Effects of annealing temperature on structure and electrical properties of sol-gel derived 0.65PMN-0.35PT thin film

0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (0.65PMN-0.35PT) thin films were deposited on Pt/Ti/SiO2/Si substrates annealed from 550 to 700 °C using sol-gel process. The effects of annealing temperature on microstructure, insulating, ferroelectric and dielectric properties were characterized. The result reveals that 0.65PMN-0.35PT thin films possess a polycrystalline structure, matching well with the perovskite phase despite the existence of a slight pyrochlore phase. The film samples annealed at all temperatures exhibit relatively dense surfaces without any large voids and the grain size increases generally with the increase of the annealing temperature. Meanwhile, pyrochlore phase is considerably generated because of the deformation of perovskite phase caused by volatilization of Pb at an excessive high-temperature. The film annealed at 650 °C exhibits superior ferroelectricity with a remanent polarization (Pr) value of 13.31 μC/cm2, dielectric constant (εr) of 1692 and relatively low dielectric loss (tanδ) of 0.122 at 104 Hz due to the relatively homogeneous large grain size of 130 nm and low leakage current of approximately 10-6 A/cm2.