The 0.65Pb(Mg1/3Nb2/3) O-3-0.35PbTiO(3) (PMN-PT) epitaxial thin films were grown on LaNiO3/CeO2/yttria-stabilized zirconia buffered Si(001) substrates at 600 degrees C in a working pressure of 300 mTorr using pulsed laser deposition. The microstructural and the electrical properties of the films were investigated as a function of the film thickness. The high resolution x-ray diffraction and transmission electron microscopy results reveal that the 800-nm thick PMN-PT films grown at 600 degrees C exhibit the epitaxial nature with a pure perovskite structure. The PMN-PT films exhibit a high dielectric constant of about 1991 and a low dissipation factor of 0.04 at a frequency of 10 kHz. A good polarization versus electric field hysteresis characteristic with remanent polarization of 12.5 mC/cm(2) and a coercive field of 30 kV/cm was obtained on the 800-nm thick PMN-PT films. The presence of a pyrochlore phase in the films has a critical influence on the dielectric and the ferroelectric properties. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3548534] All rights reserved.