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 2.2: Vortrag

Montag, 5. September 2022, 10:00–10:20, H5

Engineering of improper ferroelectric vortex- and stripe-like domains in polycrystalline ErMnO₃ — •Max Haas, Jan Schultheiß, and Dennis Meier — Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway

The functionality and physical properties of ferroelectric materials are intimately coupled to their domain structure. An exciting recent discovery are topologically protected vortex domains in hexagonal manganites, which are of interest for different fields ranging from nanoelectronics to cosmology-related questions. A key characteristic of the domain structure is the vortex density, that can readily be tuned via the cooling rate across the ferroelectric phase transition.
Here, we explore the effect of cooling rate variations in combination with three-dimensional spatial confinement in high-quality ErMnO₃ polycrystals. Utilizing piezoresponse force microscopy, we demonstrate a propensity for the formation of stripe-like domains. Analogous to the vortex-like domains observed in ErMnO₃ single crystals, we find that the periodicity of the stripe-like domains depends on the cooling rate through the Curie temperature. For cooling rates in the range of 10⁻² to 10¹ K/min, the periodicity of the stripe-domains increases logarithmically. This scaling behavior is explained based on the interplay between cooling rate and long-ranging strain fields, offering new possibilities for the engineering of domains and domain walls in polycrystalline improper ferroelectrics.