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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 10: Ferroics - Domains and Domain Walls

KFM 10.8: Vortrag

Dienstag, 2. April 2019, 11:50–12:05, H47

Local manipulation of improper ferroelectric domains in YMnO₃ using scanning probe microscopy at low temperatures — •L. Kuerten¹, P. Schoenherr¹, S. Krohns², D. Meier³, E. Pomjakushina⁴, K. Conder⁴, Th. Lottermoser¹, and M. Fiebig¹ — ¹Department of Materials, ETH Zurich — ²Experimental Physics V, University of Augsburg — ³Department of Materials Science and Engineering, NTNU, Trondheim — ⁴Laboratory for Scientific Developments and Novel Materials, PSI, Villigen

In hexagonal manganites, the conductivity can differ by orders of magnitude between ferroelectric domains and domain walls. In order to utilize this technological potential, control over the domain wall position and orientation is necessary. In YMnO₃, switching of the bulk polarization has been achieved at low temperatures using co-planar electrodes. However, the microscopic mechanism of domain switching and the role played by domain wall motion and domain nucleation are still unknown. In particular, the multi-domain state of the surface appears unaffected when observed at room temperature before and after switching. Here, we investigate the microscopic mechanism of domain manipulation in situ at low temperature using piezoresponse force microscopy (PFM). By applying DC voltages to the PFM tip, we reveal signatures of polarization reversal at the sample surface indicating local domain switching. However, charge injection via the tip also plays a crucial role, which is demonstrated for regions on the nanometer scale. These charged regions remain stable for days at low temperatures, but vanish for increased temperatures.