Patent ID: 6421304
Filing Date: 2002-07-16
Classification: G11B

Abstract:
A data reproducing apparatus handling a magneto-optical recording medium which consists at least of a displacement layer, a switching layer and a memory layer formed in this order, said memory layer being composed of a perpendicular magnetizing film, said displacement layer being composed of another perpendicular magnetizing film whose magnetic wall reluctance is relatively smaller than that of said memory layer and whose magnetic wall displaceability is relatively greater than that of said memory layer, said switching layer being composed of a magnetic layer whose Curie temperature is lower than those of said displacement layer and said memory layer; said data reproducing apparatus comprising:a signal reproducing means for irradiating a light beam from the side of said displacement layer onto said magneto-optical recording medium while moving the light beam relatively to said medium, and displacing a magnetic wall which has a gradient on the magnetic recording medium in the direction of motion of the light beam spot and is formed in said displacement layer with a temperature distribution having a temperature region higher than the Curie temperature of at least said switching layer, thereby obtaining a reproduced signal which corresponds to the change on a polarization plane of the reflected light of said light beam; a magnetic wall displacement detection means for detecting generation of the magnetic wall displacement by the use of a differential signal of the reproduced signal obtained from said signal reproducing means, or by the use of a difference signal thereof in the time base direction; and a data detection means for detecting data by the use of the detection signal obtained from said magnetic wall displacement detection means.