Corrosion-Resistant GMR Head for Over 1-TB Tape System

We have developed a corrosion-resistant giant magnetoresistance (GMR) head using a spin-valve (Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) film for an over 1-TB helical tape system. The magnetic properties of the corrosion-resistant GMR head were preserved during a Battelle Class II test for 20 days. The sense current shunting in the spacer layer of the spin-valve film (SV) was less for CuAu than for Cu due to the higher resistivity of CuAu. The interlayer-coupling field in the corrosion-resistant SV film was about 25% that in conventional SV films. Therefore, each layer of the corrosion-resistant SV film was designed so as to optimize the bias point. For stripe-heights in the range from 0.7 to 0.4 mum, the asymmetry of the head output was maintained at plusmn20%. The recording characteristics had a signal-to-noise ratio (SNR) of 19.5 dB with a 0.7 mum track width at a 254 kFCI linear density. Using this head, a tape system of over 1 TB per cassette is possible