Melt growth and characterization of PbBr 2 single crystals

PbBr ₂ single crystals were grown by a vertical Bridgman method. The objective of this work is to examine the following two: (i) how the crystal quality is influenced by purification, (ii) how the crystal quality is influenced by growth rate. The following results were obtained. (1) The crystals grown from the materials of 99.99% and 99.999% purity were not transparent if they were not purified. On the other hand, a transparent crystal was obtained even from the material of 99.99% purity when it was refined by directional freezing as well as vacuum distillation. (2) It was found that very slow growth rate was needed to grow transparent crystals.