The results of this study are summarized as follows:
(1) High density lanthanum-modified lead zirconate titanate (PLZT) ceramics with compositions of {(Pb0.925La0.075)(ZryTi1-y)0.981O3+0.5 mass% MnO2}, where y=0-0.10, were successfully synthesized by hot isostatic pressing.
(2) All the pressed samples had the high relative density of 99.9% of theoretical density.
(3) The relative dielectric constant εr at room temperature was in the range of 290 to 334 which was satisfactory for requirements of maintaining appropriately low εr(-350).
(4) The rates of linear increase m1 and decrease m2 calculated from the slope of the linear plot of εr and the Curie temperature TC with y were approximately 4.0/mol% Zr and 0.6°C/mol% Zr, respectively.
(5) Assuming that the volume specific heat Cv of the PLZT samples with y=0-0.10 are 3.2×106J/m3·K, y=0.10 PLZT sample exhibited the highest figures of merit F.M. for voltage responsivity of around 0.20×10-12C·m/J and F.M.D* for specific detectivity D* of around 0.57×10-10C·m/J, among the nine samples studied here.
(6) The figure of merit F.M.D* of y=0.10 PLZT sample matched εr of element materials with those of FET used in the sensor circuit was superior to those of PLZT(4/44/56) ceramic and x=0.005 PLMT ceramic that have been previously reported.
