Observation of compact ferrimagnetic skyrmions in DyCo$_3$ film

TL;DR

This paper reports the discovery of compact ferrimagnetic skyrmions in DyCo$_3$ films, identified through advanced imaging and transport techniques, advancing the understanding of skyrmions in ferrimagnetic materials for spintronics.

Contribution

First observation of ferrimagnetic skyrmions in amorphous DyCo$_3$ films, combining multiple experimental methods to characterize their properties.

Findings

Skyrmions with ~40 nm core radius observed in DyCo$_3$ films.

Skyrmions formed during magnetic domain nucleation and annihilation.

Topological Hall effect indicates skyrmion presence.

Abstract

Owing to the experimental discovery of magnetic skyrmions stabilized by the Dzyaloshinskii-Moriya and/or dipolar interactions in thin films, there is a recent upsurge of interest in magnetic skyrmions with antiferromagnetic spins in order to overcome the fundamental limitations inherent with skyrmions in ferromagnetic materials. Here, we report on the observation of compact ferrimagnetic skyrmions for the class of amorphous alloys consisting of 4f rare-earth and 3d transition-metal elements with perpendicular magnetic anisotropy, using a DyCo$_3$ film, that are identified by combining x-ray magnetic scattering, scanning transmission x-ray microscopy, and Hall transport technique. These skyrmions, with antiparallel aligned Dy and Co magnetic moments and a characteristic core radius of about 40~nm, are formed during the nucleation and annihilation of the magnetic maze-like domain pattern exhibiting a topological Hall effect contribution. Our findings provide a promising route for fundamental research in the field of ferrimagnetic/antiferromagnetic spintronics towards practical applications.