The effect of microstructure on the pyroelectric properties of PZT ceramics

Lead titanate zirconate ceramics with a base composition PbTixZr1−xO3 with x=0.07 was pressure sintered, starting from mixed oxide powders. The effects of sintering time on the microstructure, on the dielectric constant and pyroelectric properties of the resulting ceramics are reported and discussed. It is found the pyroelectric properties are strongly influenced by sintering times and hence microstructure. The results indicate that as the grain sizes increase the dielectric constant and the Curie temperature increases, while the pyroelectric current decreases. The temperatures that the total pyroelectric coefficients due to primary and secondary effects change sign and directions of spontaneous polarization have been also reported. The measured pyroelectric coefficients show also some fluctuation, but for low temperature the samples with large grain size are more stable.