SKM 2021 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Skyrmions II (joint session MA/KFM)
MA 17.1: Hauptvortrag
Freitag, 1. Oktober 2021, 10:00–10:30, H5
Emergent electromagnetic response of nanometer-sized spin textures — •Max Hirschberger1,2, Takashi Kurumaji2, and Leonie Spitz2 — 1Quantum-Phase Electronics Center, The University of Tokyo, Bunkyo-ku 113-8656, Tokyo, Japan — 2RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Saitama, Japan
Recently, we have worked to reduce the size of topological spin textures in bulk magnets towards the scale of several nanometers, exploiting new material platforms which are centrosymmetric and thus fundamentally different from previously explored non-centrosymmetric (chiral or polar) systems. Nanometer-sized skyrmions reported here are not stabilized by the Dzyaloshinskii-Moriya interaction, but rather by frustrated exchange or Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions. A wide array of experimental techniques in condensed matter was incorporated to establish the presence of skyrmion lattices in the new materials Gd2PdSi3 and Gd3Ru4Al12, with Heisenberg Gd3+ magnetic moments.
When a conduction electron moves through such a topological spin texture, it acquires a quantum mechanical phase (Berry phase), sometimes modeled by a (virtual) emergent magnetic field Bem acting on the electron. Nanometric skyrmions give rise to Bem of order 500 Tesla, and we have recently found quantitative evidence for this giant Bem using electrical Hall measurements and thermoelectric properties such as the topological Nernst effect. Ongoing work is focused on the control of magnetic interactions and electromagnetic responses via chemical composition tuning.