Angular variation of giant magnetoresistance for current perpendicular to the plane of the layers

We present a quantum-statistical theoretical model using the Kubo formalism to describe the current-perpendicular-to-the-plane magnetoresistance (CPP-MR) of multilayers. The model deals particularly with noncollinear configurations of the magnetizations in successive layers. We compare the results of this model with an experimental investigation of the angular variation of the CPP-MR of (NiFe/Ag) multilayers. We conclude that in noncollinear magnetic configurations, interference between spin up and spin down electron waves give a contribution to the CPP-MR effect, and that mainly s-like electrons contribute to the CPP-MR.