Interlayer coupling enhanced by the interface roughness

TL;DR

This paper explains how interface roughness can enhance interlayer exchange coupling in Fe/Cr/Fe trilayers by creating resonant states, and proposes a systematic method to optimize this effect.

Contribution

It introduces a new theoretical approach to quantify and optimize the impact of interface roughness on interlayer coupling in heterojunctions.

Findings

Interface roughness can significantly enhance exchange coupling.

Resonant states are facilitated by correlated interface topography.

The method predicts optimal interface conditions for maximum coupling.

Abstract

Previous experiment on Fe/Cr/Fe(001) trilayers reported a surprising observation that the interlayer exchange coupling could be enhanced drastically by the bombardment of irradiation even at low fluences. We propose that it is due to the resonant states in the spacer, made possible when the topography of both interfaces is correlated and exhibits prominent Fourier components. A systematic procedure is developed to handle the interface roughness and predict on how to optimize the interlayer coupling. This method can be extended to bridge the gap between theories and experiments in other heterojunctions.