CORRELATION OF DEFECT STRUCTURE AND IONIC CONDUCTIVITY IN FLUORITE SOLID SOLUTIONS IN THE PSEUDO-BINARY SYSTEM Bi2O3-YNbO4

摘要

Structure and conductivity are investigated in the pseudo-binary system Bi2O3-YNbO4 in compositions of general formula (Bi2O3)1-x(YNbO4)x using a.c. impedance spectroscopy and X-ray and neutron powder diffraction. A cubic/pseudo-cubic solid solution is observed in bismuth rich compositions. In the solid solution region, the oxide ion distribution exhibits both compositional and thermal dependence, which can be correlated with changes in the activation energy for total conductivity and non-linear behaviour in the thermal expansion of cubic lattice parameter.