Dielectric and piezoelectric properties of (x)Pb(Mg1/3Nb2/3)O3–(1−x)Pb(Zr1/2Ti1/2)O3 thin films prepared by the sol–gel method

The dielectric and piezoelectric properties of sol–gel derived (x)Pb(Mg1/3Nb2/3)O3–(1−x)Pb(Zr1/2Ti1/2)O3[(x)PMN–(1−x)PZT] thin films were investigated as a function of PMN content (x=0–1). For all compositions in the (x)PMN–(1−x)PZT thin films, a well-developed perovskite phase with (111) preferred orientation was obtained at the annealing temperature range of 700–800 °C. With increasing PMN content, the dielectric constant increased, while the remnant polarization and coercive field decreased. The enhanced dielectric properties were shown in the region of x=0.2. At this composition, the dielectric constant and remnant polarization were 1750 and 12.75 μC/cm2, respectively, which indicate that the morphotropic phase boundary (MPB) exists near the composition of x=0.2. The transverse piezoelectric coefficient (d31) showed a maximum value of −84 pC/N at x=0.2. These results confirmed that enhancement of the dielectric constant and remnant polarization improved the piezoelectric properties at the MPB.