Design, fabrication and testing of spin-valve read heads for high density recording

Abstract

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 /spl mu/m, a read gap of 0.25 /spl mu/m, and a MR sensor height of 1 /spl mu/m. The spin-valve sensor had a structure of 100 /spl Aring/ NiFe/25 /spl Aring/ Cu/22 /spl Aring/ Co/110 /spl Aring/ FeMn, and yielded a net spin-valve coefficient of /spl sim/3.5% at the completion of head processing. 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 /spl mu/m showed linear, non-saturated signal response on a media with an areal moment as high as 1.25 memu/cm/sup 2/, yielding reasonably symmetrical signals with peak-to-peak amplitudes ranging from /spl sim/750 /spl mu/V//spl mu/m to as high as /spl sim/1000 /spl mu/V//spl 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. >