IrMn spin-valves for high density recording

Abstract

Simple IrMn spin-valves are investigated for use in high density recording head sensors. Top-IrMn spin-valves of the form NiFeCr(40 Å)/NiFe(32 Å)/CoFe(5)/Cu(25 Å)/CoFe(30 Å)/IrMn(80 Å)/Ta(50 Å) were deposited by magnetron sputtering. By tailoring the pinned layer composition at the CoFe/IrMn interface to Co60Fe40, the exchange bias can be increased above 400 Oe with a GMR amplitude of about 12%. Recording heads were fabricated with total gap thicknesses down to 900 Å, magnetic trackwidth down to 0.2 μm and stripe height down to 0.3 μm. The transfer curve characteristics are found to agree reasonably well with micromagnetic modeling. The model is then used to predict head sensitivity loss from the combination of insufficient exchange bias and short sensor stripe heights.