Write and Read Characteristics in Combination with a Single Pole Type Thin Film Head and a Double Layer Rigid Disk for Perpendicular Magnetic Recording

A single pole type thin film head for perpendicular magnetic recording was developed, and the effects of head and disk parameters were studied. The newly developed single pole head consists of an amorphous Co-Zr main pole and a coil of 16 turns. The pole is tapered at the tip end, ranging from 0.2 μm to 0.5 μm in thickness and from 2 μm to 15 μm in depth. First, the effects of the pole thickness and pole depth on write and read performance of the head were investigated. A CO-Cr/permalloy double layer rigid disk was used for evaluation. The thickness of the CO-Cr layer is 0.14 μm, and that of the permalloy underlayer is 0.5 μm. Perpendicular coercivity of the CO-Cr layer is 730 Oe. Recording density increased as the pole thickness decreased, and a D50 of 70 kFRPI was achieved for a head with a 0.2μm pole thickness. Isolated output was 0.53μVp-p/μm/turn at a disk speed of 6 m/s. Magneto-motive force for saturation recording was as low as 0.19 AT. It was found that the influence of the pole depth on the write and read performance is very little. Next, the effects of perpendicular coercivity and film thickness of the double layer disk on the recording characteristics were examined. Recording density and write sensitivity were improved as the thickness of the Co-Cr layer decreased. Output voltage increased with the perpendicular coercivity.