Thermal degradation of PtMn-pinned top spin valves

The microstructure and magnetic properties of PtMn-pinned top spin valves were studied at various annealing temperatures. Magnetic properties were observed to degrade with increasing temperature, with the exchange coupling H/sub 1/ showing the fastest variation. The degradation did not appear to coincide with structural changes or large-stale diffusion. It will be shown that the results are consistent with the grain boundary diffusion degradation mechanism.