Complex structural contribution of the morphotropic phase boundary in Na0.5Bi0.5TiO3 - CaTiO3 system
Affiliation auteurs | !!!! Error affiliation !!!! |
Titre | Complex structural contribution of the morphotropic phase boundary in Na0.5Bi0.5TiO3 - CaTiO3 system |
Type de publication | Journal Article |
Year of Publication | 2019 |
Auteurs | Roukos R, Dargham SAbou, Romanos J, Barakat F, Chaumont D |
Journal | CERAMICS INTERNATIONAL |
Volume | 45 |
Pagination | 4467-4473 |
Date Published | MAR |
Type of Article | Article |
ISSN | 0272-8842 |
Mots-clés | Dielectric properties, Morphotropic phase boundary, NBT-CT, Thermal hysteresis, X-ray diffraction |
Résumé | The correlation between structure and dielectric properties of lead-free (1-x)Na(0.5)Bia(5)TiO(3) - xCaTiO(3) ((1-x)NBT - xCT) polycrystalline ceramics was investigated systematically by X-ray diffraction, combined with impedance spectroscopy for dielectric characterizations. The system shows high miscibility in the entire composition range. A morphotropic phase boundary (MPB), at 0.09 <= x < 0.15 was identified where rhombohedral and orthorhombic symmetries coexist at room temperature. The fraction of orthorhombic phase increases gradually with x in the MPB region. Dielectric measurements reveal that the relative permittivity increase with addition of Ca2+. This behavior is unusual with this kind of doping. A thermal hysteresis occurred only in the MPB composition which varies in a non-monotonically manner with x, detected by dielectric properties. This phenomenon is related to the crystalline microstructure by a linear relationship between the fraction of each phase and dielectric properties, and, more precisely, to the strong interaction between rhombohedral and orthorhombic phases. |
DOI | 10.1016/j.ceramint.2018.11.126 |