Patent ID: 6028824
Filing Date: 2000-02-22
Classification: G11B

Abstract:
A process of recording information on a magnetooptical recording medium comprising a first magnetic layer; and a second magnetic layer positioned opposite to the first magnetic layer in a plane parallel to that of the first magnetic layer and exchange-coupled to the first magnetic layer, the second magnetic layer having a higher Curie point and a lower coercive force at room temperature than those of the first magnetic layer; wherein the following relationships are satisfied: ##EQU10## wherein H.sub.1 and H.sub.2 are respectively coercive forces at room temperature of the first and second magnetic layers,M.sub.s is the saturation magnetization of the second magnetic layer,.sigma..sub.w is the magnetic wall energy between the first and second magnetic layers, andL.sub.1 and L.sub.2 are respectively thicknesses of the first and second magnetic layers,the process comprising the steps of:orienting the direction of magnetization of the second magnetic layer in a predetermined direction, while retaining the direction of magnetization of the first magnetic layer; andselectively effecting either a first type of recording by irradiating the medium with a light beam having a power sufficient to heat the medium close to the Curie point of the first magnetic layer or, thereby orienting the direction of magnetization of the first magnetic layer in a direction that is stable with respect to the direction of magnetization of the second magnetic layer while retaining the direction of magnetization of the second magnetic layer, or a second type of recording by irradiating the medium with a light beam having a power sufficient to heat the medium close to the Curie point of the second magnetic layer while applying a bias magnetic field, thereby inverting the direction of magnetization of the second magnetic layer and orienting the direction of magnetization of the first magnetic layer in a direction that is stable with respect to the direction of magnetization of the second magnetic layer, according to an information signal.