Abstract The electrical properties of epitaxial lead titanate PbTiO 3 (PTO) and high T c superconductor Y 1Ba 2Cu 3O 7− x (YBCO) heterostructures have been studied by I– V and C– V techniques. The leakage current is identified to be controlled by the combination of Schottky and Frenkel–Poole effects. The dielectric constant is decreasing with increasing frequency. The loss tan δ is 0.051 at a frequency equal to 8200 Hz. Two sharp transition edges are observed in C– V curves, which we attribute to the domain switching process in the epitaxial single crystal PTO layer.