ANNEALING OF SPIN VALVES WITH HIGH EXCHANGE PINNING FIELDS

Practical spin valves for ultra-high density recording heads require p inning fields in excess of 250 Oe to resist demagnetizing effects. One approach to achieving such high fields is through extremely thin pinn ed layers. Unfortunately, the thin layers of magnetic material are sus ceptible to annealing effects arising from the moderate temperatures a t which spin valves are processed into heads. This is evidenced by a d rift in pinning field, By subjecting spin valves to a short term, high temperature anneal before prolonged storage at 60 degrees C, subseque nt drift in pinning field is suppressed.