MODELING AND MEASUREMENT OF HARD-MAGNET BIASING STRENGTHS ON MR-SAL STRUCTURES

MR sensors using a SAL for transverse biasing, and patterned hard-magn ets for longitudinal biasing have been fabricated and tested. The perm anent magnet biasing fields of these MR-SAL structures are investigate d both theoretically and experimentally. Increasing the external longi tudinal offset field along the permanent magnet biasing direction stab ilizes the transverse response and reduces the device sensitivity; inc reasing this field along the opposite direction causes magnetic hyster esis. The threshold offset field at the onset of Barkhausen noise meas ures the average permanent-magnet longitudinal biasing strength. Good correlations with other test methods and micromagnetic simulations are obtained.