Effect of base pressure on the structure and magnetic properties of FePt thin films

We have investigated the effect of base pressure of the sputtering chamber on the structure and magnetic properties of the FePt thin films. The A1-FePt thin films deposited at room temperature, at a low base pressure of 5.5×10−7 Torr was ordered to the L10 structure at a low annealing temperature of 200 °C and a highly ordered L10 phase was formed by annealing the film at 300 °C. On the other hand, for the A1-FePt thin films deposited at a higher base pressure of 5.5×10−5 Torr, the ordering to the L10 structure took place at a higher annealing temperature of 400 °C and a fully ordered L10 phase was obtained when the film was annealed at 600 °C. These observations suggest that the low base pressure of the sputtering chamber is effective to reduce the kinetic ordering temperature to a much lower annealing temperature of 200 °C.