Perpendicular magnetic media by anodic oxidation method and their recording characteristics

Abstract

Magnetic alumite films containing electrodeposited Ni, Co and Fe were successfully prepared by employing an additional new process in the conventional anodic oxidation method in order to obtain suitable perpendicular coersive force below 1000 Oe. By this new process, the diameter of the micropores in the oxide layer was widened above 400 Å. The recording characteristics of the 5.25 inch rigid disks were evaluated using a Mn-Zn ferrite ring head with a gap length of 0.5μm. A recording density D50 of 42 kBPI was obtained for the disk with a media thickness of 1.5μm and a coercivity of 950 Oe. The output voltage was 1.2μ Vpp / μm. turn at 20 kBPI. Higher recording density of D50 was expected for the disk with a media thickness below 1.5 μm. It was shown that the present medium exhibit higher potential for recording than a conventional plated medium at high recording density region.