Influence of quantum effects on giant magnetoresistance for multilayer structures

A description of the nonlinear conductivity of mesoscopic systems is formulated and used to describe quantum effects in the giant magnetoresistance of multilayer structures, based on a subdynamics approach. Consideration of the nonlinear response makes it possible to discuss the influence of bias and temperature on giant magnetoresistance. Calculations show that for sandwich structures, the giant magnetoresistance increases when the bias increases, and decreases for negative bias. Compared with the influence of bias, the variation of giant magnetoresistance with temperature is small.