Regensburg 2019 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 10: Ferroics - Domains and Domain Walls
KFM 10.3: Talk
Tuesday, April 2, 2019, 10:00–10:15, H47
Tuning ferroelectric phase transition temperatures in epitaxial KxNa1−xNbO3 thin films — •Leonard von Helden1, Laura Bogula1, Pierre-Eymeric Janolin2, Michael Hanke3, Martin Schmidbauer1, and Jutta Schwarzkop1 — 1Leibniz Institute for Crystal Growth, Berlin, Germany — 2Laboratoire SPMS, CNRS-École Centrale Paris, France — 3Paul-Drude-Institute for Solid State Electronics, Berlin, Germany
KxNa1−xNbO3 is a promising material for, e.g., surface acoustic wave (SAW) sensors based on ferroelectric thin films. For these systems a strong enhancement of SAW transmission coefficients in the vicinity of phase transition temperatures has been reported, recently.[1] Hence, it is desirable to deliberately tune those phase transitions.
Here, we present a first systematic study in which ferroelectric phase transition temperatures in epitaxial KxNa1−xNbO3 films could be altered by choice of different (110) oriented rare earth scandate substrates and variation of the K-to-Na ratio in the film. Sample preparation was conducted by liquid delivery metal organic vapor phase epitaxy (MOVPE). Our results reveal the possibility to continuously shift the ferroelectric-ferroelectric transition between monoclinic MC and c-phase by about 400 K via application of compressive strain. The phase transition was investigated in detail by temperature dependent piezoresponse force microscopy (PFM), X-ray diffraction (XRD) and laser interferometry.
[1] S. Liang et al., Appl. Phys. Lett. 113, 052901 (2018)