Effect of sintering temperature on the phase transition and dielectrical response in the relaxor-ferroelectric-system 0.5PZN–0.5PZT

Abstract

Relaxor ferroelectrics of 0.5Pb(Zn1∕3Nb2∕3)O3–0.5Pb(Zr0.47Ti0.53)O3 (0.5PZN–0.5PZT) near the morphotropic phase boundary (MPB) were prepared using the conventional oxide mixing method. The influence of sintering temperature on the phase transition and dielectrical response in the relaxor-ferroelectric-system 0.5PZN–0.5PZT has been investigated. X-ray diffraction analysis indicated that the phase of the material changed from an initially rhombohedral structure to a MPB structure and then a tetragonal structure when the sintering temperature is increased from 900to1250°C. The corresponding grain size is enlarged from 1.1μm for predominantly rhombohedral to 2.5μm for more than 60% tetragonal, which obeys the common grain-growth law. The dielectric studies revealed that the indicator of the degree of diffuseness γ decreased with the increase of the sintering temperature from 900to1150°C, indicating that the dielectric relaxor behavior was weakened, while at high sintering temperature above 1250°C, γ increased subsequently, which was attributed to the Pb vacancy due to the formation of a pyrochlore phase. Raman analysis on the B-site cation order correlates well with the dielectric measurement results.