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Designing properties of (Na1/2Bix)TiO3-based materials through A-site non-stoichiometry

Frömling, Till and Steiner, Sebastian and Ayrikyan, Azatuhi and Bremecker, Daniel and Dürrschnabel, Michael and Molina-Luna, Leopoldo and Kleebe, Hans-Joachim and Hutter, Herbert and Webber, Kyle G. and Acosta, Matias (2018):
Designing properties of (Na1/2Bix)TiO3-based materials through A-site non-stoichiometry.
In: Journal of Materials Chemistry C, RSC Publishing, pp. 671-910, 6, (4), ISSN 2050-7526,
DOI: 10.1039/C7TC03975A,
[Article]

Abstract

Point defects largely determine the properties of functional oxides. So far, limited knowledge exists on the impact of cation vacancies on electroceramics, especially in (Na1/2Bi1/2)TiO3 (NBT)-based materials. Here, we report on the drastic effect of A-site non-stoichiometry on the cation diffusion and functional properties in the representative ferroelectric (Na1/2Bi1/2)TiO3–SrTiO3 (NBT–ST). Experiments on NBT/ST bilayers and NBT–ST with Bi non-stoichiometry reveal that Sr2+-diffusion is enhanced by up to six orders of magnitude along the grain boundaries in Bi-deficient material as compared to Bi-excess material with values of grain boundary diffusion ∼10−8 cm2 s−1 and ∼10−13 cm2 s−1 in the bulk. This also means a nine orders of magnitude higher diffusion coefficient compared to reports from other Sr-diffusion coefficients in ceramics. Bi-excess leads to the formation of a material with a core–shell microstructure. This results in 38% higher strain and one order of magnitude lower remanent polarization. In contrast, Bi-deficiency leads to a ceramic with a grain size six times larger than in the Bi-excess material and homogeneous distribution of compounds. Thus, the work sheds light on the rich opportunities that A-site stoichiometry offers to tailor NBT-based materials microstructure, transport properties, and electromechanical properties

Item Type: Article
Erschienen: 2018
Creators: Frömling, Till and Steiner, Sebastian and Ayrikyan, Azatuhi and Bremecker, Daniel and Dürrschnabel, Michael and Molina-Luna, Leopoldo and Kleebe, Hans-Joachim and Hutter, Herbert and Webber, Kyle G. and Acosta, Matias
Title: Designing properties of (Na1/2Bix)TiO3-based materials through A-site non-stoichiometry
Language: English
Abstract:

Point defects largely determine the properties of functional oxides. So far, limited knowledge exists on the impact of cation vacancies on electroceramics, especially in (Na1/2Bi1/2)TiO3 (NBT)-based materials. Here, we report on the drastic effect of A-site non-stoichiometry on the cation diffusion and functional properties in the representative ferroelectric (Na1/2Bi1/2)TiO3–SrTiO3 (NBT–ST). Experiments on NBT/ST bilayers and NBT–ST with Bi non-stoichiometry reveal that Sr2+-diffusion is enhanced by up to six orders of magnitude along the grain boundaries in Bi-deficient material as compared to Bi-excess material with values of grain boundary diffusion ∼10−8 cm2 s−1 and ∼10−13 cm2 s−1 in the bulk. This also means a nine orders of magnitude higher diffusion coefficient compared to reports from other Sr-diffusion coefficients in ceramics. Bi-excess leads to the formation of a material with a core–shell microstructure. This results in 38% higher strain and one order of magnitude lower remanent polarization. In contrast, Bi-deficiency leads to a ceramic with a grain size six times larger than in the Bi-excess material and homogeneous distribution of compounds. Thus, the work sheds light on the rich opportunities that A-site stoichiometry offers to tailor NBT-based materials microstructure, transport properties, and electromechanical properties

Journal or Publication Title: Journal of Materials Chemistry C
Volume: 6
Number: 4
Publisher: RSC Publishing
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Advanced Electron Microscopy (aem)
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
Date Deposited: 25 Jan 2018 12:25
DOI: 10.1039/C7TC03975A
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