Electrical and Pyroelectric Properties of Sol-Gel Derived (Pb,Ca)TiO₃ Thin Films with Various Orientations

(Pb_0.76Ca_0.24)TiO₃ (PCT) thin films with various orientations were grown on Pt/Ti/SiO₂/Si substrates by using a sol-gel process and by controlling the temperature of heat-treatment. The PCT thin films with (100) and random orientation showed well-saturated hysteresis loops at an applied field of 800 kV/cm, with remanent polarisation and coercive electric field of 23.6 μC/cm² and 225kV/cm, 17.8 μC/cm² and 195 kV/cm, respectively. For highly (100)- and random-oriented PCT films, the dielectric constant and dielectric loss values of these films are 121 and 0.016, 121 and 0.024 at 1 kHz, respectively. The pyroelectric coefficients p of the PCT thin films are measured by a dynamic technique. At room temperature, the p values and figures of merits of the highly (100)- and random-oriented PCT films are 185 μC/m²K and 1.79 xm 10^-5Pa^-0.5, 176μC/m²K and 1.39 x 10^-5Pa^-0.5, respectively.