In Situ Observation of the Surface of Barium Nitrate Crystals Growing in Supersaturated Solution

Abstract

The behaviour of steps on the (111) face of growing barium nitrate crystals were observed, using a reflection-type Nomalsky differential microscope. Several growth spirals always existed on the surface. Some of them originated form points on the surface to which small crystallites accidentally adhered from the solution. The velocity of the steps changed according to their mutual interference, the addition of impurity (Na⁺) and the existence of microscopic roughness on the surface. There were small crystal fragments adhering to the mechanically damaged surface of the crystal. These fragments were covered by new layers. In addition, macrosteps were easily formed on the damaged surface, and overhang of the steps and inclusion of mother solution were successively formed.