Structural and dielectric properties of Sb-doped PLZT ceramics

Lead Zirconate Titanate (PZT), a member of ABO3 (A = mono or divalent, B = tri to pentavalent ions) family is a solid solution of lead titanate and lead zirconate ceramics. PZT ceramics with compositions near Morphotropic Phase Boundary (MPB) offer good ferroelectric, piezoelectric and electrical properties. It is well established that the substitution of La3+ at the Pb site of PZT (PLZT) gives improved optoelectronic and piezoelectric properties of the materials. In most of the complex PLZT compounds (by increasing the La content in Zr or Ti rich compounds) broadened dielectric peaks or diffuse phase transitions with relaxation character in the transition temperature have been observed. For better understanding of the diffuse phase transition on double doping at the Pb site of PLZT near the MPB and the changes in physical or device parameters, we have carried out systematic studies on structural and dielectric properties of the compounds. In this paper, we report the study of the effect of paired dopants (La and Si) in PZT ceramics. Samples of Sb-doped PLZT were synthesized by high-temperature solid-state solution reaction technique. Preliminary crystal structure and microstructure of the compounds were studied by X-ray diffraction technique. Detailed dielectric studies of the samples suggest that they undergo ferroelectric paraelectric diffuse phase transition. Temperature dependence of dc resistivity of the compounds exhibits Negative Temperature Coefficient Resistance behavior.