Influence of MnO2 Doping on the Dielectric and Piezoelectric Properties and the Domain Structure in (K0.5Na0.5)NbO3 Single Crystals
Abstract:MnO2-doped (K0.5Na0.5)NbO3 (KNN) single crystals were grown by high-temperature solution method using K2CO3–Na2CO3 eutectic composition as flux. The effect of the manganese dopant on the dielectric, piezoelectric properties and the domain structure was investigated. The MnO2-doped KNN crystals were found to exhibit higher piezoelectric coefficient d33 and dielectric permittivity r when compared with pure KNN crystal, being on the order of 270 pC/N and 730, respectively, for manganese-doped level at 0.5 mol%, with slightly reduced orthorhombic to tetragonal phase transition TO—T, and Curie temperature TC, being on the order of 193° and 416°C, respectively. The domain size of -oriented KNN–Mn crystal was found to be on the order of 5–13 m at room temperature, smaller than that of the domain size observed in the pure KNN crystal (20–30 m). The thermal depoling experiments were performed on the -poled KNN–Mn crystals, where the partial depolarization was found to occur at temperatures above 200°C, due to the phase transformation.
Document Type: Research Article
Affiliations: 1: Electronic Materials Research Laboratory, Key Laboratory of Education Ministry, Xi'an Jiaotong University, Xi'an 710049, China 2: Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, U.S.A.
Publication date: April 1, 2010