Surface Magnetic Effects in an Alternating Superlattice

Abstract

We investigate the surface magnetism of the alternating superlattice with localized spin-1/2. Using the mean-field approximation method, we discuss not only the correlation between the critical value j0C of the exchange constant in the surface layer and interlayer exchange constants, but also the connection between j0C and the bulk exchange constant jA. The calculated results are in good agreement with the former theoretical calculations. Based on the solutions, we show the relations between the critical parameter c = JS/JA and the bulk exchange constants as well as the surface transition temperature. JS is the exchange constant in the first two surface layers. Comparing with the earlier theoretical works, our results show the effect of the surface modification more gradual.