Direct observation of Neel-type skyrmions and domain walls in a ferrimagnetic DyCo3 thin film

Isolated magnetic skyrmions are stable, topologically protected spin textures that are at the forefront of research interests today due to their potential applications in information technology. A distinct class of skyrmion hosts are rare earth - transition metal (RE-TM) ferrimagnetic materials. To date, the nature and the control of basic traits of skyrmions in these materials are not fully understood. We show that for an archetypal ferrimagnetic material DyCo3 that exhibits a strong perpendicular anisotropy, the ferrimagnetic skyrmion size can be tuned by an external magnetic field. Moreover, by taking advantage of the high spatial resolution of scanning transmission X-ray microscopy (STXM) and utilizing a large x-ray magnetic linear dichroism (XMLD) contrast that occurs naturally at the RE resonant edges, we resolve the nature of the magnetic domain walls of ferrimagnetic skyrmions. We demonstrate that through this method one can easily discriminate between Bloch and Neel type domain walls for each individual skyrmion. For all isolated ferrimagnetic skyrmions, we observe that the domain walls are of Neel-type. This key information is corroborated with results of micromagnetic simulations and allows us to conclude on the nature of the Dzyaloshinskii-Moriya interaction (DMI) which concurs to the stabilisation of skyrmions in this ferrimagnetic system. Establishing that an intrinsic DMI occurs in RE-TM materials will also be beneficial towards a deeper understanding of chiral spin texture control in ferrimagnetic materials. Magnetic skyrmions are topological spin textures that have potential implications for spintronic devices but greater control over their stability and physical characteristics are first required. Here, the authors study the formation of skyrmions in ferrimagnetic thin films of DyCo3 and using a combination of X-ray measurements determine them to be of the Neel type.

Automated summary

In this study, the authors investigate the magnetic domain walls of ferrimagnetic skyrmions in DyCo3 using scanning transmission X-ray microscopy (STXM) and X-ray magnetic linear dichroism (XMLD). They find that the domain walls of ferrimagnetic skyrmions in this material are of the Neel type. Micromagnetic simulations support these findings and provide insights into the nature of the Dzyaloshinskii-Moriya interaction (DMI) in ferrimagnetic systems, contributing to our understanding of control over chiral spin texture in these materials.