Ion beam sputtered spin-valve films with improved giant magnetoresistance response

A large value of giant magnetoresistance Delta R/R=9% with an exchange fiel d H-ex = 350 Oe has been measured from simple NiFe/CoFe/Cu/CoFe/IrMn top sp in-valve films prepared by ion beam deposition (IBD) techniques. The exchan ge biasing was greatly enhanced when a synthetic pinned layer, CoFe/Ru/CoFe , is used in the spin-valve structures. Apparent exchange field values in e xcess of 2000 Oe and Delta R/R values above 8% have been obtained in synthe tic spin-valve films. These IBD spin-valve films show excellent thermal sta bility and they are suitable for the applications in high density magnetic recording heads. (C) 1999 American Institute of Physics. [S0021-8979(99)347 08-3].