SOFT-ADJACENT-LAYER OPTIMIZATION FOR SELF-BIASED MR ELEMENTS WITH CURRENT SHUNT LAYERS

A soft adjacent layer (SAL) for a self-biased magnetoresistive (MR) element has been optimized experimentally by the aid of simple computer simulation. In the element, a Ti current shunt layer is placed between an NiFe MR layer and an amorphous CoZrMo SAL. The maximum sensitivity and the minimum nonlinearity are calculated under the condition that the product of the thickness and the saturation magnetization Ms for the SAL is 75% of that for the MR layer. MR elements have been prepared with various combinations of thickness and Ms for the SAL. The thickness of both the NiFe and Ti films was 40 nm. The MR response of an element with a 100-μm-long, 10-μm-wide stripe pattern has been measured. The best biasing condition was achieved with 50-nm thickness and 480 emu/cc Ms for the SAL. A 0.028/Oe sensitivity value was measured. No Barkhausen jump was observed in the MR response.