Ferroelectricity in thin perovskite films

We report on the investigation of ferroelectricity in thin tetragonal singl e-crystalline perovskite films of Pb(Zr0.2Ti0.8)O-3 grown by off-axis rf ma gnetron sputtering. The local ferroelectric properties of atomically smooth films, with thicknesses ranging from a few unit cells to 800 Angstrom, wer e measured using a combination of electric force microscopy and piezoelectr ic microscopy. The time dependence of the measured signals reveals a stable ferroelectric polarization in films down to thicknesses of 40 Angstrom. (C ) 1999 American Institute of Physics. [S0003-6951(99)01932-4].