The effect of interfacial regions on the giant magnetoresistance in as-grown and annealed Fe/Cr MLFs

The influence of microstructure, in particular at the Fe/Cr interfaces on the giant magnetoresistance of both as-grown and annealed Fe/Cr multilayer films (MLFs) has been studied. The giant magnetoresistance varies with the spin-dependent resistivity, but the spin-independent resistivity was found to have a much greater effect on the magnitude of the giant magnetoresistance. A simple model was devised to determine the thickness t(mixed) of the interfacial region across which the composition changed from pure Fe to pure Cr. The morphology of the interfaces was found to have a large influence on the magnitude of the giant magnetoresistance, and for a very diffused interface i.e. a large t(mixed), the giant magnetoresistance effect was suppressed. The optimum annealing condition was at a temperature of 300 degrees C for 1 h, with changes in giant magnetoresistance being largely due to a decrease in the spin-independent resistivity upon annealing. (C) 1999 Elsevier Science B.V. All rights reserved.