Growth and properties of Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 single crystals directly from melt

Pb[(Zn1/3Nb2/3)(0.91)Ti-0.09]O-3 (PZNT91/9) single crystals were grown by a modified Bridgman method directly from melt using an allomeric Pb[(Mg1/3Nb2/3)(0.69)Ti-0.3]O-3 (PMNT69/31) single crystal as a seed. X-ray diffraction (XRD) measurement confirmed that the as-grown PZNT91/9 single crystals are of pure perovskite structure. Electrical properties and thermal stabilization of PZNT91/9 crystals grown directly from melt exhibit different characters from those of PZNT91/9 crystals grown from flux, although segregation and the variation of chemical composition are not seriously confirmed by X-ray fluorescence analysis (XPS). The [0 0 1]-oriented PZNT91/9 crystals cut from the middle part of the as-grown crystal boules exhibit broad dielectric-response peaks at around 105 degrees C, accompanied by apparent frequency dispersion. The values of piezoelectric constant d(33), remnant polarization P, and induced strain are about 1800-2200pC/N, 38.8 mu C/cm(2), and 0.3%, respectively, indicating that the quality of PZNT crystals grown directly from melt can be comparable to those of PZNT91/9 single crystals grown from flux. However, further work deserves attention to improve the dielectric properties of PZNT crystals grown directly from melt. Such unusual characterizations of dielectric properties of PZNT crystals grown directly from melt are considered as correlating with defects, microinhomogeneities, and polar regions. (c) 2008 Published by Elsevier B.V.