A resistor network theory of the giant magnetoresistance in magnetic superlattices

An explanation of the giant magnetoresistance effect observed in some magnetic superlattices is given in terms of an equivalent network of resistors. The model leads to a simple analytic formula that relates the magnetoresistance to the spin-dependent electron mean-free paths and thickness of the magnetic and nonmagnetic layers in the superlattice. The formula is used to study the giant magnetoresistance of Co/Cu and Fe/Cr superlattices, and is also used to predict the most favorable values of parameters for a large magnetoresistance effect.