Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 2: Focus Session: Defects and Interfaces in Multiferroics 1

KFM 2.3: Vortrag

Montag, 5. September 2022, 10:20–10:40, H5

Tuning multiferroic properties in hexagonal YMnO₃ by manipulation of the structural order — •M. Giraldo¹, H. Sim², A. Simonov¹, M. Lilienblum¹, A. Samir¹, E. Gradauskaite¹, Y. Heo¹, M. Rossell³, M. Trassin¹, J.-G. Park², Th. Lottermoser¹, and M. Fiebig¹ — ¹Department of Materials, ETH Zurich — ²Department of Physics and Astronomy, Seoul National University — ³Electron Microscopy Center, EMPA

We investigate the enhancement and suppression of the structural distortion (Q) in hexagonal YMnO₃ upon substituting Mn by Al and Ga. We demonstrate its consequences on the electric and magnetic long-range order. We deploy various techniques for a systematic investigation. We observe a progressive decrease in the structural order. This behaviour is caused by the chemical pressure induced by the ionic size of Al and Mn. On the level of the ferroelectric domains, the suppression of the structural order manifests in a progressive size decrease upon increased Al concentration. We do not observe a domain size variation upon Ga substitution. Our experiments suggest that, surprisingly, the progressive reduction on the structural distortion is not directly proportional to a decrease in ferroelectric polarization. On the magnetic level, we find a progressive decrease of the ordering temperatures. This is due to the direct perturbation of the magnetic sublattices formed by the Mn³⁺ moments and the progressive dilution of the magnetic long-range order. By tracing changes in the inherent properties of these systems, we aim to broaden the understanding for new routes in the manipulation of ferroic properties in these compounds.