Thermal degradation of exchange biased films in spin-valves

As part of an investigation of the thermal stability of spin valve structures, ferromagnetic resonance (FMR) and SQUID magnetometry measurements were made on an exchange biased film, Cu/sub 50/Ni/sub 50/13.1/Cu 2.0/Co 2.1/Ni/sub 80/Fe/sub 20/2.7/Fe/sub 50/Mn/sub 50/9.2/Cu 2.4 nm, as a function of annealing temperature up to 550/spl deg/C. The measurements show an enhancement in the exchange bias surface energy for annealing temperatures above 250/spl deg/C accompanied by increased FMR linewidth and reduced g/sub eff/ which are attributed to increased inhomogeneity of the exchange anisotropy. At temperatures as low as 200/spl deg/C, annealing produces large increases in moment per unit area which are indicative of diffusion.