The 2020 skyrmionics roadmap

Abstract

The notion of non-trivial topological winding in condensed matter systems represents a major area of present-day theoretical and experimental research. Magnetic materials offer a versatile platform that is particularly amenable for the exploration of topological spin solitons in real space such as skyrmions. First identified in non-centrosymmetric bulk materials, the rapidly growing zoology of materials systems hosting skyrmions and related topological spin solitons includes bulk compounds, surfaces, thin films, heterostructures, nano-wires and nano-dots. This underscores an exceptional potential for major breakthroughs ranging from fundamental questions to applications as driven by an interdisciplinary exchange of ideas between areas in magnetism which traditionally have been pursued rather independently. The skyrmionics roadmap provides a review of the present state of the art and the wide range of research directions and strategies currently under way. These are, for instance, motivated by the identification of the fundamental structural properties of skyrmions and related textures, processes of nucleation and annihilation in the presence of non-trivial topological winding, an exceptionally efficient coupling to spin currents generating spin transfer torques at tiny current densities, as well as the capability to purposedesign broad-band spin dynamic and logic devices. arXiv:2001.00026v3 [cond-mat.str-el]

Nonmagnetic impurities in skyrmion racetrack memory

“…However, theoretical calculations have shown that Sk can be captured by a non-magnetic impurity if the current density is sufficiently small [9]. At present, the problem of the interaction of Sk with impurities is considered very important in the context of the Sk-RM construction [10,11].…”

Geometrically Constrained Skyrmions

“…Chiral structures in FeGe have been observed experimentally, such as at 100 K [37], but recent studies have evidenced that in this material system, skyrmions can be stable also near room-temperature [10,44]. These developments suggest that, although thermal stability is a topic of central importance in skyrmion research [3], temperature limits do not represent a significant obstacle in the case of FeGe.…”

“…Magnetic skyrmions, predicted by theory almost 30 years ago, have advanced to a central topic of research [1][2][3] in nanoscale magnetism over the last decade following their experimental observation [4,5]. Their particular topological properties [6], which impart them high stability and particle-like behavior [7][8][9], combined with their room-temperature availability [10,11], reduced dimensions [12], and their unique dynamic properties [13], render these magnetic structures promising candidates for future spintronic applications [14].…”

Intrinsic DMI-free skyrmion formation and robust dynamic behaviors in magnetic hemispherical shells

“…Chiral spin textures such as chiral domain walls 1 , vortices 2 , and skyrmions 3 , 4 are considered to be promising building blocks for prospective memory and logic devices in the field of spintronics 5 – 10 . In particular, the magnetic skyrmion has been intensively studied owing not only to its novel fundamental static and dynamic properties 11 – 15 but also to its technological applications to information-storage and -processing devices 16 , 17 .…”