SPIN-VALVE SENSORS WITH DOMAIN CONTROL HARD MAGNET LAYERS

We have fabricated unshielded narrow-track NiFe/Cu/NiFe/FeMn spin-valv e sensors with a height of 2 mu m and a track-width of less than 2 mu m using CoCrPt hard magnets (4 pi Mr= 5500 G, Hc= 1000 Oe) as a domain control layer. Barkhausen noise was completely suppressed by a longit udinal biasing field from the CoCrPt layers. The bias state was improv ed by applying a strong ferromagnetic exchange coupling field of 30 Oe between the free and pinned NiFe layers through a 14 Angstrom-thick C u interlayer. We have also fabricated shielded CoCrPt magnet-biased sp in-valve read heads with a track-width of 1.7 mu m. The heads had no B arkhausen noise and very low crosstalk noise.