Spin valve heads with a corrosion resistant MnRh exchange layer

Abstract

A new exchange material, Mn/sub 78/Rh/sub 22/, is described, requiring no post-deposition anneal to obtain the antiferromagnetic phase and leading to spin valve sensors with good corrosion resistance, thermal stability up to 225/spl deg/C, and good exchange coupling characteristics. Potentiodynamic polarization scans performed in a sodium sulfate electrolyte show that Mn/sub 78/Rh/sub 22/ films exhibit a good corrosion resistance, comparable to that of Ni/sub 81/Fe/sub 19/, Mn/sub 80/Ir/sub 20/, and Mn/sub 50/Ni/sub 50/ films but with higher corrosion potential. Spin valve structures prepared with this exchange material show an exchange coupling strength (J/sub ex/) of 0.19 erg/cm/sup 2/. The blocking temperature (T/sub B/) of the as-deposited spin valve coupon samples is 235/spl deg/C. Unshielded sensors with trackwidths W=4-6 /spl mu/m and height h=1-2 /spl mu/m were fabricated. The sensors show well-linearized magnetoresistance (MR) transfer curves, without hysteresis or Barkhausen noise and are thermally stable under consecutive 5 h anneals in vacuum up to 225/spl deg/C. A shielded tape head device was fabricated showing a maximum output of 1.8 mV/sub pp///spl mu/m, with potential for operating at linear densities near 100 kfci, at which a 580 /spl mu/V/sub pp///spl mu/m output is measured.