Seeding of perovskite lead magnesium niobate crystallization from Pb-Mg-Nb-EDTA gels

The addition of BaTiO3 seed particles (50 nm in diameter) to a Pb-Mg-Nb-EDT A solution (where EDTA represents ethylenediamine tetraacetic acid) reduces the formation temperature from 700 degrees C to 600 degrees C during combu stion synthesis, because of epitaxial effects. The lower perovskite formati on temperature eliminates the formation of pyrochlore at the surface of the precursor bed and allows for the direct crystallization of similar to 98% perovskite lead magnesium niobate (PMN) during combustion synthesis. Increa sing the nucleation density of the seed particles in the seeded precursor d ecreases the precursor volume that is associated with each perovskite nucle us and, thus, reduces the PMN particle size from 1 mu m to 0.2 mu m. The in fluence of BaTiO3 seeding is discussed in terms of the thermodynamics of pe rovskite formation, the influence of BaTiO3 seed concentration, and epitaxi al nucleation.