Characterization of the piezoelectric properties of Pb0.98Ba0.02(Mg1/3Nb2/3)O3-PbTiO3 epitaxial thin films

Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) (70/30) thin filins were deposited by Pulsed laser deposition using two growth strategies: adsorption controlled deposition from lead-rich targets (similar to 25-30mass%) and lower-temperature deposition (T-d <= 600 degrees C) from targets containing a small amount of excess lead oxide (<= 3 mass %). The substrates used were (001) SrRuO3/LaAlO3. Typical remanent polarization values ranged between 12 and 14 mu C/cm(2) for these films. The longitudinal piezoelectric coefficient (d(33,f)) was measured using in situ four-circle X-ray diffraction, and the transverse coefficient (d(31),(f) or e(31,f))was measured using the wafer flexure method. d(33,f) and e(31,f) coefficients of similar to 300-350 pm/V and similar to -11 C/m(2) were calculated, respectively. In general, the piezoelectric coefficients and aging rates were strongly asymmetric, suggesting the presence of a polarization bias. The large, extremely stable piezoelectric response that results from poling parallel to the preferred polarization direction is attractive for miniaturized sensors and actuators.