in Pt1-delta Fe delta/Co (delta=0, 0.017,0.04 and 0.06) multilayer films have been investigated. It is found that, on adding a small amount of Fe into the Pt layers, Pt/Co multilayer films maintain well-defined PMA at both 5 and 300 K along with significantly enhanced magnetization even at room temperature, which is far greater than the Curie temperature of Pt1-delta Fe delta dilute alloys. Further study demonstrates that the large enhancement of the magnetization in the Fe doped Pt/Co multilayers at 300 K arises from the bulk moment of the Pt1-delta Fe delta layers at the interface region, where the ferromagnetic order persists up to room temperature due to the strengthened exchange interactions between Fe atoms via strongly polarized Pt near the Pt1-delta Fe delta/Co interfaces. For the Pt0.96Fe0.04/Pt multilayers, the magnetically ordered region in each Pt0.96Fe0.04 layer extends over at least 10 angstrom from the interface at room temperature. (C) 2010 Elsevier B.V. All rights reserved.