Performance study and analysis of dual-element head on thin-film disk for gigabit-density recording

Abstract

Inductive-write and magnetoresistive-(MR)-read dual-element heads with very narrow tracks and gaps have been designed, fabricated, and tested on thin-film media of high coercivity and squareness. The results not only show excellent writeability at modest write currents but also the existence of a narrow region of optimum write current, limited by the onset of self-erasure by the write head at high write currents. This leads to significant degradations of overwrite, signal amplitude, trackwidth, linear resolution and disk-noise-induced peak-jitters. A peak-jitter approach is shown to be useful in characterizing many aspects of recording performance. A peak-jitter evaluation of signal-to-noise behavior reveals not only satisfactory overall performance but also the dominance of disk noise as well as a concentration of the disk noise at the track edges. Peak-jitter evaluations of offtrack and squeeze behavior clearly demonstrate the narrow-track capabilities of these recording heads for high areal density operation