Magnetic Skyrmions: Fundamental Physics and Spintronic Applications

2021 ◽  
Vol 31 (6) ◽  
pp. 287-295
Author(s):  
Dae-Han Jung ◽  
Ki-Suk Lee
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Mahesh Ramakrishnan ◽  
Evan Constable ◽  
Andres Cano ◽  
Maxim Mostovoy ◽  
Jonathan S. White ◽  
...  

AbstractMagnetic ground states with peculiar spin textures, such as magnetic skyrmions and multifunctional domains are of enormous interest for the fundamental physics governing their origin as well as potential applications in emerging technologies. Of particular interest are multiferroics, where sophisticated interactions between electric and magnetic phenomena can be used to tailor several functionalities. We report the direct observation of a magnetic field induced long-wavelength spin spiral modulation in the chiral compound Ba$${}_{3}$$3TaFe$${}_{3}$$3Si$${}_{2}$$2O$${}_{14}$$14, which emerges out of a helical ground state, and is hallmarked by the onset of a unique chirality-dependent contribution to the bulk electric polarization. The periodicity of the field-induced modulation, several hundreds of nm depending on the field value, is comparable to the length scales of mesoscopic topological defects such as skyrmions, merons, and solitons. The phase transition and observed threshold behavior are consistent with a phenomenology based on the allowed Lifshitz invariants for the chiral symmetry of langasite, which intriguingly contain all the essential ingredients for the realization of topologically stable antiferromagnetic skyrmions. Our findings open up new directions to explore topological correlations of antiferromagnetic spintronic systems based on non-collinear magnetic systems with additional ferroic functionalities.


Author(s):  
Takaaki Dohi ◽  
Robert. M. Reeve ◽  
Mathias Kläui

In condensed matter physics, magnetic skyrmions, topologically stabilized magnetic solitons, have been discovered in various materials systems, which has intrigued the community in terms of not only fundamental physics but also with respect to engineering applications. In particular, skyrmions in thin films are easily manipulable by electrical means even at room temperature. Concomitantly, a variety of possible applications have been proposed and proof-of-concept devices have been demonstrated. Recently, the field of skyrmion-based electronics has been referred to as skyrmionics and this field has been rapidly growing and extended in multiple directions. This review provides recent progress for skyrmion research in thin film systems and we discuss promising new directions, which will further invigorate the field. Expected final online publication date for the Annual Review of Condensed Matter Physics, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


1984 ◽  
Vol 45 (C3) ◽  
pp. C3-279-C3-284 ◽  
Author(s):  
P. Ageron ◽  
W. Mampe

Author(s):  
Richard Healey

The metaphor that fundamental physics is concerned to say what the natural world is like at the deepest level may be cashed out in terms of entities, properties, or laws. The role of quantum field theories in the Standard Model of high-energy physics suggests that fundamental entities, properties, and laws are to be sought in these theories. But the contextual ontology proposed in Chapter 12 would support no unified compositional structure for the world; a quantum state assignment specifies no physical property distribution sufficient even to determine all physical facts; and quantum theory posits no fundamental laws of time evolution, whether deterministic or stochastic. Quantum theory has made a revolutionary contribution to fundamental physics because its principles have permitted tremendous unification of science through the successful application of models constructed in conformity to them: but these models do not say what the world is like at the deepest level.


Author(s):  
Stuart Glennan

This chapter offers an account of mechanistic production, which is contrasted with Salmon and Dowe’s theory of physical production. It provides a new analysis of the nature of events, and an account of how those events can form productive causal chains. This account identifies three distinct kinds of production: constitutive, precipitating, and chained. The chapter shows how the New Mechanist account addresses a number of standard problems for theories of causation, and for mechanistic theories in particular. These include how mechanistic production could be grounded in fundamental physics, how productive theories can explain causation by omission, prevention, and disconnection, how to explain causal relevance without appeal to counterfactuals, and how to understand the relation between production and constitution in inter-level causal claims. The chapter concludes by discussing how the New Mechanist approach to causation and constitution leads to a sensible account of the nature and limits of reduction and emergence.


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