Effects of heat treatment conditions and impurity doping on garnet films for M-O recording prepared by pyrolysis

The heat-treatment conditions of Bi-doped iron garnet films for magnetooptical recording prepared by pyrolysis onto glass substrates were studied. The effects of impurities such as Li, Na, Rb, and Cs were also studied. A low annealing temperature for crystallization and a low drying temperature were found to be effective in improving the morphology of the films. Doping with Na, Rb, and Cs were effective for obtaining films having improved morphology. It made coercivity lower and also made the Faraday hysteresis loop square compared with nondoped films. The rate of crystallization of the films doped with these impurities (except Li) was made much higher than for nondoped films