Theory of freezing temperatures of metallic spin glass multilayers

Abstract

A mean field approach is used to calculate the freezing temperature T g in metallic spin glass multilayer systems. We calculate the dependence of T g ( W SG) on the thickness W SG of spin glass layers separated by metallic interlayers of thickness W il large enough that the spin glass layers are not coupled to one another. We also calculate the dependence of T g ( W il ) on W il for the case where W il is small enough to allow coupling between the spin glass layers. Theoretical results are in good agreement with experimental data. Finite-temperature effects, scattering of electrons by nonmagnetic impurities, and intrinsic sd scattering of electrons by the spins play important roles in establishing the trends exhibited by T g ( W SG) and T g ( W il ). A clear physical interpretation is given which explains the behaviours of T g ( W SG) and T g ( W il ) in experimental spin glass multilayers. We also predict how T g ( W SG) and T g ( W il ) will behave if the nonmagnetic impurity concentration is nonnegligible.