Diffuse phase transition and leakage current characteristics of (Pb0.25Sr0.75)TiO3 thin films prepared by a sol–gel process

Nanocrystalline (Pb0.25Sr0.75)TiO3 (PSrT25) thin films were grown on Pt/Ti/SiO2/Si substrates by using a sol–gel process. The dielectric constant and loss tanδ of Au/PSrT/Pt thin-films capacitor were 345 and 0.016 at 100 kHz, respectively. The dielectric constant of PSrT film changes significantly with applied dc bias field and has a tunability of 22.7 % under an applied field of 150 kV/cm. Phase transition of the PSrT25 film has shown the diffuse-type phase transition behavior. The leakage current varied depending on the voltage polarity. At low electrical field and with Au electrode biased negatively, the Au/PSrT interface exhibits a Schottky emission characteristic, while at higher fields, Poole–Frenkel dominated the electronic conduction.