NARROW TRACK DUAL MAGNETORESISTIVE HEADS FOR TAPE

An experimental investigation of a dual magnetoresistive head tested o n a Metrum tape test stand, is presented. The dual magnetoresistive (D MR) head has a trackwidth of 4 mu m and a gap length of 0.1 mu m. Meta l particle tape, with a M-r delta of 16 memu/cm(2) and a coercivity of 1.8 kOe, was used. A square wave was recorded with an FeAlN thin film inductive head, with a trackwidth of 33 mu m and a gap of 1.9 mu m. A shielded shunt biased MR head used in quarter inch cartridge drives ( QIC), with a trackwidth of 19 mu m and a shield to element gap of 0.25 mu m was used as a benchmark. The DMR head showed a larger signal to dc erased noise per unit trackwidth than the QIC MR head, at linear de nsities of 20 to 100 kfci. Isolated transitions and dibits with a bit spacing of 0.3 mu m were recorded for time domain measurements. The di bit response of the DMR head, characterized by a unipolar pulse with s mall side over/undershoots demonstrated the differential character of the DMR head. The QIC MR head PW50, measured directly from the isolate d transition response and indirectly from the dibit response, was 1.4 mu m. This large PW50 value was essentially write process limited, to first order independent of the read head gap length. (C) 1997 American Institute of Physics.