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Criticality : concept to enhance the piezoelectri and electrocaloric properties of ferroelectrics

Weyland, Florian and Acosta, Matias and Koruza, Jurij and Breckner, Patrick and Rödel, Jürgen and Novak, Nikola (2016):
Criticality : concept to enhance the piezoelectri and electrocaloric properties of ferroelectrics.
In: Advanced Functional Materials, pp. 7326-7333, ISSN 1616-301X, [Article]

Abstract

Compositional engineering with a focus on structural phase transitions has been considered as the most important approach for enhancement of the functional properties of ferroelectric materials due to the critical fluctuation of physical properties. Of special interest are electric-field-induced phase transitions, which can terminate in a liquid–vapor-type critical point with a strong enhancement of functional properties. Whereas the critical point in liquid–vapor space considers changes in temperature and pressure, the critical point in this study is placed in electric field–temperature diagrams. In single crystals, temperature and electric field of a critical point are sharply defined and therefore not appealing for practical applications. However, in ceramics, it is demonstrated that the orientational dependence of the critical point leads to a broadened temperature and electric field range. The presence of a diffuse critical point in ceramics provides a conceptually novel approach for the enhancement of functional properties, such as piezoelectric and electrocaloric(EC) responses, as validated here on the example of the 0.75Bi1/2Na1/2TiO3- 0.25SrTiO 3 lead-free relaxor ferroelectric ceramics. The realization of a broad criticality range will further facilitate the development of the piezoelectric and EC materials and provide an alternative concept to manipulate the functional properties by application of an electric field.

Item Type: Article
Erschienen: 2016
Creators: Weyland, Florian and Acosta, Matias and Koruza, Jurij and Breckner, Patrick and Rödel, Jürgen and Novak, Nikola
Title: Criticality : concept to enhance the piezoelectri and electrocaloric properties of ferroelectrics
Language: English
Abstract:

Compositional engineering with a focus on structural phase transitions has been considered as the most important approach for enhancement of the functional properties of ferroelectric materials due to the critical fluctuation of physical properties. Of special interest are electric-field-induced phase transitions, which can terminate in a liquid–vapor-type critical point with a strong enhancement of functional properties. Whereas the critical point in liquid–vapor space considers changes in temperature and pressure, the critical point in this study is placed in electric field–temperature diagrams. In single crystals, temperature and electric field of a critical point are sharply defined and therefore not appealing for practical applications. However, in ceramics, it is demonstrated that the orientational dependence of the critical point leads to a broadened temperature and electric field range. The presence of a diffuse critical point in ceramics provides a conceptually novel approach for the enhancement of functional properties, such as piezoelectric and electrocaloric(EC) responses, as validated here on the example of the 0.75Bi1/2Na1/2TiO3- 0.25SrTiO 3 lead-free relaxor ferroelectric ceramics. The realization of a broad criticality range will further facilitate the development of the piezoelectric and EC materials and provide an alternative concept to manipulate the functional properties by application of an electric field.

Journal or Publication Title: Advanced Functional Materials
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: 28 Oct 2016 10:26
Identification Number: doi:10.1002/adfm.201602368
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