The dependence of giant magnetoresistance in an Fe-Mo multilayer on the thickness of the Fe layers

The magnetoresistance in Fe-Mo multilayers increases with decreasing thickness of the Fe layers. By comparing magnetoresistance and magnetization results, evidence for interlayer coupling variation was found with decreasing Fe layer thickness. Moreover, the behaviour of discontinuous or granular layers was observed in a sample with ultrathin Fe layers. The specific field dependence of the magnetoresistance, which obeys a Langevin-like function, suggests that scattering from an assemblage of superparamagnetic spins could be responsible for the observed magnetoresistance behaviour.