DQMP Seminar - Prof. Dr. Marc Janoschek, Paul Scherrer Institute & Physik-Institut, Universität Zürich

14.05.2024 13:00 – 14:30

Tales of Magnetic Topology as told by Neutron Scattering
Prof. Dr. Marc Janoschek
Paul Scherrer Institute & Physik-Institut, Universität Zürich

Magnetic skyrmions are nano-sized, topologically non-trivial magnetic textures. The low electrical current density required to set skyrmions in motion highlights their potential for future race-track memory, spintronics, and neuromorphic computing devices. This efficient motion of skyrmions is a result of their coupling to the conduction electrons via the spin-torque transfer effect. Here the topological charge carried by skyrmions acts as an fictious magnetic field and leads to a topological Hall effect. In this talk, I will first report on our recent extensive inelastic neutron scattering study, which demonstrates that magnons— bosonic quasiparticles—equally experience a topological Hall effect when travelling across a skyrmion lattice texture in MnSi. Our study reveals that the magnon spectrum shows emergent Landau levels that are characteristic of the virtual magnetic field used to account for the nontrivial topological winding of a skyrmion lattice. This provides evidence of a topological magnon band structure in reciprocal space, which is borne out of the nontrivial real-space topology of a magnetic order. Finally, I will also present a extensive neutron diffraction study on a novel candidate material for topological magnetic textures. Notably, our study shows the presence of three distinct skyrmion lattice phases with different symmetry that can be accessed by tuning the applied magnetic field. Our study suggests that one of these phases has unique potential for optimizing the motion of skyrmions.


Organisé par : Prof. von Rohr

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückeberg

entrée libre