SPIN-VALVE READ HEADS WITH NIFE CO90FE10 LAYERS FOR 5 GBIT/IN(2) DENSITY RECORDING/

Successful use of a NiFe/Co90Fe10 bilayer as a soft magnetic free laye r in spin-valve films with a GMR enhanced structure comprised of NiFe/ Co90Fe10/Cu/Co90Fe10/FeMn is outlined. The GMR ratio of the Spin-valve film with Co90Fe10 is over 7% and the coercivity of the free NiFe/Co9 0Fe10 bilayers is less than 5 Oe. A merged inductive/spin-valve head w as fabricated with a read track-width of 1.3 mu m and a read gap-lengt h of 0.26 mu m using spin-valve film with a Ta(50 Angstrom)/NiFe(45 An gstrom)/Co90Fe10(30 Angstrom)/Cu((32)Angstrom)/Co90Fe10(22 Angstrom)/F eMn(100 Angstrom)/Ta(10 Angstrom) structure and 260 Angstrom thick dom ain control Co78Cr10Pt12 magnet layers. Its read/write performance was tested on a low noise CoCr17Pt5Ta4 thin film disk with an Mr . t of 0 .41 memu/cm(2) and a coercivity of 2500 Oe. There is no Barkhausen noi se in the readback waveform. The result of the microtrack sensitivity profiles reveals an effective read track-width of 0.8 mu m. A normaliz ed output for a track-width of 880 mu Vpp/mu m and D50 of 166 kFCl was obtained. Using a PRML channel, a bit error rate of less than 10(-8) was obtained without error correction at a data rate of 3.3 MB/s and a t a linear density of 217 kBPI on a thin film disk with an Mr . t of 0 .72 memu/cm(2). Thus, 5 Gbit/in(2) density recording with a linear den sity of 217 kBPI and a track density of 23 kTPI is possible.