Write ard 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. Poles are tapered at the tip end, and range from 0.2 to 0.5 micron in thickness and from 2 to 15 microns 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 micron, and that of the permalloy packing layer is 0.5 micron. Perpendicular coercivity of the Co-Cr layer is 730 Oe. The recording density increased as the pole thickness decreased, and a D
₅₀
of 70 kFRPI was achieved for a head with a 0.2-micron pole thickness. Isolated output was 0.53 μVp-p/micron/ turn at a disk speed of 6 m/s. The magnetomotive force required for saturation recording was as low as 0.19 AT. It was found that there is very little influence of the pole depth on the write and read performance. The effects of perpendicular coercivity and film thickness of the double layer disk on the recording characteristics were examined. The recording density and write sensitivity were improved as the thickness of the Co-Cr layer decreased. The output voltage increased with the perpendicular coercivity.