Phase formation and dielectric properties of 0.90Pb(Mg1/3Nb2/3)O3–0.10PbTiO3 ceramics prepared by a new sol–gel method

Ceramics of lead magnesium niobate–lead titanate solid solution, 0.90Pb(Mg1/3Nb2/3)O3–0.10PbTiO3 (PMN–PT), have been synthesized by a new room temperature sol–gel route, using polyethylene glycol-200 (PEG) and methanol mixture as solvent. The use of a triol molecule, 1,1,1-tris(hydroxymethyl)ethane (THOME), which is known to serve as a complexing agent used in binding together the metal ions in the precursor solution, has been shown to give good dielectric and ferroelectric properties (εmax′=33,000 at Tmax=40 °C and Pr=18 μC/cm2 at room temperature) for the stoichiometric PMN–PT ceramics sintered at 1050 °C. A 5 mol% excess of lead in the sol–gel process without THOME led to an improvement in the formation of the perovskite phase but a degradation of the dielectric properties with εmax′=10,000 and Pr=11 μC/cm2 only.