Antiferromagnetic interlayer exchange coupling across an amorphous metallic spacer layer

TL;DR

This paper reports the first observation of antiferromagnetic coupling across an amorphous metallic spacer layer, revealing biquadratic coupling and explaining it via RKKY interaction considering the amorphous structure.

Contribution

It demonstrates for the first time antiferromagnetic interlayer exchange coupling through an amorphous metallic spacer, supported by experimental and microscopic analysis.

Findings

First observation of antiferromagnetic coupling across amorphous spacer

Identification of biquadratic coupling at transition regions

Explanation of coupling via RKKY interaction considering amorphous structure

Abstract

By means of magneto-optical Kerr effect we observe for the first time antiferromagnetic coupling between ferromagnetic layers across an amorphous metallic spacer layer. Biquadratic coupling occurs at the transition from a ferromagnetically to an antiferromagnetically coupled region. Scanning tunneling microscopy images of all involved layers are used to extract thickness fluctuations and to verify the amorphous state of the spacer. The observed antiferromagnetic coupling behavior is explained by RKKY interaction taking into account the amorphous structure of the spacer material.