The effect of grain size on unit-cell dimensions and dielectric properties has been studied in ceramic lanthana-substituted leadtitanate and leadtitanate-zirconate mixed crystals of the general composition Pb1−αxLaxZryTi1−yO3+x(1.5−α). The influence of grain size has been investigated in the range from 0.6μm–10μm and can be distinguished from other microstructural influences by its effect on dielectric properties. A decrease of the grain size leads to a decrease of the maximum of the dielectric constant ε′ at the “Curie” temperature Tc′, while the value of Tc′ shifts to a lower temperature and the ε′-T curve (phase transition) becomes broadened. The results can be discussed in terms of a distribution of internal compression stresses spreading around an average value which increases with decreasing grain size.
Burggraaf, A. J., & Keizer, K. (1975). Effects of microstructure on the dielectric properties of lanthana substituted PbTiO3 and Pb (Zr, Ti) O3-ceramics. Materials research bulletin, 10(6), 521-528. https://doi.org/10.1016/0025-5408(75)90177-4