Structural and magnetic properties of a core-shell type L10 FePt/Fe exchange coupled nanocomposite with tilted easy axis

Structural and magnetic properties of core-shell type L1(0) FePt/Fe exchange coupled nanocomposites are studied systematically. Core-shell nanocomposites with FePt core and Fe shell are obtained by depositing Fe cap layers on granular L1(0) FePt films. Epitaxial growth is disclosed by x-ray diffraction. Coercivity decreases drastically for FePt/Fe with the thickness increase of Fe cap layers. The coercivity reduction is due to the much increased domain wall area pinned and compressed at the soft-hard interface, and the tilted effective easy axis because of the presence of demagnetized energy. L1(0) FePt/Fe with a 3 nm Fe layer has high thermal stability and gain factor for media applications. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3569845]