Magneto-optic recording method and magneto-optic recording/reproducing apparatus

A magneto-optic recording/reproducing apparatus for recording information on and reading information from a magneto-optic recording medium having at least a reproducing layer and a recording layer, comprising:

• a recording optical head means having a recording light beam for recording information on the magneto-optic recording medium in a region smaller than a spot of a reading light beam employed for reading;
• a reproducing optical head means having said reading light beam for reading information by magneto-optic effect by changing a state of magnetization of the reproducing layer and at the same time irradiating the recording medium with the light beam;
• and
• a wavelength of the recording light beam emitted by the recording optical head means being substantially smaller than a wavelength of the reading light beam emitted by the reading optical head means.

A method for magneto-optic recording/reproducing employing a magneto-optic recording medium having a laminate construction of a reproducing layer and a record hold layer which are coupled magnetically, comprising the steps of:

• applying an external initializing magnetic field to the magneto-optic recording medium to turn a direction of magnetization of the reproducing layer in a direction for initialization before reproducing a recorded magnetic information;
• heating the magneto-optic recording medium and at a same time applying a magnetic field to the magneto-optic recording medium to transfer the recorded magnetic information from the record hold layer to the reproducing layer;
• reading the magnetic information from the reproducing layer by photoelectromagnetic effect;
• and
• providing a wavelength of a recording light beam for recording information on the magneto-optic recording medium substantially smaller than a wavelength of a reading light beam for reading the recorded information from the reproducing layer of the magneto-optic recording medium.

A method of reproducing a signal recorded in a magnetic domain of a magneto-optic recording medium, comprising the steps of:

• providing the magnetic medium as a first magnetic film, a second magnetic film and a third magnetic film which are coupled magnetically at a room temperature T.sub.RT, respective Curie points T.sub.c1, T.sub.c2, and T.sub.c3 of the first, second and third magnetic films meeting conditions expressed by inequalities:
• T.sub.c2 >T.sub.RT, T.sub.c2 <T.sub.c1, and T.sub.c2 <T.sub.c3, a coercive force H.sub.c1 of the first magnetic film being relatively small at a temperature substantially equal to the Curie point T.sub.c2 of the second magnetic film, and a coercive force H.sub.c3 of the third magnetic film being substantially greater than a required magnetic field intensity in a temperature range between the room temperature T.sub.RT and a predetermined temperature T.sub.PB higher than the Curie point T.sub.c2 of the second magnetic film;
• heating the magneto-optic recording medium at the predetermined temperature T.sub.PB to cancel the magnetic coupling of the first and third magnetic films and, at a same time, applying a magnetic field to cancel the magnetic fields or stray magnetic fields created by the magneto-optic recording medium, and to change a size of a magnetic domain in the first magnetic film;
• and
• providing a wavelength of a recording light beam for recording signals on the magneto-optic recording medium substantially smaller than a wavelength of a reproducing light beam for reproducing the recording signals.

A method for magneto-optic reproduction employing a magneto-optic recording medium having a laminate construction comprised of a reproducing layer, an intermediate layer and a record hold layer which are coupled magnetically, comprising the steps of:

• applying an initializing magnetic field to the magneto-optic recording medium to turn a direction of magnetization of the reproducing layer in a direction for initialization after signals have been recorded in the record hold layer of the magneto-optic recording medium;
• irradiating the reproducing layer with a reading laser beam while a reproducing magnetic field is applied to the magneto-optic recording medium to heat an area of the reproducing layer corresponding to a spot of the laser beam in temperature distribution so as to form a first region in which a state of magnetization formed by the initialization is maintained, a second region to which a magnetic domain pattern of the record hold layer is transferred, and a third region in which the direction of magnetization is turned in a direction of the reproducing magnetic field, said three regions being formed in the area of the reproducing layer corresponding to the spot of the laser beam;
• reading a magnetic signal in the second region of the reproducing layer to which the magnetic domain pattern of the record hold layer is transferred by converting a magnetic signal into an optical signal by photoelectromagnetic effect;
• and
• providing a wavelength of a recording laser beam for recording signals on the magneto-optic recording medium substantially smaller than a wavelength of the reading laser beam.

A magneto-optic recording/reproducing apparatus for recording information on and reading information from a magneto-optic recording medium having at least a reproducing layer and a recording layer, comprising:

• a recording optical head means having a recording light beam for recording information on the magneto-optic recording medium;
• a reproducing optical head means having a reading light beam for reading information from the reproducing layer;
• and
• a wavelength of the recording light beam emitted by the recording optical head means being substantially smaller than a wavelength of the reading light beam emitted by the reading optical head means.