Effects of annealing condition on the structural and magnetic properties of FePt thin films

Equiatomic FePt films were deposited by a dc sputtering method and annealed in the air and in a vacuum at 350/spl deg/C for up to 60 min. The order-disorder transformation occurs almost entirely within 10 min and a very high coercivity of 6.8 kOe could be obtained in the air-annealed films while the transformation occured very slowly in the vacuum-annealed films. This higher transformation rate could be also verified in the X-ray diffraction analysis. The reason for the higher rate seems to be the diffusion of oxygen atoms and possible mechanism was discussed.