Regensburg 2022 – wissenschaftliches Programm

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PRV: Preisträgervorträge

PRV I

PRV I: Preisträgervortrag

Montag, 5. September 2022, 13:15–13:45, H1

Ultrafast topological switching of magnetic skyrmions — •Felix Büttner — Helmholtz-Zentrum Berlin, Berlin, Germany — Laureate of the Walter-Schottky-Prize 2022

Magnetic skyrmions are non-collinear arrangements of spins, characterized by a defining non-trivial topology and a quasi-particle character. Skyrmions can be of nanometer-scale size, even at room temperature and - upon suitable stimulation - they can move coherently within their hosting material. Both, the stability and the emergent quasi-particle dynamics of skyrmions, can be linked to their topology, and these exotic properties have widely inspired research in fundamental and applied physics alike. In this talk, I will first give an overview of the field of skyrmionics before discussing one particularly fascinating aspect in greater depth: the possibility to switch, i.e., nucleate or annihilate, magnetic skyrmions despite their topological protection. I will show that the topological nucleation energy barrier of skyrmions, which can be understood from a simple product of magnetic exchange energy and film thickness, can surprisingly be lifted by heating the system into a newly discovered fluctuation state. This allows the simultaneous nucleation of an extended array of skyrmions, even on a picosecond time scale, as we could evidence by direct experimental observation. I will discuss this mechanism in the context of topological phase transitions and conclude with a perspective on technological applications.