Investigation of structural and electrical characteristics of PZT ceramics modified with donor and acceptor dopants

Abstract

Lead-based (PZT) ferroelectric ceramic materials were prepared utilizing the solid-state reaction method as a pure and doped with different additives. As a pure form, the composition with the chemical formula Pb_1.03(Zr_0.56Ti_0.44)O₃ characterized as rhombohedral structure according to the PZT phase diagram region was investigated systematically. Different strategies of doping were followed to investigate the influence of donor and acceptor ions in addition to complex doping on structural and microstructure properties of the parent composition: for the soft ceramic, 2 mol% lanthanum-doped PZT at A-site (PLZT), whereas 2 mol% of scandium-doped PZT at B-site to produce hard ceramic (PSZT). In terms of complex doping, 2 mol% of both La³⁺ and Sc³⁺ substituted A- and B-site, respectively (PLSZT). All samples showed dense and homogeneous microstructures, except PSZT ceramic displayed a small grain size. X-ray diffraction results showed that the addition of Sc³⁺ induced phase transformation and formation of a coexistence region consisting of tetragonal and rhombohedral phases. This region was recognized in both PSZT and PLSZT compositions. Hard ceramic (Sc³⁺-doped PZT) exhibited the highest values of relative permittivity and lowest dielectric loss at a frequency of 100 kHz.

Keywords:
lead-based ceramics; ferroelectrics; phase transformation; dielectrics