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Symmetry of domain walls and its relation to macroscopic properties
1
W. Schranz1*,
University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Wien, Austria
*e-mail: [email protected]
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).
Curriculum Vitae
http://homepage.univie.ac.at/Wilfried.Schranz
Wilfried Schranz was born in1960 in Oberwart/Burgenland in Austria.
He received his PhD 1988 at the University of Vienna (Theory of incommensurate phases
in biphenyl). After his habilitation (1994) in solid state physics he obtained a professorship
at the Faculty of Physics of the University of Vienna (1997).
His major research expertise is on ferroic phase transformations, domains and domain
walls, studying also the elastic and anelastic properties of materials. His main scientific
achievements concern the study of mesoscopic phenomena using acoustic spectroscopy.
Among his most significant findings are the discovery of heat-diffusion central peak in
elastic susceptibility [PRL 73, 2575 (1994)], the giant elastic softening due to soliton
motion in incommensurate crystals [PRB 53, 6337 (1996)] as well as the domain wall
induced superelastic softening in perovskites [PRB 83, 094120 (2011)].
He is co/author of more than 190 papers and co/organizer of international conferences
(DyProSo, ISFD, etc.) and workshops (TMR, ESF, etc.). He delivered more than 80 invited
talks at international conferences and research institutions.
He was elected as Adjunct professor for the period 2006/2009 in the Department of
Nanosciences and Nanotechnologies at the Jozef Stefan International Postgraduate
School, Ljubljana, Slowenia.