Temperature-induced local and average structural changes in BaTiO3−xBi(Zn1/2Ti1/2)O3 solid solutions: The origin of high temperature dielectric permittivity

• Published in: Journal of applied physics 2017-08, Vol.122 (6)
• Main Authors: Hou, Dong, Usher, Tedi-Marie, Zhou, Hanhan, Raengthon, Natthaphon, Triamnak, Narit, Cann, David P., Forrester, Jennifer S., Jones, Jacob L.
• Format: Article
• Language: English
• Subjects: Applied physics; Barium titanates; Clusters; Dielectric relaxation; Freight cars; High temperature; Lead free; Permittivity; Perovskites; Relaxors; Solid solutions; Thermal stability
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4989393

The existence of local tetragonal distortions is evidenced in the BaTiO3–xBi(Zn1/2Ti1/2)O3 (BT–xBZT) relaxor dielectric material system at elevated temperatures. The local and average structures of BT-xBZT with different compositions are characterized using in situ high temperature total scattering techniques. Using the box-car fitting method, it is inferred that there are tetragonal polar clusters embedded in a non-polar pseudocubic matrix for BT-xBZT relaxors. The diameter of these polar clusters is estimated as 2–3 nm at room temperature. Sequential temperature series fitting shows the persistence of the tetragonal distortion on the local scale, while the average structure transforms to a pseudocubic paraelectric phase at high temperatures. The fundamental origin of the temperature stable permittivity of BT-xBZT and the relationship with the unique local scale structures are discussed. This systematic structural study of the BT-xBZT system provides both insight into the nature of lead-free perovskite relaxors, and advances the development of a wide range of electronics with reliable high temperature performance.