Suppression of crack formation in garnet film by using a compound glass underlayer

Garnet film made as a magneto-optical medium suffers from the problem of crack formation, caused by the high temperature of the garnet film fabrication process. We solved this problem by using a compound glass with a yield point lower than the garnet heat-treatment temperature as an underlayer. This successfully suppressed the formation of cracks in the heat-treated garnet film. As a result, we obtained a garnet film recording medium with excellent crystalline structure and high coercive force.