Non-collinear Exchange Coupling in Trilayer Magnetic Junction and its Connection to Fermi Surface Topology

TL;DR

This paper explores how the topology of the Fermi surface influences the type of exchange coupling in a trilayer magnetic junction with Rashba interaction, revealing the conditions favoring RKKY or spiral interactions.

Contribution

It demonstrates the critical role of Fermi surface topology in determining non-collinear exchange interactions in magnetic trilayers with Rashba coupling.

Findings

Fermi surface topology dictates whether RKKY or spiral interactions dominate.

Numerical results connect Fermi surface features to exchange coupling behavior.

Potential implications for experimental design and spintronic applications.

Abstract

We investigate the non-collinear exchange coupling across the trilayer magnetic junction composed of an intermediate layer with Rashba interaction and two sandwiching ferromagnetic ones. To compute the mediated exchange coupling, one needs to go beyond the single-particle argument and integrate over the contributions from the whole Fermi surface. Surprisingly, we find that the topology of the Fermi surface plays a crucial role in determining whether the oscillatory RKKY or the spiral interactions would dominate. At the end, we discuss the connection of our numerical results to experiments and potential applications.