Beschreibung
Given their small size as well as the fact that their internal structures and properties can be very different from the surrounding bulk material, domain walls may play an important role in future devices. E.g. in CaTiO3 a ferroelectric polarization1 inside a ferroelastic twin wall was observed although the rest of the crystal remained centrosymmetric. While such observations can be most conveniently described by the use of layer groups2,3, a systematic way to calculate the corresponding couplings in a Landau-Ginzburg free energy is still missing. Also the dynamic behaviour of twin walls under external forcing depends sensitively on the structure of the wall4,5. In this talk we will present results, demonstrating how the macroscopic response is influenced by the properties of domain walls6 and discuss some open problems. 1. Direct Observation of Ferrielectricity at Ferroelastic Domain Boundaries in CaTiO3 by Electron Microscopy, S. Van Aert, S. Turner, R. Delville, D. Schryvers, G. Van Tendeloo and E. K. H. Salje, Adv. Mater. 24, 523 (2012). 2. A symmetry approach to domain structures, V. Janovec, Ferroelectrics 12, 43 (1976). 3. Symmetry analysis of domain structure in KSCN crystals, V. Janovec, W. Schranz, H. Warhanek and Z. Zikmund, Ferroelectrics 98,171 (1989). 4. Ferroelastic domain switching dynamics under electrical and mechanical excitations, P. Gao, et al. Nature Communications 5, 3801 (2014). 5. Highly mobile vortex structures inside polar twin boundaries in SrTiO3, T. Zykova-Timan and E.K.H. Salje, Applied Phys. Lett. 104, 082907 (2014). 6. Giant domain wall response of highly twinned ferroelastic materials, W. Schranz, H. Kabelka, A. Sarras and M. Burock, Appl. Phys. Lett. 101, 141913 (2012).| Zeitraum | 16 Okt. 2015 |
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| Gehalten am | Fakultät für Geowissenschaften, Geographie und Astronomie |