DIELECTRIC-PROPERTIES OF LANTHANUM, CADMIUM OR NIOBIUM SUBSTITUTED BI3PB4SB5O21 SOLID-SOLUTIONS

Lanthanum, cadmium or niobium substituted-Bi3Pb4Sb5O21 solid solutions have been synthesized by solid state reaction. The limiting compositions and the evolution of the lattice parameters as a function of the ionic radii of the substituting elements have been determined. Low frequency dielectric properties (dielectric constants and losses, temperature coefficient of the dielectric constants) have been measured between room temperature and 373 K on sintered ceramic samples. Their variations are discussed in terms of the electronic structures of the involved cations and the relative polarisabilities of both NbO6 and SbO6 octahedra. © 1990.