Author/Authors :
Borowska-Centkowska، نويسنده , , A. and Kario، نويسنده , , A. and Krok، نويسنده , , F. and Abrahams، نويسنده , , I. and Chan، نويسنده , , S.C.M. and Liu، نويسنده , , X. and Wrobel، نويسنده , , W. and Malys، نويسنده , , M. and Hull، نويسنده , , S. and Dygas، نويسنده , , J.R. and Suard، نويسنده , , E.، نويسنده ,
Abstract :
An investigation of electrical conductivity and defect structure in the fluorite related system Bi3 + xNb0.8W0.2O7.1 + 3x/2 (0.0 ≤ x ≤ 2.0) using a.c. impedance spectroscopy and powder neutron diffraction is presented. All compositions exhibit incommensurate ordering of the cubic fluorite sublattice, with only the x = 2.0 composition showing evidence for an order–disorder transition above 650 °C. Non-linear behaviour in the thermal expansion of the cubic lattice parameter and the Arrhenius plot of total conductivity are discussed in terms of the defect structure.
Keywords :
defect structure , Neutron diffraction , Impedance spectroscopy , Bismuth oxide , Fluorite
