CR-MIGRATION IN CONITA/CR FILMS BY ANNEALING

The CoNiTa/Cr double layered films for longitudinal magnetic recording media have been prepared by using Facing Targets sputtering apparatus. Substrate heating and post annealing were performed in order to increase the coercive force Hc. While the as-deposited film at the substrate temperature TS of 400°C had He of 780 Oe, the films deposited at TS of room temperature, exposed to atmosphere and annealed at 400°C had He as high as 1700 Oe. It has found that the some amount of Cr atoms migrated from under layer to magnetic layer and the vicinity of film surface. Consequently, such a large increase of He seemed to be attributed to isolation of magnetic grains by Cr atoms in their boundaries. © 1990 IEEE