Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

ACS Appl Mater Interfaces. 2022 Mar 16;14(10):12766-12776. doi: 10.1021/acsami.1c22341. Epub 2022 Mar 7.

Abstract

Nowadays, a wide number of applications based on magnetic materials rely on the properties arising at the interface between different layers in complex heterostructures engineered at the nanoscale. In ferromagnetic/heavy metal multilayers, such as the [Co/Pt]N and [Co/Pd]N systems, the magnetic proximity effect was demonstrated to be asymmetric, thus inducing a magnetic moment on the Pt (Pd) layer that is typically higher at the top Co/Pt(Pd) interface. In this work, advanced spectroscopic and imaging techniques were combined with theoretical approaches to clarify the origin of this asymmetry both in Co/Pt trilayers and, for the first time, in multilayer systems that are more relevant for practical applications. The different magnetic moment induced at the Co/Pt interfaces was correlated to the microstructural features that are in turn affected by the growth processes that induce a different intermixing during the film deposition, thus influencing the interface magnetic profile.

Keywords: Co/Pt multilayers; density functional theory; interface magnetism; magnetic heterostructures; magnetic proximity effect; resonant X-ray reflectivity; transmission electron microscopy.