Magnetic interlayer coupling between ferromagnetic SrRuO3 layers through a SrIrO3 spacer

Abstract

A key element to tailor the properties of magnetic multilayers is the coupling between the individual magnetic layers. In the 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 SrRuO3 layers separated by spacers of the strong spin–orbit coupling oxide SrIrO3. This combination of oxide layers is being discussed as a potential candidate system to host Néel 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 sample signal. Additionally, FORC investigations enabled us to determine whether the coupling between the magnetic layers is ferromagnetic or antiferromagnetic. The observed interlayer coupling strength was very weak for the heterostructure with a two monolayer (ML) thick SrIrO3 spacer, and no coupling was observed for spacers of 6 and 12 ML thickness. The decoupling of the magnetic SrRuO3 layers due to the SrIrO3 spacer is a disadvantage for the study of skyrmions in such multilayers and indicates that other oxides have to be identified for realizing strong magnetic coupling.