The effect of thickness and annealing condition on the microstructure and magnetic properties of Fe/Pt multilayer thin films

[Fe(0.5 nm)/Pt(0.5 nm)]40, [Fe(1 nm)/Pt(1.5 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 multilayer were prepared by DC magnetron sputtering. By conventional furnace annealing (CA) at 270-600 °C for various time, all of the films still remained the disordered structure with the soft magnetic phase. By rapid thermal annealing (RTA) at 500 °C for various time, we obtained the [Fe(1 nm)/Pt(1.5 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 films with L12 ordered FePt3 phase which was almost ferromagnetic at room temperature. However, the [Fe(0.5 nm)/Pt(0.5 nm)]40 films was still disordered state even under RTA. Compared with CA, RTA exposed an outstanding effect on accelerating the phase transition when the film thickness is over [Fe(0.5 nm)/Pt(0.5 nm)]40.