Emergence of zero-field non-synthetic single and interchanged antiferromagnetic skyrmions in thin films

TL;DR

This paper reports the discovery of zero-field antiferromagnetic skyrmions in thin Cr films, revealing their potential for spintronic applications due to their stability and unique properties compared to ferromagnetic skyrmions.

Contribution

It demonstrates the existence of intrinsic AFM skyrmions in non-synthetic thin films, a significant step forward in AFM spintronics research.

Findings

Identification of AFM skyrmions in Cr thin films on PdFe/Ir(111)

Observation of interpenetrating chains of AFM skyrmions

Coexistence with ferromagnetic skyrmions in the same material

Abstract

Antiferromagnetic (AFM) skyrmions are envisioned as ideal localized topological magnetic bits in future information technologies. In contrast to ferromagnetic (FM) skyrmions, they are immune to the skyrmion Hall effect, might offer potential terahertz dynamics while being insensitive to external magnetic fields and dipolar interactions. Although observed in synthetic AFM structures and as complex meronic textures in intrinsic AFM bulk materials, their realization in non-synthetic AFM films, of crucial importance in racetrack concepts, has been elusive. Here, we unveil their presence in a row-wise AFM Cr film deposited on PdFe bilayer grown on fcc Ir(111) surface. Using first principles, we demonstrate the emergence of single and strikingly interpenetrating chains of AFM skyrmions, which can co-exist with the rich inhomogeneous exchange field, including that of FM skyrmions, hosted by PdFe. Besides the identification of an ideal platform of materials for intrinsic AFM skyrmions, we anticipate the uncovered knotted solitons to be promising building blocks in AFM spintronics.