Properties of Nb-doped lead scandium niobate titanate thin films prepared by a sol-gel method

Lead scandium niobate titanate (Pb[Sc1/2Nb1/2)(0.57)Ti-0.43]O-3) thin films with 0.5 mol% Nb doping were prepared by a sol-gel method. Films annealed at temperatures greater than 600 degrees C crystallized into a single phase perovskite structure. The films were transparent and crack-free with uniform thickness and an average grain size of 1.1 mu m The dielectric constant and dissipation factor measured at 1 kHz for a film annealed at 700 degrees C were 1370 and 0.022, respectively. Ferroelectricity was confirmed by the presence of hysteresis loops, with a remanent polarization of 20 mu C/cm(2) and coercive field of 35 kV/cm. The piezoelectric coefficient (d(33)) of a poled film was 98 pm/V. Dielectric, ferroelectric, and piezoelectric properties of the films were enhanced through annealing and poling after deposition of the top gold electrode. (C) 1999 Elsevier Science B.V. All rights reserved.