Pyroelectricity in PZT-based thick-films

The authors studied the pyroelectric properties of lead zirconate titanate (PZT)-based layers prepared with standard procedures of thick-film technol. (950° peak temperature) on an alumina substrate and with buried interdigital electrodes. The investigation was aimed at setting adequate procedures and at identifying sample configurations, for measuring the relevant pyroelectrical quantities rather than to optimize the material pyroelectrical performances. The results show that the pyroelectric coefficent of the authors' porous layers (approximately 1.2 +- 0.1 x 10-4 C/m2 K) is lower than that of the ceramic (approximately 3.8 x 10-4 C/m2 K) and dense thick films (approximately 2 x 10-4 C/m2 K) of comparable composition, but the thermal properties of their samples (low heat capacity and thermal cond.) as well as the low relative dielectric constant result in figures of merit better than the corresponding values either for ceramic PZT or other pyroelectic materials (including TGS and LiTaO3). Hence, the porous ferroelectric thick films are good candidates for new pyroelectric devices.