Phase Transitions and Transport Properties of the Bismuth Vanadate-Based (Bi,La)₄(V,Zr)₂O_11-zCeramics

Abstract

Ceramic solid solutions (Bi 1−y La y ) 4 (V 1−x Zr x ) 2 O 11−z with x = 0-0.05, y = 0-0.16 have been prepared by the solid state reaction method. The samples were studied by differential thermal analysis, X-ray diffraction, dielectric spectroscopy, and impedance methods. The concentration and temperature stabilization regions of the polymorphous α-, β-, γ'-, γ-modifications have been determined. The effects observed in dielectric properties, conductivity, and impedance data confirmed the influence both of intrinsic oxygen vacancies and those "pinned" at ferroelectric domain boundaries on the temperature hysteresis of α-β phase transition and their contribution to mechanism of oxygen ion transport.

Crystal structure and phase transition in the doped super‐ionic conductor bismuth vanadate Bi4(V,Fe)2O11 revealed by neutron diffraction

“…A lot of efforts was undertaken to stabilize the γ‐phase at temperatures as low as possible, mainly through the doping of parent compounds with various cations. Different cation modifications were studied, particularly, the vanadium substituted compounds ${\rm Bi}_{4} ({\rm V}_{1- x} ,\kern 1pt {\rm Me}_{x} )_{2} \kern 1pt {\rm O}_{11- y} $ , (Me – substituting ion) 4, 12–45. However, despite of the numerous studies, the crystal structure of Bi 4 V 2 O 11− y and its polymorphs is still not completely understood due to complexity and variation with doping.…”