Independent readout from double recording layer MO using two wave length laser beams

To achieve higher S/N on multi layer recording media, the multi wavelength readout system has been proposed. In this paper, the practical feasibility for independent readout from MO media having a double recording layer is confirmed using two wavelength laser beams. The layer structure of the media is substrate/SiN/TbFeCo/SiN/TbFeCo/PtCo/SiN. It has two TbFeCo recording layers which can store binary data respectively. The wavelength dependence of the Kerr rotation angle is reported. Actual recording experiments have been carried out using 780 nm and 680 nm lasers. Although some interlayer crosstalk still remains, this reproducing method has the advantage of high S/N readout.