Influence of defects and domain walls on dielectric and mechanical resonances in LiNbO₃
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Publication Date
2015-12-07Alternative Title
Influence of defects and domain walls on dielectric and mechanical resonances in LiNbO3
Journal Title
Journal of Physics: Condensed Matter
ISSN
0953-8984
Publisher
IOP Science
Volume
28
Number
015901
Language
English
Type
Article
Metadata
Show full item recordCitation
Nataf, G., Aktas, O., Granzow, T., & Salje, E. (2015). Influence of defects and domain walls on dielectric and mechanical resonances in LiNbO₃. Journal of Physics: Condensed Matter, 28 (015901)https://doi.org/10.1088/0953-8984/28/1/015901
Abstract
Monodomain and periodically poled LiNbO₃ crystals (congruent composition) show dielectric and piezoelectric resonances between 100 K and 900 K. Dielectric measurements show resonances in some samples between 10-100 kHz. These resonances vanish under thermal anneal in monodomain crystals while they remain stable in periodically poled samples with high domain wall densities. The low activation energy of 0.18 eV suggests its electronic (bi-polaronic) origin. Resonant Piezoelectric Spectroscopy, RPS, shows two features in virgin samples: a relaxation peak at 450 K and a rapid hardening when the sample was slowly heated to ~ 500 K. The dynamic relaxation and the hardening are related to excitations and reorientations of Li defects. The relaxations and hardening are irreversibly suppressed by high temperature anneal. We do not observe domain wall related RPS resonances in annealed samples, which excludes the existence of highly charged walls. We suggest that domain walls stabilize polaronic states with (bi-)polarons located inside or nearby the ferroelectric domain walls.
Sponsorship
GFN and TG are grateful to National Research Fund (Luxembourg) for support (FNR/P12/4853155/Kreisel). EKHS is grateful to EPSRC for support (EP/K009702/1).
Funder references
EPSRC (EP/K009702/1)
Identifiers
External DOI: https://doi.org/10.1088/0953-8984/28/1/015901
This record's URL: https://www.repository.cam.ac.uk/handle/1810/252656
Rights
Creative Commons Attribution 4.0 International License
Licence URL: http://creativecommons.org/licenses/by/4.0/