Formation Kinetics of a Bi3Nb1−xTaxO7 Fluorite-Type Solid Solution and Thermodynamic Stability of the Bi3TaO7 End Member
Abstract:Analysis of kinetic characteristics of the incommensurate—commensurate transformation in the Bi3Nb1−xTaxO7 system with a fluorite-like crystal structure enabled us to define the compositional and thermal stability ranges of the commensurate tetragonal polymorph. We showed that the tetragonal polymorph across the entire homogeneity range is isostructural to the Bi3NbO7 end member. The kinetics of the transformation from the cubic incommensurate to the tetragonal commensurate phase decreases with an increase in Ta concentration within the Bi3Nb1−xTaxO7 system. The formation studies indicate that the tetragonal Bi3TaO7 is thermodynamically stable; however, its formation via the metastable incommensurate-cubic phase is suppressed.
Document Type: Research Article
Affiliations: 1: Material Research Laboratory, University of Nova Gorica, 5000 Nova Gorica, Slovenia 2: Lawrence Berkeley National Laboratory, National Centre for Electron Microscopy, Berkeley, California 94720
Publication date: 2010-09-01