Influence of defects and domain walls on dielectric and mechanical resonances in LiNbO$_3$

Guillaume F Nataf; Oktay Aktas; Torsten Granzow; Ekhard K. H. Salje

doi:10.1088/0953-8984/28/1/015901

Influence of defects and domain walls on dielectric and mechanical resonances in LiNbO$_3$

Guillaume F Nataf ^{1, 2} Oktay Aktas ^{3, 4} Torsten Granzow ² Ekhard K. H. Salje ^{2, 3, *}

* Auteur correspondant

1 LENSIS - Laboratoire d'Etude des NanoStructures et Imagerie de Surface

SPEC - UMR3680 - Service de physique de l'état condensé, IRAMIS - Institut Rayonnement Matière de Saclay

2 Materials Research and Technology (MRT) Department, Luxembourg Institute of Science and Technology (LIST)

3 Department of Earth Sciences [Cambridge, UK]

4 ETH Zurich - Department of Computer Science

Abstract : Monodomain and periodically poled LiNbO$_3$ 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 their electronic (bi-polaronic) origin. Resonant piezoelectric spectroscopy, RPS, shows two features in virgin samples: a relaxation peak at 420 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 near to the ferroelectric domain walls.

Type de document :

Article dans une revue

Journal of Physics: Condensed Matter, IOP Publishing, 2015, 28, pp.015901. 〈10.1088/0953-8984/28/1/015901〉

Domaine :

Physique [physics]

Liste complète des métadonnées

https://hal-cea.archives-ouvertes.fr/cea-01550765
Contributeur : Dominique Girard <>
Soumis le : jeudi 29 juin 2017 - 17:32:28
Dernière modification le : jeudi 15 mars 2018 - 15:04:53

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