Switching off the magnetic exchange coupling by quantum resonances

TL;DR

This paper investigates how quantum resonances influence magnetic exchange coupling in trilayer systems, providing new insights into controlling magnetic interactions through quantum states and explaining experimental observations.

Contribution

It offers a detailed analysis of quantum-well states' role in magnetic trilayers and introduces methods to tune or switch off exchange coupling via quantum resonances.

Findings

Quantum-well states significantly affect magnetic coupling.

Heuristic models explain experimental subtleties.

Tuning quantum states can control exchange interactions.

Abstract

We clarify the role of quantum-well states in magnetic trilayer systems from majority carrier in the ferromagnetic and all carriers in the antiferromagnetic configurations. In addition to numerical and analytic calculations, heuristic pictures are provided to explain effects of a capping layer and side-layer modulation in recent experiments. This immediately offers answers to two unexplained subtle findings in experiments and band-structure calculations, individually. Furthermore, it allows a more flexible tuning of or even turning off the interlayer exchange coupling.