Static characteristics of soft-adjacent-layer self-biased magnetoresistive heads

The soft adjacent layer (SAL) biasing scheme for magnetoresistive (MR) sensors offers the potential, for high performance with ease of fabrication. However, magnetoresistance versus applied uniform field transfer characteristics of such sensors can exhibit complex, hysteretic behavior. We will show two causes from which these effects can arise: electrical shorting between MR and SAL elements, and misalignment between the easy axes of the MR and the SAL and the sense current direction. These problems can be diagnosed and distinguished by examination of the current dependence of the magnetoresistance vs. applied uniform field characteristic. The sensitivity to misalignment can be overcome with a small easy-axis field.