Correlation between thermal properties, growth parameters and low segregation coefficient in (K, Na)NbO3-based growth by Bridgman-Stockbarger route

In order to achieve optimized growth conditions to reduce the compositional segregation in (K,Na)NbO3-based crystals produced by the vertical Bridgman-Stockbarger (VB-S) method, both a complete previous analysis of the thermal properties of the precursor oxides and a suitable choice of the dimensions of the crucible were made based on theoretical models proposed in the literature. By following this approach, chemical analysis of the asgrown crystals revealed very small effective segregation coefficients in the radial and longitudinal directions of the as-grown crystals. The obtained results revealed that is possible to grow single crystals by VB-S even for incongruent compounds, through a suitable establishment of the growth parameters adjusted according to the thermal properties of the piezoelectric oxide and the relative dimensions of the crucible.