Magnetization reversal process in Fe/FePt films

Abstract

A soft/hard Fe/FePt bilayer with perpendicular magnetization was prepared on a glass substrate. Controlling the Fe layer thickness allowed modification of the hysteresis loops from rigid magnet with perpendicular magnetization to exchange-spring like magnet with parallel magnetization due to the nanoscale soft/hard interface coupling. For rigid magnetic films, the magnetization was reversed at a single switching field and interpreted by the two-spin model. In an exchange-spring like film, the in-plane magnetization reversal process was in two-steps and resulted from domain wall nucleation and propagation from the Fe layer into the FePt layer. © 2010 American Institute of Physics.