Critical issues in single crystal growth of PMN-PT by seeded polycrystal conversion

Pb(Mg1/3Nb2/3)O-3-35mol%PbTiO3, [PMN-35PT] single crystals have been produced via the Seeded Polycrystal Conversion process by embedding a seed crystal in a polycrystalline ceramic matrix, and inducing the single crystal boundary to migrate at the expense of the smaller matrix grains. Maintaining single crystal growth until full conversion of the polycrystal can only be achieved with an improved fundamental understanding of the factors that influence the migrating boundary. The present work addresses, in particular, the roles of liquid phase content and chemistry, sintering atmosphere, and defects such as twin boundaries. Characterization of the liquid film thickness and composition at key interfaces during the firing/growth cycle are discussed. Implications regarding the effect of PbO content on single crystal growth mechanisms are also presented.