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Relaxor-ferroelectric crossover in (Bi1/2K1/2)TiO3: Origin of the spontaneous phase transition and the effect of an applied external field

Hagiwara, M. and Ehara, Yoshitaka and Novak, Nikola and Khansur, Neamul H. and Ayrikyan, Azatuhi and Webber, Kyle G. and Fujihara, Shinobu (2017):
Relaxor-ferroelectric crossover in (Bi1/2K1/2)TiO3: Origin of the spontaneous phase transition and the effect of an applied external field.
In: Physical Review B, American Physical Society, pp. 1-9, 96, (014103), ISSN 1098-0121, DOI: 10.1103/PhysRevB.96.014103, [Article]

Abstract

The temperature evolution of polar order in an A-site complex perovskite (Bi1/2K1/2)TiO3 (BKT) has been investigated by measurements of dielectric permittivity, depolarization current, and stress-stain curves at elevated temperatures. Upon cooling from high temperatures, BKT first enters a relaxor state and then spontaneously transforms into a ferroelectric state. The analyses of temperature and frequency dependence of permittivity have revealed that polar nanoregions of the relaxor phase appear at temperatures higher than 560 ◦C, and also that their freezing at 296 ◦C triggers the spontaneous relaxor-ferroelectric transition.We discuss the key factors determining the development of long-range polar order in A-site complex perovskites through a comparison with the relaxor (Bi1/2Na1/2)TiO3. We also show that application of biasing electric fields and compressive stresses to BKT favors its ferroelectric phase, resulting in a significant shift of the relaxor-ferroelectric transition temperature towards higher temperatures. Based on the obtained results, electric field-temperature and stress-temperature phase diagrams are firstly determined for BKT.

Item Type: Article
Erschienen: 2017
Creators: Hagiwara, M. and Ehara, Yoshitaka and Novak, Nikola and Khansur, Neamul H. and Ayrikyan, Azatuhi and Webber, Kyle G. and Fujihara, Shinobu
Title: Relaxor-ferroelectric crossover in (Bi1/2K1/2)TiO3: Origin of the spontaneous phase transition and the effect of an applied external field
Language: English
Abstract:

The temperature evolution of polar order in an A-site complex perovskite (Bi1/2K1/2)TiO3 (BKT) has been investigated by measurements of dielectric permittivity, depolarization current, and stress-stain curves at elevated temperatures. Upon cooling from high temperatures, BKT first enters a relaxor state and then spontaneously transforms into a ferroelectric state. The analyses of temperature and frequency dependence of permittivity have revealed that polar nanoregions of the relaxor phase appear at temperatures higher than 560 ◦C, and also that their freezing at 296 ◦C triggers the spontaneous relaxor-ferroelectric transition.We discuss the key factors determining the development of long-range polar order in A-site complex perovskites through a comparison with the relaxor (Bi1/2Na1/2)TiO3. We also show that application of biasing electric fields and compressive stresses to BKT favors its ferroelectric phase, resulting in a significant shift of the relaxor-ferroelectric transition temperature towards higher temperatures. Based on the obtained results, electric field-temperature and stress-temperature phase diagrams are firstly determined for BKT.

Journal or Publication Title: Physical Review B
Volume: 96
Number: 014103
Publisher: American Physical Society
Divisions: 11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
11 Department of Materials and Earth Sciences
Date Deposited: 11 Jul 2017 05:38
DOI: 10.1103/PhysRevB.96.014103
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