La3+ substitution induced structural transformation in CaBi4Ti4O15 Aurivillius phases: Synthesis, morphology, dielectric and optical properties
Autor: | Zulhadjri, Rini Ramadhani, Tio Putra Wendari, Yulia Eka Putri, Imelda |
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Rok vydání: | 2021 |
Předmět: |
010302 applied physics
Phase transition Materials science biology Process Chemistry and Technology Transition temperature 02 engineering and technology Dielectric 021001 nanoscience & nanotechnology biology.organism_classification 01 natural sciences Ferroelectricity Surfaces Coatings and Films Electronic Optical and Magnetic Materials Aurivillius Crystallography Phase (matter) 0103 physical sciences Materials Chemistry Ceramics and Composites Orthorhombic crystal system 0210 nano-technology Lone pair |
Zdroj: | Ceramics International. 47:23549-23557 |
ISSN: | 0272-8842 |
Popis: | In this work, La-substituted CaBi4Ti4O15 Aurivillius phase, CaBi4-xLaxTi4O15 (x = 0, 0.5, 1, 1.5, and 2), were synthesized by a molten salt method. The effects of La3+ substitution on structure, morphology, dielectric and optical properties were systematically investigated. Refinement of XRD data confirm that a ferroelectric orthorhombic structure with space group A21am was adopted for x = 0, 0.5, 1, and 1.5. In terms of x = 2, the structure transformed to an intermediate paraelectric orthorhombic structure of the Amam space group. The anisotropic plate-like grains were observed across all the samples, which decreased in size with an increase in La3+ content. With La3+ substitution, the ferroelectric transition temperature (Tc) significantly decreased since the structural distortion as the effect of 6s2 lone pair electron of Bi3+ was reduced with the substitution of La3+. Additionally, the reduced structural distortion was responsible for a decrease in the bandgap (Eg) energy. A diffused phase transition of ferroelectric characterized by the broadened Tc peak was induced by La3+ substitution since the increased disorder of A-site cation (Ca/Bi/La). The ferroelectric phase with a lower Tc and the lower Eg energy proposes the sample of x = 1.5 as a potential material for electrocaloric and solar cell applications. |
Databáze: | OpenAIRE |
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