Growth, mechanical property and domains of lead potassium niobate single crsytal

Lead potassium niobate (Pb₂KNb₅O₁₅, PKN) single crystal with tungsten bronze has been successfully grown by Bridgman method through spontaneous nucleation. Under the optimized growth conditions, the crystal was transparent, cracks free and inclusions free. The mechanical property was measured through the Vickers microhardness technique. The result showed that the relationship between the Vickers´ microhardness and load could be described as Hv=1.90P-0.2057GPa. Strip-shaped domains were observed in PKN crystals. The changes of the domains during the temperature increasing process indicated that the Currie temperature of PKN was in the range of 460-470°C.