Reduction of coercivity in FePt-FeRh bilayer films by heating

In FePt(10 nm)-FeRh(25 nm), a large reduction of coercive field in the FePt layer occurs at a temperature just above the antiferro-ferromagnetic transition temperature of FeRh, which is attributable to the existence of an exchange spring mechanism. FePt(10 nm)-FeRh(7.5 nm) film does not show coercivity reduction due to the magnetic transition because of a high nucleation field for magnetization twisting of FeRh layer. The coercive field of the FePt layer is largely enhanced by field annealing.