Dresden 2020 – scientific programme

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MA: Fachverband Magnetismus

MA 21: Ultrafast Magnetization II

MA 21.14: Talk

Tuesday, March 17, 2020, 13:00–13:15, HSZ 101

Ultrafast magnetization switching in a model system of alloys with exchange coupling - a parameter study — •Kai Leckron and Hans Christian Schneider — University of Kaiserslautern, Department of Physics

Optically induced deterministic switching was demonstrated in GdFeCo with antiferromagnetic coupling between the sublattices [1] and theoretically related to thermal effects [2,3].

We study antiferromagnetically coupled-sublattice dynamics in a model consisting of two subsystems with itinerant and localized single-particle states [4]. After an instantaneous excitation of the itinerant subsystem we dynamically calculate the carrier dynamics in both subsystems using Boltzmann scattering integrals for exchange scattering processes. In agreement with Ref. [4], we find that on ultrashort time scales (some 10 fs) exchange dominates over Elliott-Yafet like spin-flip scattering.

We identify parameter regions where the so called "transient ferromagnetic state" appears and others where even a revearsal of the magnetization occurs. We also find a connection between the existence of a compensation temperature in the equilibrium magnetization curve and the magnetization switching, which is in agreement with recent atomistic simulations [5].

[1] Radu et al., Nature 472, 205 (2011) [2] J. H. Mentink et al., Phys. Rev. Lett. 108, 057202 (2012) [3] T. A. Ostler, Nat. Commun. 3, 666 (2012) [4] A. Baral and H. C. Schneider, Phys. Rev. B 91, 100402(R) (2015) [5] Moreno et al., Phys. Rev. B 99, 184401 (2019)