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MA: Fachverband Magnetismus

MA 9: Spincaloric Transport (jointly with TT)

MA 9.12: Talk

Monday, March 7, 2016, 18:00–18:15, H31

Spin wave scattering and localization effects due to defects in magnetic materials — •Martin Evers, Cord A. Müller, and Ulrich Nowak — University of Konstanz, 78457 Konstanz, Germany

From earlier studies of transport of particles and waves it is known that there are different transport regimes. E.g. in a perfect crystal transport will be ballistic, but one usually has to deal with some kind of imperfections that induce disorder in the system. As Anderson has shown in 1958 in case of phase coherent transport disorder can also lead to completely suppressed transport, known as Anderson localization [1]. For the case of spin waves this will lead to a vanishing magnon propagation length, even without any damping mechanism [2,3].

Within a classical spin model utilizing the Landau-Lifshitz-Gilbert equation we study coherent backscattering (CBS), which is a weak localization phenomena and therefore a precursor for Anderson localization, in 2D. Especially the influence of non-linearities, damping and the Dzyaloshinskii-Moriya interaction is investigated. We also find evidence for coherent forward scattering [4] of magnons in a quasi one-dimensional setting, providing a direct signal of Anderson localization and absence of thermalization.

[1] P. W. Anderson, Phys. Rev. 109, 1492 (1958)
U. Ritzmann et al., Phys. Rev. B 89, 024409 (2014)
M. Evers et al., Phys. Rev. B 92, 014411 (2015)
T. Micklitz et al., Phys. Rev. Lett. 112, 110602 (2014)