High density recording with single pole head.

The feasibility of high bit density recording was investigated experimentally in a perpendicular magnetic recording system using a single pole head and a Co-Cr/Ni-Fe double layer medium. To improve the reproducing sensitivity and resolution, the following were adopted: (a) Use of a newly developed high-sensitive single pole head. (b) Use of a medium with a relatively thin (0.1 μm) Co-Cr layer and a thick (0.5μm) Ni-Fe underlayer. (c) Achievement of head-to-medium spacings less than 0.03μm. As a result, reproduced signals were detected up to 680 kFRPI. The recording bit length at the highest density was of the order of the Co-Cr column diameter of the medium. This result proves that the high density recording up to the intrinsic limit of the medium is possible because this method is free from recording demagnetization effects at high densities.