Discovery and characterization of a new type of domain wall in a row-wise antiferromagnet

Abstract

Antiferromagnets have recently moved into the focus of application-related research, with the perspective to use them in future spintronics devices. At the same time the experimental determination of the detailed spin texture remains challenging. Here we use spin-polarized scanning tunneling microscopy to investigate the spin structure of antiferromagnetic domain walls. Comparison with spin dynamics simulations allows the identification of a new type of domain wall, which is a superposition state of the adjacent domains. We determine the relevant magnetic interactions and derive analytical formulas. Our experiments show a pathway to control the number of domain walls by boundary effects, and demonstrate the possibility to change the position of domain walls by interaction with movable adsorbed atoms. The knowledge about the exact spin structure of the domain walls is crucial for an understanding and theoretical modelling of their properties regarding, for instance, dynamics, response in transport experiments, and manipulation.

Nano-scale collinear multi-Q states driven by higher-order interactions

“…Not only periodic nano-scale magnetic textures, but also local magnetic perturbations in otherwise collinear states can be governed by such higher-order terms 34 , 35 . In particular in the growing field of spintronics using antiferro- 36 and ferrimagnets 37 an impact on transport properties such as the anomalous Hall effect 38 , 39 or the anisotropic magnetoresistance is expected depending on the detailed spin configuration in domain walls 40 or other topological defects such as skyrmions. Significant higher-order interactions have been reported in a range of materials including transition-metal interfaces 7 , 28 , 41 , rare-earth compounds 26 as well as two-dimensional van der Waals magnets 35 , 42 – 44 , which are therefore all potential candidates for the new type of spontaneous magnetic order proposed in our work.…”

Anisotropic Dzyaloshinskii–Moriya Interaction and Topological Magnetism in Two-Dimensional Magnets Protected by P4̅m2 Crystal Symmetry

“…37 Notably, X-ray photoemission electron microscopy and spin-polarized scanning tunneling microscopy have been shown to unveil AFM spin configuration. 38,39 In a general perspective, anisotropic DMI-induced and AFM topological spin textures are highly promising for applications in advanced spintronic devices.…”

“…Anisotropic DMI favors the formation of topological magnetism, such as antiskyrmion, which is a distinct type of skyrmion besides Bloch and Néel type, whose Hall angle can be directly controlled by the orientation of drive current. − In AFM systems, magnetic moments of coupled sublattices cancel out, resulting in zero dipolar field and enhancing the stability of topological magnetism; at the same time, the topological charge of coupled sublattices also cancel out, resulting in zero skyrmion Hall angle and high mobility. , A very recent theoretical study shows that skyrmion Hall effects could not disappear for spin orbit torque-driven AFM skyrmion/skyrmionium, because the magnus force does not cancel the different skyrmion structure while the spin Hall angle still vanishes for spin transfer torque-driven motion . Notably, X-ray photoemission electron microscopy and spin-polarized scanning tunneling microscopy have been shown to unveil AFM spin configuration. , In a general perspective, anisotropic DMI-induced and AFM topological spin textures are highly promising for applications in advanced spintronic devices.…”

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

“…The ground state is collinear row-wise AFM (RW-AFM) within the Cr layer (see inset of Fig. 1c), a configuration hosted by a triangular lattice so far observed experimentally only in Mn/Re(0001) 55,56 .…”