The effect of multilayer structure on magnetic properties of FePt thin films

The Fe/Pt multilayer films with different structures were deposited by RF magnetron sputtering on glass substrates, and the L10-FePt films were obtained after the as-deposited samples were subjected to vacuum annealing at various temperatures. Results show that the Fe/Pt multilayer structure can effectively reduce the ordering temperature of FePt film, and the in-plane coercivity of [Fe (5.2 nm)/Pt (5.2 nm)]7 multilayers can reach 161.2 kA/m after annealed at 350 °C for 30 min. When Fe and Pt layer thickness is equal, the coercivity of the film is the largest. On the other hand, the different Fe-Pt crystalline phases such as Fe3Pt and FePt3 phases are formed after annealing when the thickness ratio of Fe/Pt deviates from 1 after annealing. When Fe and Pt have the same thickness, the thinner single layer gets the lower ordering temperature and the larger coercivity.