A storage method, used in rewritable optical disk drives, that combines magnetic and optical recording techniques. The disk is coated with film that initially is uniformly magnetized. A laser beam is used to demagnetize a small spot on the film by heating it above a critical temperature (the Curie point or compensation point), and a local magnetic field determines the direction in which the spot is magnetized when it cools. To read the information, the disk is scanned by polarized light from a low-power laser. The plane of polarization of the light reflected from a magnetized surface is rotated according to the direction of the magnetic field — the Kerr effect. This rotation, though small, can be detected and the original binary signal can be reproduced. Despite high reliability and long life, which make M-O storage attractive for specialized uses, it has not been widely adopted.