Dynamics Of Magnetic Skyrmionsproject Supported By The National Natural Science Foundation Of China Grant Nos 11074216 And 11274272 And The Fundamental Research Funds For The Central Universities Of China

Abstract: We review the recent progress on the magnetic skyrmions in chiral magnetic materials. The magnetic skyrmion is a topological spin configuration with localized spatial extent, which could be thought of as an emergent rigid particle, owing to its particular topological and chiral properties. Static skyrmionic configurations have been found in various materials with different transport and thermodynamic properties. The magnetic skyrmions respond to externally applied fields in a very unique way, and their coupling to other quasiparticles in solid-state systems gives rise to the emergent electrodynamics. Being not only theoretically important, the magnetic skyrmion is also very promising to be the information carrier in next generation spintronic devices.

Abstract: Controllable formation and manipulation of domain walls in one-dimensional (1D) nanostripes underpins a promising type of emergent spintronic device. Magnetic skyrmion is topologically stable whirlpool-like spin texture and is expected to replace familiar domain wall phenomena to build such devices, owing to its prominent features including small size, topological stability and the small critical current required to move it. It is thus essential to understand skyrmions' properties in such a nanostructured element. In this paper, we mainly give fundamental insight into this issue. Experimental achievements in the formation and stability of individual skyrmions in the nanostripe are outlined in detail.

Abstract : From the topology of a synthetic aurora map, we propose a mechanism for the magnetic anomalies on the southern martian hemisphere, i.e., impacts by asteroids when the dynamo is active. The quasi concentric circles of aurora suggest that there are two-to-three convectional cells for each impact. The whole synthetic aurora is induced by three major impacts of asteroids. The east-west lineation features of crust magnetizations are due to the east-west trending locations of three impacts. The alternatively changed sign of crust magnetization originates from the alternatively changed flow direction on the tops of adjacent convectional cells.