The temperature dependence of interlayer exchange coupling - spin waves vs. spacer effects

There are different mechanisms proposed to be responsible for the temperature dependence of the interlayer exchange coupling (IEC), namely a smearing out of the spacer or interface Fermi surface and excitations and interactions of spin waves. We propose a possibility to separate both effects by calculating the excitation spectrum of an extended Heisenberg model and connecting the results with ferromagnetic resonance (FMR) experiments. To solve the Heisenberg model we use an approximation that was shown to yield excellent results. In this paper the main idea of this procedure is explained and a detailed investigation of the spin wave contribution to the temperature dependence of FMR resonance frequencies and fields is carried out.