Resistance and spin-direction memory loss at Nb/Cu interfaces

Abstract

A new method is described for measuring the loss of spin-direction memory (spin relaxation) in nonmagnetic materials and at nonmagnetic interfaces. The method involves inserting the material of interest into an exchange-biased spin valve and monitoring the associated reduction in the spin valve’s magnetoresistance measured with the current perpendicular to the planes. This technique is tested by investigating spin relaxation near Nb/Cu interfaces. A surprisingly large loss per interface is found, between 15% and 25% with larger values being associated with thicker Nb layers.