Enhanced skyrmion stability due to exchange frustration.

Autor: von Malottki S; Institute of Theoretical Physics and Astrophysics, University of Kiel, 24098, Kiel, Germany., Dupé B; Institute of Theoretical Physics and Astrophysics, University of Kiel, 24098, Kiel, Germany.; Institute of Physics, University of Mainz, 55128, Mainz, Germany., Bessarab PF; School of Engineering and Natural Sciences - Science Institute, University of Iceland, 107, Reykjavik, Iceland.; University ITMO, St. Petersburg, 197101, Russia., Delin A; Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Electrum 229, SE-16440, Kista, Sweden.; Department of Physics and Astronomy, Materials Theory Division, Uppsala University, Box 516, SE-75120, Uppsala, Sweden., Heinze S; Institute of Theoretical Physics and Astrophysics, University of Kiel, 24098, Kiel, Germany. heinze@physik.uni-kiel.de.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2017 Sep 26; Vol. 7 (1), pp. 12299. Date of Electronic Publication: 2017 Sep 26.
DOI: 10.1038/s41598-017-12525-x
Abstrakt: Skyrmions are localized, topologically non-trivial spin structures which have raised high hopes for future spintronic applications. A key issue is skyrmion stability with respect to annihilation into the ferromagnetic state. Energy barriers for this collapse have been calculated taking only nearest neighbor exchange interactions into account. Here, we demonstrate that exchange frustration can greatly enhance skyrmion stability. We focus on the prototypical film system Pd/Fe/Ir(111) and use an atomistic spin model parametrized from first-principles calculations. We show that energy barriers and critical fields of skyrmion collapse as well as skyrmion lifetimes are drastically enhanced due to frustrated exchange and that antiskyrmions are metastable. In contrast an effective nearest-neighbor exchange model can only account for equilibrium properties of skyrmions such as their magnetic field dependent profile or the zero temperature phase diagram. Our work shows that frustration of long range exchange interactions - a typical feature in itinerant electron magnets - is a route towards enhanced skyrmion stability even in systems with a ferromagnetic ground state.
Databáze: MEDLINE
Externí odkaz:
Nepřihlášeným uživatelům se plný text nezobrazuje