Regensburg 2025 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 3: Multiferroics and Magnetoelectric Coupling (joint session MA/KFM)
KFM 3.10: Talk
Monday, March 17, 2025, 12:00–12:15, H16
Higher-order Magnetizations of Non-centrosymmetric Antiferromagnets — •Michael Paulsen1, Silvia Knappe-Grüneberg1, Jens Voigt1, Allard Schnabel1, Rainer Körber1, Michael Fechner2, Ivan Ushakov3, and Dennis Meier3 — 1Physikalisch-Technische Bundesanstalt, Berlin, Germany — 2Max Planck Institute for the Structure and Dynamics of Matter, CFEL, Hamburg, Germany — 3NTNU Norwegian University of Science and Technology, Trondheim, Norway
Antiferromagnetic materials lack macroscopic magnetic dipole fields, due to their compensated magnetic spin texture. In his seminal work, Dzyaloshinskii predicted that higher-order magnetization contributions arise in non-centrosymmetric antiferromagnets, in particular quadrupolar magnetic field contributions, and first experimental data suggested the presence of such fields in the antiferromagnetic model system Cr2O3. Here, we present calculations and measurements gained at cryogenic and room temperature using Superconducting Quantum Interference Devices (SQUIDs) and Optically Pumped Magnetometers (OPMs) setups, respectively, in ultra-low magnetic field environments. The results demonstrate the existence of quadrupolar far-fields and characteristic signatures in different classes of antiferromagnets. Importantly, our SQUID-based approaches are universal and can be applied to a wide range of systems, establishing new methods for characterizing materials with ultra-small magnetic remanence in general.
Keywords: Antiferromagnet; Far-field; Quadrupole; SQUID; Remanence