Gd-Layer-Inserted MSR MO Disk without an External Magnetic Field for MSR readout

Abstract

Recently, many types of magnetically induced super-resolution (MSR) have been proposed for high-density recording on magneto-optical (MO) disks. Among them, double-mask rear-aperture detection (D-RAD) is the most promising, because of its high resolution and crosstalk advantage. However, D-RAD requires a high external magnetic field for MSR readout. I investigated the use of MSR without a readout magnetic field, and made Gd-layer-inserted RAD(Gd-RAD) MO disk. This disk does not need external magnetic field for MSR readout. In recording on a Gd-RAD MO disk with land/groove recording, a C/N of more than 45 dB was achieved for a mark length of 0.3 μm at a track pitch of 0.7 μm.