THERMOMAGNETIC RECORDING METHOD APPLYING A POWER MODULATED LASER BEAM ON A MAGNETICALLY COUPLED MULTI-LAYER STRUCTURE OF A PERPENDICULAR ANISOTROPY MAGNETIC FILM

摘要

A thermomagnetic recording method is disclosed using a thermomagnetic recording medium where first, second and third magnetic thin films (1-3) each formed of rare-earth and transition metals are sequentially superposed to form layers in a magnetically coupled manner. The recording is carried out by heating the thermomagnetic recording medium under a predetermined magnetic field perpendicular to the film plane thereof while selectively modulating, in accordance with data to be recorded, a first heating state at a first temperature T1 substantially above the Curie point Tc1 of the first magnetic thin film (1) and adequate to hold the sublattice magnetization of the transition metal of the second magnetic thin film in a predetermined direction, and a second heating state at a second temperature T2 substantially above the Curie point Tc1 and adequate to invert the sublattice magnetization of the transition metal of the second magnetic thin film (2) to the reverse of the predetermined direction. In a cooling step subsequent to the first and second heating states, maintaining the sublattice magnetization of the third magnetic thin film in a predetermined direction while orienting the sublattice magnetization of said second magnetic thin film to be directionally coincident with that of the third magnetic thin film at a temperature below the first temperature T1 without directionally inverting the sublattice magnetization of the first magnetic thin film (1).