Ferroelectric BaTiO3thin films were directly and epitaxially grown on SrTiO3single crystal and epitaxial Pt film substrates by activated reactive evaporation. The substrate temperature was around 600 °C. For (100) oriented as‐grown films, a typical ferroelectric hysteresis loop and a maximum of dielectric constant at about 115 °C were observed. The resistivity was as high as 109&OHgr; cm and the breakdown voltage was 2.7 MV/cm for as‐grown BaTiO3films.