Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 44: Surface Magnetism (jointly with O)

MA 44.12: Vortrag

Donnerstag, 14. März 2013, 18:15–18:30, H3

Nano-skyrmions lattices and magnetic phase diagram of Fe/Ir(111) — •Nikolai Kiselev, David Bauer, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Recently, a square lattice of skyrmions of nanoscale dimension has been experimentally identified by spin-polarized scanning tunneling microscopy combined with first-principle calculations [1] as the ground state of an hexagonal Fe monolayer on the Ir(111) substrate. Here, we present a detailed theoretical description of the magnetic phase diagram of Fe/Ir(111) obtained from Monte Carlo simulations in extended Heisenberg model employing parameters obtained from first-principles calculations. We give a comprehensive analysis of the ground state and field/temperature induced transitions and compare our results with experiment. We predict the existence of a new modulated state: an hexagonal lattice of skyrmions stabilized at high field and temperature. The transition between hexagonal and square skyrmion lattices is characterized by an extremely strong hysteretic effect and the abrupt change of the topological number. We discuss in details general aspects of the nano-skyrmions, in particular leading terms in the Hamiltonian, which are responsible for the stability of skyrmions in low dimensional magnetic systems.

[1] S. Heinze et al. Nature Phys. 7, 713 (2011).