Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 7: Focus Session: Defects and Interfaces in Multiferroics 2

KFM 7.5: Vortrag

Montag, 5. September 2022, 16:45–17:05, H5

Oxygen off-stoichiometry and domain wall conductance in ErMnO₃ — •Leonie Richarz¹, Jan Schultheiß¹, Edith Bourret^2,3, Zewu Yan³, Antonius T.J. van Helvoort¹, and Dennis Meier¹ — ¹NTNU Norwegian University of Science and Technology, Trondheim, Norway — ²ETH Zurich, Switzerland — ³Lawrence Berkeley National Laboratory, Berkeley, CA, USA

Ferroelectric domain walls are natural interfaces, separating volumes with different orientation of the spontaneous polarization. Due to their symmetry, electrostatics, and strain, the walls can develop completely different electronic properties than the surrounding domains. In ferroelectric oxides, oxygen off-stoichiometry is an additional versatile control parameter. This is reflected by the neutral ferroelectric domain walls in hexagonal manganites: Depending on the oxygen content, their conduction behavior varies from insulating to highly conducting.

In this work, we monitor the electronic transport properties at the domain walls as a function of temperature and oxygen partial pressure with nanoscale spatial resolution. Conductive atomic force microscopy measurements on high-quality ErMnO₃ single crystals show anomalous conductance at the domain walls within the whole temperature range of 25 to 300^∘C. Furthermore, we find that by annealing the sample in nitrogen, the domain wall conductance can be enhanced. Our results provide new insight into the impact of environmental parameters on the electronic domain wall properties. This is of interest for the development of atmospheric sensors, adding a new direction to the field of domain wall nanotechnology.