Polyethylene Glycol-Based New Solution Route to Relaxor Ferroelectric 0.65Pb(Mg_1/3Nb_2/ ₃)O₃−0.35PbTiO₃

Abstract

A new soft chemistry route has been developed for the synthesis of relaxor ferroelectric lead magnesium niobate−lead titanate solid solution (0.65PMN−0.35PT). The method uses a poly(ethylene glycol) (PEG) and methanol mixture as solvent. It allows reactions to be performed at room temperature without using an excess amount of the lead starting material to compensate for lead oxide loss during ceramic sintering as is usually the case in conventional synthesis. The effect of using a triol molecule, 1,1,1-tris(hydroxymethyl)ethane (THOME), which serves as a complexing agent in binding together the metal ions in the precursor solution, has also been studied. Pure perovskite phase was obtained in ceramics sintered at a relatively low temperature of 1040 °C as compared to 1250 °C in solid-state reactions. A high dielectric constant (at 1 kHz) of above 5000 is found at room temperature and the value reaches ∼27 000 at the Curie temperature. Ferroelectric hysteresis loops are displayed on a ceramic with an average grain size of 2 μm, giving rise to a remnant polarization (Pr) of 21 μC/cm2 and a coercive field (Ec) of ∼7.5 kV/cm.