DESIGN, FABRICATION AND TESTING OF SPIN-VALVE READ HEADS FOR HIGH-DENSITY RECORDING

Spin-valve sensors of the type NiFe/Cu/Co have been designed for optimal biasing behavior and successfully incorporated into a gigabit-type shielded read head configuration with a read trackwidth of 2 mu m, a read gap of 0.25 mu m, and a MR sensor height of 1 mu m. The spin-valve sensor had a structure of 100 Angstrom NiFe/25 Angstrom Cu/22 Angstrom Co/110 Angstrom FeMn, and yielded a net spin-valve coefficient of similar to 3.5% at the completion of head professing. Uniform field testing of the read heads after wafer fabrication and lapping showed quiet and stable spin-valve response with near optimal bias performance. Recording tests of the read heads at a head-disk clearance of 1.5 mu in showed linear, non-saturated signal response on a media with an areal moment as high as 1.25memu/cm(2), yielding reasonably symmetrical signals with peak-to-peak amplitudes ranging from similar to 750 mu V/mu m to as high as similar to 1000 mu V/mu m of read trackwidth. Linear density rolloffs and microtrack profiles have also been studied, and results showed behaviors closely agreeing with design targets for high density recording operations.