Domain structures in magnetoresistive granular metals

Abstract

We have imaged the magnetic domain structure of several heterogeneous CoxAg1−x alloys by using scanning electron microscopy with polarization analysis. These images show that extended domain structures exist in both the as-deposited samples and in samples annealed at moderate temperatures. This suggests that a significant fraction of the cobalt in these materials does not contribute to the giant magnetoresistance. Only those samples annealed at 600 °C and containing less than 40% cobalt by volume show no domain structure.