Annealing effect on sputtered CoCr films

Changes in structure of sputter-deposited CoCr films are discussed in conjunction with those in magnetic properties by means of annealing. At an annealing temperature of 400degC, drastic changes are observed with respect to crystallinity, saturation magnetization, and perpendicular anisotropy. Then at an annealing temperature of 480degC, the film structure becomes homogeneous. Furthermore, the films made especially at a high substrate temperature of 220degC are suggested to be composed of at least two regions with different lattice coherency along the film thickness; such a structure contributes to a large value of the perpendicular coercivity and, together with segregation, to the perpendicular anisotropy. (author)