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PGI-1 Talk: Anastasiia Varentsova
Finding the path: Various transformations that a magnetic system can undergo and their relevance for thermal stability and optimal control
- begin
- 13 Nov 2019 11:30
- venue
- PGI lecture hall
ITMO Univ., St. Petersburg, Russia
Abstract:
Topological magnetic states such as skyrmions may become the basis for digital technologies of the future. Experimental data [1,2] demonstrates that nanoscale magnetic skyrmions are only stable at low temperature, but room temperature stability is required for future applications. Here it is demonstrated by means of transition state theory [3] and atomistic spin Hamiltonian that the stability of nanoscale skyrmions can be enhanced to the desired level by a concerted adjustment of material parameters preserving the skyrmion size [4]. It is problematic to reach energy barriers exceeding thermal energy by a factor of 40-50 at room temperature - a commonly used criterion for reliable information storage - with realistic material parameter values while keeping the skyrmion size at nanoscale. However, sub-10 nm skyrmions in ultrathin ferromagnetic films can indeed be stable on a timescale of years at ambient conditions thanks to remarkably low attempt frequency. Unusual behavior of the attempt frequency is explained in terms of magnon-skyrmion bound states.
Contact
Prof. Dr. Stefan Blügel
