Anti-parallel longitudinal patterned exchange biased dual stripe magnetoresistive (DSMR) sensor element and method for fabrication thereof

A method for forming a longitudinally magnetically biased dual stripe magnetoresistive (DSMR) sensor element comprising:

• providing a substrate;
• forming over the substrate a patterned first magnetoresistive (MR) layer;
• forming contacting a pair of opposite ends of the patterned first magnetoresistive (MR) layer a pair of patterned first longitudinal magnetic biasing layers which defines a first trackwidth of the patterned first magnetoresistive (MR) layer, the pair of patterned first longitudinal magnetic biasing layers being biased in a first longitudinal magnetic bias direction substantially parallel with an axis of the patterned first magnetoresistive (MR) layer which separates the pair of patterned first longitudinal magnetic biasing layers;
• forming separated from the patterned first magnetoresistive layer by a non-magnetic spacer layer a patterned second magnetoresistive layer;
• forming contacting a pair of opposite ends of the patterned second magnetoresistive (MR) layer a pair of patterned second longitudinal magnetic biasing layers which defines a second trackwidth of the patterned second magnetoresistive (MR) layer, the pair of patterned second longitudinal magnetic biasing layers being biased in a second longitudinal magnetic bias direction substantially anti-parallel with the first longitudinal magnetic bias direction, wherein:
• the pair of patterned first longitudinal magnetic biasing layers and the pair of patterned second longitudinal magnetic biasing layers are formed of a single longitudinal magnetic biasing magnetic material;
• and
• the pair of patterned second longitudinal magnetic biasing layers is biased employing a thermal annealing method employing a thermal annealing temperature, a thermal annealing exposure time and an extrinsic magnetic bias field strength such that the pair of patterned second longitudinal magnetic biasing layers is biased in the second longitudinal magnetic bias direction while the pair of patterned first longitudinal magnetic biasing layers is not substantially demagnetized from the first longitudinal magnetic bias direction.