Flux growth and characterization of the relaxor-based Pb[(Zn1/3Nb2/3)1−xTix]O3 [PZNT] piezocrystals

Relaxor ferroelectric-based single crystals (1−x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 [PZNT] (x=0 and 0.09) were grown from high temperature solutions, using PbO or PbO/δB2O3 as flux. The optimum flux compositions and concentrations were found to be 50 wt.% PbO and (49 wt.% PbO+1 wt.% B2O3). It has been shown that addition of up to 1 wt.% B2O3 can stabilize the perovskite phase and improve the effectiveness of the flux. The optimum thermal profile consists of a soaking temperature at 1100°C and a gradually increasing cooling rate from 2 to 5°C min−1. The spontaneous nucleation process could be significantly modified by top-seeding technique. The crystal morphology was studied and related to a layer growth mechanism controlled by two-dimensional growth, and to the formation of pyramidal growth sectors. The phase analysis, the morphotropic domain structures and phase transitions, and the dielectric properties of the grown PZNT crystals were characterized by X-ray powder diffraction, polarized light microscopy and dielectric spectroscopy.