Disclosing the nature of asymmetric interface magnetism in Co/Pt multilayers

TL;DR

This paper investigates the asymmetric magnetic proximity effect in Co/Pt multilayers, revealing how microstructural features and growth processes influence the induced magnetic moments at interfaces using advanced spectroscopic, imaging, and theoretical methods.

Contribution

It provides the first detailed analysis of asymmetry in multilayer systems, linking microstructure and growth-induced intermixing to magnetic interface properties.

Findings

Asymmetry in induced magnetic moments is linked to microstructural features.

Growth processes affect intermixing and magnetic profiles.

Advanced techniques clarify the origin of interface magnetism asymmetry.

Abstract

Nowadays a wide number of applications based on magnetic materials relies 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, which are in turn affected by the growth processes that induce a different intermixing during the film deposition, thus influencing the interface magnetic profile.