Topological Spin Textures in an Insulating van der Waals Ferromagnet.

Generation and control of topological spin textures constitutes one of the most exciting challenges of modern spintronics given their potential applications in information storage technologies. Of particular interest are magnetic insulators, which due to low damping, absence of Joule heating and reduced dissipation could provide energy-efficient spin-textures platform. Here we demonstrate that the interplay between sample thickness, external magnetic fields and optical excitations can generate a prolific paramount of spin textures, and their coexistence in insulating CrBr 3 van der Waals (vdW) ferromagnets. Using high-resolution magnetic force microscopy and large-scale micromagnetic simulation methods, we demonstrate the existence of a large region in T-B phase diagram where different stripe domains, skyrmion crystals and magnetic domains exist and can be intrinsically selected or transformed to each-other via a phase-switch mechanism. Lorentz transmission electron microscopy unveiled the mixed chirality of the magnetic textures which are of Bloch-type at given conditions but can be further manipulated into Néel-type or hybrid-type via thickness-engineering. The topological phase transformation between the different magnetic objects could be further inspected by standard photoluminescence optical probes resolved by circular polarization indicative of an existance of exciton-skyrmion coupling mechanism. Our findings identified vdW magnetic insulators as a promising framework of materials for the manipulation and generation of highly ordered skyrmion lattices relevant for device integration at the atomic level. This article is protected by copyright. All rights reserved.