Grain Growth Control and Solid‐State Crystal Growth by Li 2 O/PbO Addition and Dislocation Introduction in the PMN–35PT System

Grain growth behavior and solid‐state single crystal growth (SSCG) in the Pb(Mg 1/3 Nb 2/3 )O 3 –35 mol% PbTiO 3 (PMN–35PT) system have been investigated with varying Li 2 O/PbO ratios. The effect of dislocation density on crystal growth has also been studied. For SSCG, a BaTiO 3 single‐crystal seed was embedded in a polycrystalline PMN–PT matrix. During annealing, a PMN–PT single crystal grew from the seed at the cost of the small matrix grains. Addition of Li 2 O dopant first enhanced and then reduced abnormal grain growth in the matrix. In the 2 mol% Li 2 O and 6 mol% PbO excess PMN–PT samples annealed at 1200°C, considerable single‐crystal growth occurred without formation of abnormally large grains in the matrix. Increasing the dislocation density in the BaTiO 3 seed crystal resulted in enhanced growth of single crystals. These results were explained in terms of interface reaction‐controlled nucleation and growth, based on crystal growth theories.