Magnonics in skyrmion-hosting chiral magnetic materials

Datum

13.07.2017

Zeit

11:00 - 12:00

Sprecher

PD Dr. Markus Garst

Zugehörigkeit

Institut für Theoretische Physik, TU Dresden

Sprache

en

Hauptthema

Materialien

Andere Themen

Materialien, Physik

Host

Grit Rötzer

Beschreibung

A magnetization that spatially varies within a plane can be characterized by a topological skyrmion number specifying how often the magnetization vector covers the unit sphere. Magnetic skyrmion textures with such a non-trivial winding number are endowed with additional functionality as they efficiently couple to magnon- and itinerant spin currents allowing for novel spintronic applications. Such textures arise, in particular, in chiral magnets where the Dzyaloshinskii-Moriya interaction favours a spatially modulated magnetization. We provide an overview of the properties of magnon excitations in such materials including its magnon band structure and its inherent non-reciprocity [1,2]. Due to their non-trivial topology, a single skyrmion acts like a source of flux density that leads to an emergent Lorentz force on the magnons. This gives rise to skew and rainbow scattering of spinwavescharacterized by an asymmetric and oscillating differential cross section [2,3]. As a consequence of the skew scattering, a finite density of skyrmions will generate a topological magnon Hall effect. In a skyrmion crystal, this is reflected in non-trivial Chern numbers of the magnon bands also implying the presence of magnon edge states. We also discuss the momentum-transfer between magnons and skyrmions which allows to induce a skyrmion motion with the help of propagating spinwaves.

Links

• Seminars at the IFW

Letztmalig verändert: 13.07.2017, 09:37:11