Regensburg 2025 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Non-Skyrmonic Magnetic Textures I

MA 33.1: Talk

Thursday, March 20, 2025, 09:30–09:45, H16

Anomalous quasielastic scattering in centrosymmetric helimagnets — N. D. Andriushin¹, J. Grumbach¹, A. A. Kulbakov¹, Y. V. Tymoshenko^2,1, Y. A. Onykiienko¹, R. Firouzmandi³, E. Cheng³, S. Granovsky¹, Y. Skourski⁴, J. Ollivier⁵, H. C. Walker⁶, V. Kocsis³, B. Büchner³, M. Doerr⁷, •D. S. Inosov¹, and D. C. Peets¹ — ¹IFMP, TU Dresden, Germany — ²JCNS, FZ Jülich, Germany — ³IFW Dresden, Germany — ⁴HZDR, Dresden, Germany — ⁵ILL, Grenoble, France — ⁶ISIS, RAL, Didcot, UK — ⁷MPI-FKF, Stuttgart, Germany

Centrosymmetric helimagnets which host spin helices or skyrmion-like topological spin structures comprise a distinct subclass of materials in which helical order is stabilized by bond frustration in contrast to the more common path of antisymmetric exchange interactions. Here we will present the spin-dynamical properties of the SrFeO₃ [1] and Sr₃Fe₂O₇ [2] perovskites. Inelastic neutron scattering reveals that with increasing temperature, high-energy magnons increasingly lose coherence, and the spin fluctuations become dominated by a distinct quasielastic component at low energies, concentrated at the ordering wave vectors. This quasielastic component likely originates from helical domain walls. We anticipate that this could be generic to all symmetric helimagnets in which the chiral symmetry is spontaneously broken by the magnetic order.

References:
[1] N. D. Andriushin et al., arXiv:2409.10214 (2024).
[2] N. D. Andriushin et al., npj Quant. Mater. 9, 84 (2024).

Keywords: centrosymmetric helimagnets; helical domain walls; bond frustration; inelastic neutron scattering; spin waves