A Study of Thin-Film Media Noise

The possibility of decreasing signal recorded noise in metal thin film media by decreasing the magnetic coupling between crystal grains was studied, with the following results. 1) The reverse DC erase noise is strongly related to the signal recorded noise. 2) The reverse DC erase noise characteristics show a positive peak for metal thin film media, in which there is strong coupling between crystal grains. 3) On the other hand, there is a negative dip in the characteristics of particulate media, in which the coupling between magnetic particles is weak. A Co-Cr thin film medium and an isotropic anisotropy particulate medium were selected as a medium with a weaker magnetic coupling than a metal thin film medium, and a Co-¿ sputtered medium which shows a positive peak in the reverse DC erase noise characteristic, respectively. The reverse DC erase noise characteristics of these two media both show dips. As expected from the above results, the signal recorded noise in Co-Cr media decreases slightly, and that in an isotropic particulate medium also decreases, as the recording density increases. Thus we confirmed the possibility of decreasing the signal recorded noise by reducing the strength of the magnetic coupling.