Magneto-optic recording/reproducing method and device and magneto-optic recording medium used for them

A magneto-optic recording/reproducing device comprising:

• light irradiation means for irradiating a magneto-optic recording medium with a light beam, said magneto-optic recording medium having a recording track where at least a vertically magnetized film is provided and structure bands provided on both sides of the recording track, said light beam having a diameter larger than the width of the recording track, and
• magnetic field applying means for applying a magnetic field in a predetermined direction to an area of said magneto-optic recording medium irradiated with said light beam,
• wherein in recording, magnetized domains are recorded by heating an area larger than the width of the recording track to a temperature exceeding the Curie temperature of the vertically magnetized film using said light beam from said light irradiation means, whereby said magnetized domains are recorded in accordance with the direction of the applied magnetic field, and in reproduction, the magnetization state of the magnetized domains is read out from only an area limited by the width of the recording track using the light beam from said light irradiation means;
• wherein the magnetized domains are recorded in such a manner that the direction of applying said magnetic field is changed in accordance with a signal to be recorded;
• and
• wherein the area of said magnetized domains limited by the width of said recording track is a feather shape having forked projections extending in the direction of scanning said light beam, and the length of said projections along said recording track is smaller than 1/2 of the width of said recording track.

A magneto-optic recording medium comprising:

• a substrate;
• two structure bands provided on the substrate, the two structure bands being separated from each other to define a recording track therebetween;
• and
• a vertically magnetized film provided on the substrate and the two structure bands such that the two structure bands are disposed between the substrate and the vertically magnetized film, the vertically magnetized film being continuous over virtually the entire substrate;
• wherein magnetic domains are recorded on the vertically magnetized film by radiating a light beam having a diameter larger than a width of the recording track through the substrate and applying an external magnetic field to the magneto-optic recording medium while controlling a direction of the external magnetic field such that the magnetic domains are recorded on the vertically magnetized film in accordance with the direction of the external magnetic field;
• wherein the two structure bands have a thermal conductivity sufficiently lower than a thermal conductivity of the vertically magnetized film such that the structure bands help prevent heat from the light beam radiated through the substrate from influencing the vertically magnetized film in areas of the magneto-optic recording medium other than the recording track such that the magnetic domains are recorded on the vertically magnetized film only within the width of the recording track;
• wherein the two structure bands protrude from a surface of the substrate, thereby causing the vertically magnetized film to have an uneven surface, and further comprising a layer disposed on the vertically magnetized film;
• and
• wherein the layer has a thermal conductivity sufficiently lower than the thermal conductivity of the vertically magnetized film such that the layer cooperates with the two structure bands to prevent heat from the light beam radiated through the substrate form influencing the vertically magnetized film in areas of the magneto-optic recording medium other than the recording track such that the magnetic domains are recorded on the vertically magnetized film only within the width of the recording track.