Preparation and dielectric properties by sol–gel derived PMN-PT powder and ceramic

A relaxor ferroelectric material, 0.85Pb(Mg1/3Nb2/3)O3-0.15PbTiO3 with a pyrochlore-free phase, was prepared by using sol–gel method. The metal alkoxide Nb(OC2H5)5 and Mg(OC2H5)2 are substituted by Nb(OH)5 and Mg(NO3)2. During the processing the gel first converted to pyrochlore phase at a calcination temperature of 500°C followed by the formation of pure perovskite phase at 1100°C. The grain size and the dielectric constant increased with an increase in the sintering temperature. The chemical composition analysis shows starting material shift to a higher PT-content (PT∼17%) for the final material.