Ferroelectric and pyroelectric characteristics of A site Nb+5 doped PZT

Nb⁺⁵ doped PZT ceramic has been prepared by conventional solid solution technique. The doping has been carried out at A-site by varying the dopant concentration from 2.5% to 7.5%. The X-ray diffractograms of these samples show tetragonality with c/a ratio close to unity. The dielectric measurements do not show any Curie transition upto 160°C. It was found that the dielectric constant at room temperature initially increases as Niobium concentration increases from 2.5 to 4% and then starts decreasing upto 7.5 atom percent of Niobium. Hysteresis phenomena in these samples was studied to ascertain the ferroelectric nature of the specimens. These samples were corona poled and their piezo and pyroelectric properties were measured. Pyrocoefficient (P_s), saturation polarization (P_s) and remanent polarization show maximum values of 10 nC/cm²°C, 17 μC/cm² respectively at around 4 atom% of niobium concentration. These values of P_s and P, coupled with low dielectric permittivity and loss suggests that A-site Nb⁺⁵ doped PZT may find useful applications in pyroelectric detectors