MR/inductive head for hard disk drive

A SAL (soft adjacent layer) bias piggy back type magnetoresistive (MR)/inductive head was examined. On measuring the transconducting characteristics of the tested MR/inductive head, the following conclusions were reached: (1) Absolute output of 600 μVp-p was obtained, when the read track width was 4.0 μm, the medium speed was 6.4 m/s and the flying height was 0.15 μm. Thus, the superiority of this head compared with an ordinary inductive head was confirmed. (2) Although the MR element did not have a center tap, it was found that with a second harmonic distortion of under -26 dBm the head was suited for practical use. (3) The error rate curve of a worst-case pattern had 40% phase margin of 1172 fc/mm data window at error rate 10^-12. These results mean it can be used practically. This head is suitable for small-diameter high-capacity hard disk drives with 136 track/mm and 212 kB/mm² areal density corresponding to 100 MB in a 2.5-inch disk or 40 MB in a 1.8-inch disk