Ceramics-Silikáty 59 (2) 158-163 (2015)

PHYSICAL AND ELECTRICAL PROPERTIES ENHANCEMENT OF RARE-EARTH DOPED-POTASSIUM SODIUM NIOBATE (KNN): A REVIEW

Alkaline niobate mainly potassium sodium niobate, (K_xNa_1-x) NbO₃ (abreviated as KNN) has long attracted attention as piezoelectric materials as its high Curie temperature (T_c) and piezoelectric properties. The volatility of alkaline element (K, Na) is, however detrimental to the stoichiometry of KNN, contributing to the failure to achieve high-density structure and lead to the formation of intrinsic defects. By partially doping of several rare-earth elements, the inherent defects could be improved significantly. Therefore, considerable attempts have been made to develop doped-KNN based ceramic materials with high electrical properties. In this paper, these research activities are reviewed, including dopants type and doping role in KNN perovskite structure.

Keywords: Potassium sodium niobate, Piezoelectric, Volatility, Intrinsic defects, Rare earths