Microstructure and magnetic properties of fcc-FePt/L10-FePt exchange-coupled composite films

Abstract

The fcc-FePt/L10-FePt exchange-coupled composite films were prepared on (100)-oriented single-crystal MgO substrates using dc magnetron sputtering. The effects of fcc-FePt layer thickness and annealing temperature on microstructure and magnetic properties of fcc-FePt/L10-FePt films have been investigated. The fcc-FePt/L10-FePt film with high (001) orientation, low coercivity field, and strong soft/hard magnetic exchange-coupled interaction is obtained with 4 nm fcc-FePt layer. After annealing, there are interdiffusion and coalescence between fcc-FePt and L10-FePt layers. With increasing annealing temperature, (001) orientation and perpendicular magnetic anisotropy of the annealed films decrease, and coercivities increase. The annealed films have a relatively small value of switching field distribution.