Magneto-optical disk having cellularly divided regions with alternating directions of magnetization and method of initializing direction of magnetization of magneto-optical disk prior to recording of information

摘要

A magneto-optical disk is of a type in which magnetic record pits are formed by thermomagnetic recording on a magnetic member and the pits are read utilizing the photomagnetic effect. The disk has cellularly divided regions arranged along a track direction on both sides of an information track on which a signal pit string is formed. The divided regions have alternately changing directions of magnetization. The magneto-optical disk is magnetized such that a focused laser beam is irradiated on the disk and an alternating magnetic field is applied to a portion irradiated by the laser beam.