Annealing effects on properties of bi-substituted garnet films with perpendicular anisotropy prepared by a sol-gel method

Bi-substituted garnet Elms with perpendicular anisotropy have been prepared by a sol-gel method. Annealing effects on magneto-optical properties and structures of the Elms are studied. The results indicate that the Kerr hysteresis loops of garnet films have good squareness at annealing temperatures above 650degreesC, the coercive force H. of these films increases from 1070 to 1570 Oe with the increasing temperature from 650degrees to 700degreesC. The Kerr rotation of the Elms was changed with the increasing annealing temperature, and there is a maximum value (0.82degrees) at 675degreesC. It was found that the structure of the Elms is a single phase of garnet without preferring orientation when the annealing temperature is about 650degreesC, but a new phase (Bi2Al4O9) can be formed when the annealing temperature reaches 675degreesC, another new phase (Bi2Fe4O9) appears when the annealing temperature is about 700degreesC.