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

摘要

ABSTRACT OF THE DISCLOSURE:A thermomagnetic recording method isdisclosed using a thermomagnetic recording medium wherefirst, second and third magnetic thin films each formedof rare-earth and transition metals are sequentiallysuperposed to form layers in a magnatically coupledmanner. The recording is carried out by heating thethermomagnetic recording medium under a predeterminedmagnetic field perpendicular to the film plane thereofwhile selectively modulating, in accordance with datato be recorded, a first heating state at a firsttemperature T1 substantially above the Curie point Tcl ofthe first magnetic thin film and adequate to hold thesublattice magnetization of the transition metal of thesecond magnetic thin film in a predetermined direction,and a second heating state at a second temperature T2substantially above the Curie point Tcl and adequateto invert the sublattice magnetization of the transitionmetal of the second magnetic thin film to the reverseof the predetermined direction. In a cooling stepsubsequent to the first and second heating states,maintaining the sublattice magnetization of the thirdmagnetic thin film in a predetermined direction whileorienting the sublattice magnetization of said secondmagnetic thin film to be directionally coincident withthat of the third magnetic thin film at a temperaturebelow the first temperature T1 without directionallyinverting the sublattice magnetization of the firstmagnetic thin film.