Magnonic spin currents: Localization, propagation, and accumulation

In this work, the propagation of spin waves is discussed from a theoretical and computational point of view. For wave objects phase coherent transport in combination with disorder can lead to a complete suppression of transport. This in wave physics ubiquitous phenomena is called Anderson localization (also strong localization) because in this regime a wave packet is localized in a region which it cannot leave. Typical here is the exponential decay of the packets amplitude in space which defines a localization length. Numerical investigations of one and two dimensional magnetic systems give insight into scattering properties of the systems. We show directly the existence of Anderson localization in 1D and weak localization, which is a precursor for Anderson localization, in 2D. Here still a diffusive motion of magnons is observable, but the phase coherence give rise to non-classical behaviour, where the most famous is coherent backscattering.