Ceramics-Silikáty 54 (4) 303-309 (2010)

MnO₂ MODIFIED LEAD LANTHANUM SILVER ZIRCONIUM TITANATE CERAMICS FOR DIELECTRIC AND PIEZOELECTRIC PROPERTIES

K. Ramam , K. Chandramouli

This study highlights the influence of acceptors, Ag at A-site and Mn at B-site in Pb_(1-x-y)La_xAg_y(ZrzTi_{1-z)1-((x-y)/4)-(4k/4)}Mn_kO₃ ceramic system where Mn (k) ranged from 0, 0.2, 0.4. 0.6, 0.8 and 1 mol% synthesized through solid state reaction method. Dielectric (ε_RT = 2802) and piezoelectric properties (d₃₃ = 548 pC/N, k_p = 0.541) were maximum at Mn0.01 and can be attributed to (1) grain boundary kinetics via domain orientation with a reduction of oxygen vacancy migration, (2) compensation of lead vacancies by Mn and Ag, and (3) morphotrophic phase boundary shifting from coexistence of rhombohedral and tetragonal phase to tetragonality. The high electromechanical properties of this ceramic system were evaluated and are discussed with phase formation, microstructure, and dielectric characterization. It has been observed that the optimum properties are found in Mn_0.01 which could be suitable for possible energy harvesting or electromechanical applications.

Keywords: Ceramics; Microstructure; Dielectric properties; Piezoelectricity