Seeding effects on the mechanochemical synthesis of 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3

A systematic investigation of the seeding effects on the mechanochemical synthesis of lead magnesium niobate lead titanate 0.9Pb(Mg1/3Nb2/3)O-3-0.1PbTiO(3) (PMN-10PT), one of the most studied relaxor-ferroelectric material for electrocaloric applications, is reported. The perovskite crystallisation process was followed by X-ray diffraction using the Rietveld refinement method and transmission electron microscopy. Compared to the mixed oxides case which requires 143 h of high-energy milling, the milling time needed to obtain a phase-pure PMN-10PT perovskite using PT seeds is reduced almost twice. The presence of PT seeds leads to faster transitions from the amorphous to pyrochlore and to perovskite phases compared to the mixed-oxides case. A sintering study demonstrates, for the first time, that a second, metastable, pyrochlore phase is taking part in the processes of perovskite formation. The PMN-10PT ceramic prepared from the PT-seeded powder exhibits electrocaloric properties comparable to reported values for PMN-10 PT prepared from oxides.