Magnetic hysteresis in nanostructures with thermally-controlled RKKY coupling

TL;DR

This paper investigates how thermal control affects magnetic hysteresis in nanostructures by analyzing competing RKKY and direct exchange interactions, supported by experimental and theoretical insights into magnetization switching mechanisms.

Contribution

It provides a detailed analysis of temperature-induced changes in magnetic hysteresis related to RKKY coupling and local anisotropy in nanostructures, combining experimental results with theoretical modeling.

Findings

Temperature changes alter hysteresis due to competing exchange interactions.

Step-like magnetization loops are caused by local anisotropy of nano-crystallites.

Comparison of experiment and theory clarifies switching mechanisms involving RKKY and direct exchange.

Abstract

Mechanisms of the recently demonstrated ex-situ thermal control of the indirect exchange coupling in magnetic multilayer are discussed for different designs of the spacer layer. Temperature-induced changes in the hysteresis of magnetization are shown to be associated with different types of competing interlayer exchange interactions. Theoretical analysis indicates that the measured step-like shape and hysteresis of the magnetization loops is due to local in-plane magnetic anisotropy of nano-crystallites within the strongly ferromagnetic films. Comparison of the experiment and theory is used to contrast the mechanisms of the magnetization switching based on the competition of (i) indirect (RKKY) and direct (non-RKKY) interlayer exchange interactions as well as (ii) indirect ferromagnetic and indirect antiferromagnetic (both of RKKY type) interlayer exchange.