US 6,272,077 B1 · Magneto-optical recording medium having intermediate layer of in plane magnetization

Abstract

A magneto-optical memory medium according to the present invention comprises a reproducing layer, which has in-plane magnetization at room temperature and perpendicular magnetization when heated to above a predetermined temperature by a reproducing light beam; a recording layer, which is magnetostatically coupled to the reproducing layer; and an in-plane magnetized layer, provided adjacent to the recording layer, which has a Curie temperature at the above-mentioned predetermined temperature. In this medium, at temperatures below the predetermined temperature, signals recorded at high density in the recording layer are masked, and the above-mentioned magnetostatic coupling is suppressed, by magnetic masking by the in-plane magnetized layer. At temperatures above the predetermined temperature, however, within a domain forming part of the in-plane magnetized layer, the recording layer and the reproducing layer are magnetostatically coupled, and a recording bit of the recording layer is copied and expanded to a magnetic domain in the reproducing layer. Accordingly, with this medium, by reproducing from an expanded magnetic domain of the reproducing layer, even information from recording bits recorded at high density can be reproduced with high signal quality.

Claims12

Dependent claims

A magneto-optical memory medium comprising:

a recording layer having perpendicular magnetization, in which the direction of perpendicular magnetization records information;
a reproducing layer which has perpendicular magnetization at least within a signal reproducing domain;
and
a magnetic masking layer adapted to allow leakage of magnetic flux from said recording layer at or above a predetermined temperature, thus copying magnetization of said recording layer to said reproducing layer, and adapted to suppress leakage of magnetic flux from said recording layer to said reproducing layer at temperatures below the predetermined temperature;
wherein said magnetic masking layer is provided in a position between said recording layer and said reproducing layer, but in non-abutting relationship with said reproducing layer.

2 more elements

A method of reproducing a magneto-optical memory medium comprising:

providing a recording layer having perpendicular magnetization, in which the direction of perpendicular magnetization records information;
a reproducing layer which has perpendicular magnetization at least within a signal reproducing domain;
and a magnetic masking layer adapted to allow leakage of magnetic flux from said recording layer at or above a predetermined temperature, thus copying magnetization of said recording layer to said reproducing layer, and adapted to suppress leakage of magnetic flux from said recording layer to said reproducing layer at temperatures below the predetermined temperature;
said magnetic masking layer being provided in a position between said recording layer and said reproducing layer, but in non-abutting relationship with said reproducing layer, and;
projecting a light beam onto said magneto-optical memory medium so as to form in said magnetic masking layer a high-temperature domain having a temperature at or above the predetermined temperature and a low-temperature domain having a temperature below the predetermined temperature, and so as to form in said reproducing layer a signal reproducing domain to which magnetization of said recording layer is copied, wherein the high-temperature domain of said magnetic masking layer and the signal reproducing domain of said reproducing layer are formed such that the signal reproducing domain is larger than the high-temperature domain.

2 more elements

Dependencies are inferred from the claim text.

Magneto-optical recording medium having intermediate layer of in plane magnetization

Life of this patent

Magneto-optical recording medium having intermediate layer of in plane magnetization

Life of this patent

Abstract

Claims12