Dresden 2020 – wissenschaftliches Programm
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TT 25.1: Hauptvortrag
Dienstag, 17. März 2020, 09:30–10:00, POT 6
Emergent electromagnetic response of nanometer-sized spin textures — •Max Hirschberger — Department of Applied Physics, University of Tokyo, Bunkyo-ku 113-8656, Japan — RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
A wide array of experimental techniques in condensed matter, including resonant elastic x-ray scattering and real-space imaging using Lorentz transmission electron microscopy, were incorporated to establish the presence of nanometer-sized skyrmion lattices in the new centrosymmetric materials Gd2PdSi3 and Gd3Ru4Al12, with Heisenberg Gd3+ magnetic moments and competing interactions. When a conduction electron moves through a topological spin texture, it acquires a quantum mechanical phase (Berry phase) which can strongly modify the dynamical properties of the electron gas. The tiny topological spin textures (skyrmions) in Gd2PdSi3 and Gd3Ru4Al12 are expected to give rise to a giant emergent magnetic field Bem of order 500 Tesla. We have recently found quantitative evidence for Bem using electrical Hall measurements and thermoelectric properties such as the topological Nernst effect. Ongoing work is focused on the tuning of magnetic interactions in these materials via chemical substitution; moreover, we are employing element-specific resonant x-ray scattering techniques to study the coupling between local moments and conduction electrons in this new class of skyrmion host.