Magnetic properties and microstructure of Fe∕Pt multilayer films capped with SiO2 amorphous layer for magnetic recording use

Abstract

Fe ∕ Pt multilayer films capped with an amorphous SiO2 layer have been fabricated in order to study the microstructure and magnetic properties via a molecular beam epitaxy technique at 400°C. The formation of granularlike FePt films was obtained with this process due to the interpenetration of SiO2 which has a lower surface energy. Studies of angular dependent coercivity show a tendency of a domain-wall motion weaken toward rotation of reverse-domain type upon thickness of SiO2 capping layer atop the Fe∕Pt multilayer films. The intergrain interaction was confirmed from the Kelly–Henkel plot that indicated the exchange coupling between neighboring grains in the uncapped FePt films. On the other hand, negative δM value was obtained when the FePt films capped with SiO2 layer, indicating that the SiO2 capping layer can lead to the reduction of intergrain exchange coupling in SiO2/FePt films.