Magnetic interlayer coupling between ferromagnetic SrRuO$_3$ layers through a SrIrO$_3$ spacer

TL;DR

This study investigates the magnetic interlayer coupling in epitaxial oxide heterostructures of SrRuO$_3$ separated by SrIrO$_3$, revealing weak coupling that varies with spacer thickness, relevant for skyrmion hosting applications.

Contribution

It demonstrates the use of FORC measurements to analyze magnetic coupling and distinguishes between ferromagnetic and antiferromagnetic interactions in oxide multilayers.

Findings

Weak interlayer coupling observed across all spacer thicknesses

FORC measurements effectively differentiate magnetic switching processes

Coupling strength varies with spacer thickness from 2 to 12 monolayers

Abstract

A key element to tailor the properties of magnetic multilayers is the coupling between the individual magnetic layers. In case of skyrmion hosting multilayers, coupling of skyrmions across the magnetic layers is highly desirable. Here the magnetic interlayer coupling was studied in epitaxial all-oxide heterostructures of ferromagnetic perovskite SrRuO$_3$ layers separated by spacers of the strong spin-orbit coupling oxide SrIrO$_3$. This combination of oxide layers is being discussed as a potential candidate system to host N\'{e}el skyrmions. First order reversal curve (FORC) measurements were performed in order to distinguish between magnetic switching processes of the individual layers and to disentangle the signal of soft magnetic impurities from the samples$'$ signal. Additionally, FORC investigations enabled to determine whether the coupling between the magnetic layers is ferromagnetic or antiferromagnetic. The observed interlayer coupling strength was weak for all the heterostructures, with SrIrO$_3$ spacers between 2 monolayers and 12 monolayers thick.