Phase formation and dielectric properties of 0.90Pb(Mg 1/3Nb 2/3)O 3–0.10PbTiO 3 ceramics prepared by a new sol–gel method

Abstract

Ceramics of lead magnesium niobate–lead titanate solid solution, 0.90Pb(Mg 1/3Nb 2/3)O 3–0.10PbTiO 3 (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 ( ε max′=33,000 at T max=40 °C and P r=18 μC/cm 2 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 ε max′=10,000 and P r=11 μC/cm 2 only.