Design, fabrication, and wafer level testing of (NiFe/Cu)(xn) dual stripe GMR sensors

In this paper, a new head design, the dual stripe GMR (DS-GMR) is proposed. It consists of two self biased GMR sensors of thickness t, carrying opposite sense currents I, separated by on oxide layer with thickness g. Modeling of the head shows that outputs of 1 mV/mu m trackwidth, with a D-50 of 300 kfci and PW50 congruent to 0.1 mu m can be achieved, which make it suitable for very high density operation. In order to test this DS-GMR sensor, (NiFe/Cu)(xn) GMR multilayers were developed with MR=12% and sensitivity of 0.25%/Oe. DS-GMR sensors were fabricated and tested at wafer level with bottom and top GMR of 4 to 5% for 5 mu m trackwidths and a gap g=0.2 mu m.