Double-Mask RAD Media Designed for Short Wavelength

Abstract

This paper discusses double-mask RAD media for short wavelength recording. NdGdFeCo is used as a readout layer instead of GdFeCo, which is currently used in 1.3-GB, 3.5-inch MSR disk media. The Kerr rotation of NdGdFeCo is larger than that of GdFeCo at 410 nm, and the ellipticity of NdGdFeCo is smaller, which is effective for decreasing the cross-talk. By optimizing the magnetic and optical properties of the NdGdFeCo readout layer, a CNR as high as 45 dB was obtained for a mark length of 0.31 μm when a readout magnetic field of 400 Oe was applied, using a 680 nm laser.