Gap length and sensor height effects on readback signals in shielded magnetoresistive sensors

Shielded magnetoresistive transducers, linearized by a combination of shunt biasing and soft adjacent layer biasing, were fabricated with a range of gap lengths and sensor heights. The signal amplitude increased with the terminal resistance, but it appeared to be independent of the total gap length. Placing the sensor asymmetrically between the shields did not introduce any obvious longitudinal distortion into the shape of the isolated pulse. The pulse amplitude asymmetry was sensitive to the sensor height, with the degree of this sensitivity affected by the lengths of the two gaps. A transmission line calculation shows how the amplitude asymmetry is affected by the placement of the sensor between the two shields. The spatial sensitivity across the track was affected by both the sensor height and the sense current, systematically changing its apparent magnetic position