Nucleation of Ferroelectric Domains under the Influence of Electric Fields in Al-doped KNbO_3 Single Crystals

摘要

Interesting photographic evidence for domain wall nucleation has been found on the naturally grown surfaces of KNbO_3 single crystals. For this case domain nucleated under the influence of an applied electric field. This can be studied in the case of Al_2O_3 doped KNbO_3 single crystals. When doping concentration of Al_2O_3 is increased, maximum number of domain lines disappeared at very low electric field. By applying more electric field, more stress produce in the crystal surface. The present work has led to the concept of nucleation of a domain wall and the formation of linear impurity structures can be clearly understood in terms of the dipolar impurities.