Ab initio theory of the interlayer exchange coupling

TL;DR

This paper reviews ab initio methods for calculating interlayer exchange coupling in magnetic multilayers, incorporating non-ideal interfaces and temperature effects, with numerical results demonstrating the theoretical approach.

Contribution

It introduces a comprehensive ab initio framework for analyzing interlayer exchange coupling, including temperature dependence and interface randomness, using advanced Green function techniques.

Findings

Numerical results validate the theoretical approach.

Temperature dependence of IEC can be effectively studied.

Asymptotic behavior analyzed via stationary-phase method.

Abstract

Ab initio formulations of the interlayer exchange coupling (IEC) between two, in general non-collinearly aligned magnetic slabs embedded in a non-magnetic spacer are reviewed whereby both the spacer and the magnetic slabs as well as their interfaces may be either ideal or random. These formulations are based on the spin-polarized surface Green function technique within the tight-binding linear muffin-tin orbital method, the Lloyd formulation of the IEC, and the coherent potential approximation using the vertex-cancellation theorem. We also present an effective method for the study of the temperature dependence of the IEC. The periods, amplitudes, and phases are studied in terms of discrete Fourier transformations, the asymptotic behavior of the IEC is briefly discussed within the stationary-phase method. Numerical results illustrating the theory are presented.