Dielectric properties of Pb0.5Ca0.5TiO3 thin films

A dielectric study is carried out on chemical solution-deposited calcium lead titanate (Pb,Ca)TiO3 thin films, with calcium contents of 50 at. %, by measuring capacitance versus voltage as a function of temperature. A moderate ferroelectric activity is observed that remains in a broad temperature range, and that depends on the applied voltage and thickness of the films. This behavior is associated with the built-in fields generated as result of the space charge inside the films. From the diffusivity of dielectric constant versus temperature (K′−T) curves, the relaxorlike nature of the films is also demonstrated. The feasibility of these films for fabrication of voltage tuneable capacitors and charge store devices (dynamic random access memories) is confirmed.