抄録
Co-γ-Fe2O3 perpendicular magnetic recording thin-film disks were prepared by annealing a CoO-Fe3O4 single layer deposited on an NiO underlayer in air, at temperatures ranging from 260°C to 350°C. The disks had no protective overcoat layers. The noise characteristics of Co-γ-Fe2O3 disks were measured by using a MIG-type ring head with a gap length of about 0.2μm in contact sliding use. By measurement of the dc erase noise spectrum and the recording density dependence of the medium noise, it was found that the disks show noise characteristics which is often seen in thin film media. At high recording densities of over 40 kFRPI, the disks show a higher Sp-p/Nm,rms than various longitudinal recording media now on the market.