Effect of RKKY and dipolar interaction on the nucleation of skyrmion in Pt/Co multilayer with Ir spacer

TL;DR

This study demonstrates how RKKY and dipolar interactions in a Pt/Co multilayer with an Ir spacer stabilize skyrmions, with experimental evidence showing controllable skyrmion size and density for spintronic applications.

Contribution

It introduces a novel multilayer structure that leverages RKKY and dipolar interactions to stabilize and control skyrmions, advancing spintronic device design.

Findings

Skyrmions nucleate in the engineered multilayer structure.

Increasing Co thickness enlarges and densifies skyrmions.

Finite topological Hall effect confirms chiral spin textures.

Abstract

Magnetic skyrmions, topologically protected spin textures, have emerged as promising candidates for next-generation spintronic applications. In this study, we investigate the stabilization of skyrmionic states in a uniquely engineered Pt/Co multilayer system with an Ir spacer, where both Ruderman Kittel Kasuya Yosida (RKKY) and dipolar interactions play a crucial role. The studied multilayer structure consists of a synthetic antiferromagnetic (SAF) configuration, where a single Ir layer facilitates strong antiferromagnetic coupling between two ferromagnetic regions: FM1 (top) and FM2 (bottom), each formed by repeated Co layers separated by Pt, enabling significant dipolar interactions. This FM1/Ir/FM2 configuration results in a distinctive skyrmionic hysteresis loop, driven by the interplay of dipolar and RKKY interactions. Magnetic force microscopy (MFM) imaging confirms the nucleation of isolated skyrmions, while magnetotransport measurements reveal a finite topological Hall effect (THE), indicating the chiral nature of these spin textures. Furthermore, we demonstrate that increasing the Co layer thickness leads to a reduction in magnetic anisotropy, which in turn results in the formation of relatively larger and denser skyrmions. Our findings establish a robust approach for stabilizing skyrmions through the combined effects of dipolar and RKKY interactions, offering new pathways for controlled skyrmion manipulation in spintronic devices.