Effects of Ca Doping on Structural and Optical Properties of PZT Nanopowders

Abstract The influence of the addition of calcium ions (Ca2+) in the Pb(1-x)CaxZr0.52Ti0.48O3 system (PCZT) for x =0.05, 0.10, 0.15, 0.20, and 0.25 on the structural and optical properties was systematically studied. The compositions were synthesized through a polymerized-complex approach based on the Pechini polymeric precursor route. The solubility limit of calcium ions within the PCZT lattice is in between x=0.10 and x=0.15, at which a CaTiO3 secondary phase is detected. The Goldschmidt tolerance factors, modified tolerance factors, and the effective vacancy sizes were all estimated for the synthesized nanopowders. While the Goldschmidt tolerance factors suggest the formation of a distorted perovskite structure, the values of the modified tolerance factor were extremely close to unity, indicating a strong stable ferroelectric perovskite structure. The optical band gap was found to decrease with calcium concentration to a minimum at x=0.20 and then slightly increase at x=0.25.