MR Response Stability on Geometry for an Abutted Junction of the MR Element and Longitudinal Bias Layer

Abstract

Hysteresis and baseline shift are studied in soft-adjacent-layer-biased MR sensors with abutted quasi-permanent magnetic bias. The magnet consists of NiFe/NiMn exchange-coupling films, which apply longitudinal bias field to an MR sensor. Abutted bias-magnet structures with various taper angles fabricated, and the overlap lengths were measured as the length of the MR flat active region covered by the longitudinal bias films. The hysteresis measured from the transfer curve decreases with decreasing overlap length. The repeatable baseline shift in the readback signal was also improved by decreasing the overlap length in the MR sensor.