Influence of Excess PbO Additions on {111} Single‐Crystal Growth of Pb(Mg 1/3 Nb 2/3 )O ₃ –35 mol% PbTiO ₃ by Seeded Polycrystal Conversion

The influence of additions of excess PbO to Pb(Mg 1/3 Nb 2/3 )O 3 –35 mol% PbTiO 3 (PMN–35PT) on {111} single‐crystal growth by seeded polycrystal conversion was studied in the range of 0–5 vol% PbO. PbO volatilization and hence weight loss during annealing was controlled effectively by a double‐crucible type of arrangement. PbO additions increased boundary mobility significantly in PMN–35PT, thus facilitating single‐crystal growth by seeded polycrystal conversion (SPC). This is attributed to the formation of a boundary wetting PbO‐based liquid phase. The growth process occurs very rapidly initially, after which it slows down. This is presumably due to both a decrease in the driving force for boundary migration because of an increase in matrix grain size, and a transition to lower mobility facets. It is also shown that for a given annealing time, the size of the grown crystal scales with the lateral dimensions of the seed crystal.