Improvement of readout resolution with an in-plane magnetization film for a magneto-optical disk

For high density recording of magneto-optical disks, we have developed a new method that improves the apparent optical resolution using a medium that consists of a GdFeCo readout layer and a DyFeCo recording layer. The magnetization of the readout layer is designed to be in-plane at room temperature and to become perpendicularly oriented at high temperatures. Therefore, this medium shows polar Kerr effect only at areas heated up by a readout beam whereas the other areas of the medium are masked by an in-plane magnetization. Using this medium, a small bit at the center of the readout beam spot can be detected without cross talk from the neighborhood. The function of the above high resolution readout method was calculated and confirmed through the study of magneto-optical properties