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 400°C, drastic changes are observed with respect to crystallinity, saturation magnetization, and perpendicular anisotropy. Then at an annealing temperature of 480°C, the film structure becomes homogeneous. Furthermore, the films made especially at a high substrate temperature of 220°C 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.