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TT: Fachverband Tiefe Temperaturen
TT 34: Focus Session: Dynamical Probes for Topological Magnetism
TT 34.3: Invited Talk
Wednesday, March 20, 2024, 10:30–11:00, H 0104
Probing spin dynamics by Hall effect and emergent inductance — •Max Hirschberger1,2, Jan Masell2,3, and Rinsuke Yamada1 — 1Dept. of Applied Physics, Univ. Tokyo, Tokyo, Japan — 2RIKEN Center for Emergent Matter Science, Wako, Japan — 3Karlsruhe Institute of Technology, Karlsruhe, Germany
For helimagnetic textures, an ongoing interest is the investigation of spin dynamics driven by current, or generated by thermal fluctuations. We study thermally induced spin chirality using the Hall / Nernst effects [1,2], and aim to develop inductance measurements, that is the detection of a phase-shifted voltage in response to a current excitation, as a tool to probe the low-lying excitations of spirals and cycloids, supporting thermodynamic and neutron scattering techniques.
Nagaosa (2019) first proposed that current-induced spin tilting of a proper screw or cycloid texture in metallic helimagnets generates an emergent electric field eem that is time delayed with respect to the excitation current; namely, an inductive response. This eem can be understood as spin winding in a two-dimensional plane spanned by time and space axes [3]. We have studied eem in spiral magnets, such as Gd3Ru4Al12, and found a sizable response that is linear in frequency, but nonlinear in the excitation current [4,5].
[1] K. Kolincio, M. Hirschberger et al., PNAS 118 (2021) e2023588118
[2] K. Kolincio, M. Hirschberger et al., PRL 130 (2023) 136701
[3] N. Nagaosa, Jpn. J. Appl. Phys. 58 (2019) 120909
[4] T. Yokouchi, F. Kagawa, M. Hirschberger et al., Nature 586 (2020) 232
[5] R. Yamada, M. Hirschberger, et al., in preparation (2024)
Keywords: Helimagnet; Spin chirality; Spin fluctuation; Emergent electromagnetism; Emergent inductance