PURPOSE: To enable easy overwriting by applying a magnetic field in the opposite direction from a recording magnetic field and inverting the magnetic moment of a 1st magnetic layer only at a part where a magnetic wall is present between the 1st magnetic layer and a 2nd magnetic layer.
CONSTITUTION: A magnetic field Hi is applied to the medium to uniformize the magnetic moment of the 1st magnetic layer 2 to one direction. Then while the recording magnetic field Hw is applied in the same direction with the magnetic field, recording laser power is varied between binary levels corresponding to a recording signal, which is recorded. When '0' corresponds to a case wherein the direction of the magnetic moment of the layer 2 is opposite from the direction of the magnetic field Hw and '1' corresponds to a case wherein the direction is the same, a bit of '0' is irradiated with high-level laser light to raise the temperature of the magnetic layer to Tb and the magnetic wall is formed between the layers 2 and 3 since the temperature difference between the layers 2 and 3 is small and an exchange coupling force is small. There, a magnetic field Hx is applied in the opposite direction from the magnetic field Hw to invert the magnetic moment of the layer 2 only at the part where the magnetic wall is present between the layers 2 and 3. Consequently, the overwriting is performed.
TOKITA TOSHIAKI
TANAKA MOTOHARU
