Dipolar interaction, surface anisotropy and alloying effect on magnetic properties of the superlattice Ni_1–xFe_x/Cu

Abstract

The magnetic properties of superlattices Ni 1-x Fe x /Cu are studied within the spin wave theory framework for 0 ≤ x ≤ 0.2 and x = 1. The excitation spectra and the magnetization are calculated using a Green's function method. The results show that for each wave vector value, there are N coupled planar modes for a superlattice with N planes. A competition between the effects of long-range dipolar interaction and surface anisotropy is shown. The exchange and magnetic stability are reinforced when x increases. A comparison between the calculated and the measured magnetization under magnetic applied field gives a satisfactory estimation of the exchange integral values.