MODELING STUDY OF ISOLATED READ-BACK PULSES FROM KEEPERED LONGITUDINAL THIN-FILM MEDIA USING THE BOUNDARY-ELEMENT METHOD

The magnetic effects of a saturable, magnetic keeper layer on the peak amplitude and shape of isolated read-back pulses from longitudinal th in film media were modeled as 2-dimensional magnetostatic field intera ctions using the boundary element method. The model assumes a standard thin film head and ny height of a 50% slider, a saturable NiFe keeper , and a perfectly sharp recorded transition in high-capacity longitudi nal thin film media, Isolated pulses calculated from the model show th at the keeper increases the peak amplitude(55%), decreases the half-he ight pulse width(46%), introduces pulse shape asymmetry, and eliminate s undershoots from pole edges. The pulse shape is found to be very sen sitive to changes in both the head-bias current and the head-disk spac ing.