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Electrical behaviour of Bi<inf>5</inf>FeTi<inf>3</inf>O<inf>15</inf> and its solid solutions with CaBi<inf>4</inf>Ti<inf>4</inf>O<inf>15</inf>

Abstract:

Pure Bi5FeTi3O15 and CaBi4Ti4O15 compounds and (1-x)Bi5FeTi3O15-xCaBi4Ti4O15, x = 0.25, 0.50, 0.75, solid solutions have been prepared by solid state reaction. Ceramics samples with apparent density >95% Dth have been sintered. Their crystalline structure have been determined by X-ray diffraction. Evolution of the lattice parameters has been evaluated. On the pure samples and solid solutions, electrical conductivity and Curie temperature Tc have been measured. Solid solution ceramics were poled and their piezoelectric parameters were established. Pure Bi5FeTi3O15 showed a high-electrical conductivity behaviour, like that of Bi4Ti3O12. Electrical conductivity of solid solutions decreases with the CaBi4Ti4O15 content. Poled ceramic samples showed moderate piezoelectric parameters, and very low values of dielectric loss. A possible conduction mechanism, which differs of that accepted for Bi4Ti3O12 is discussed. © 2002 Elsevier Science Ltd. and Techna S.r.l. All rights reserved.