EFFECT OF SENSE CURRENT ON BARKHAUSEN NOISE IN MAGNETORESISTIVE RECORDING-HEADS

The currents in the contact leads of a magnetoresistive (MR) head produce fields that influence the behavior of the underlying MR element. In the conventional lead configuration the current enters and leaves the MR element on the same side of the MR element. In the region where the conductor overlaps the MR element a field is produced that has a component that is along the easy axis of the MR element. The direction of this longitudinal field is in opposite directions on either side of the track and this destabilizes the MR element. Barkhausen noise results from the multidomain states that are produced. If instead the leads are configured to be on either side of the element the longitudinal fields are in the same direction and a single-domain state is stabilized. Results are presented that demonstrate the dependence of the hysteresis on the current. Kerr microscope measurements are shown that illustrate the behavior of the magnetization in the elements.