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)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 (epsilon'(max) = 33,000 at T-max = 40degreesC and P-r = 18 muC/cm(2) at room temperature) for the stoichiometric PMN-PT ceramics sintered at 1050degreesC. 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 epsilon'(max) = 10,000 and P-r = 11 muC/cm(2) only. (C) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.