Perovskite formation, dielectric and ferroelectric properties of PbZrO3–Pb(Ni1/3Nb2/3)O3ceramics via a columbite precursor synthetic route

Perovskite structures in the PZ–PNN system with formula (1−x)PbZrO3–xPb(Ni1/3Nb2/3)O3 with x = 0.0–0.5 are synthesized via the columbite precursor technique. The formation of the perovskite phase in the calcined powders has been investigated as a function of calcination conditions by using thermogravimetric and differential thermal analysis (TG-DTA) and x-ray diffraction (XRD) techniques. The complete solid solutions of the perovskite phase of PZ–PNN ceramics were obtained over a wide compositional range. It was observed that for the binary system (1−x)PbZrO3–xPb(Ni1/3Nb2/3)O3, the change in the calcination temperature is approximately linear with respect to the PNN content in the range x = 0.0–0.5. With increasing x, the calcination temperature shifts forward to high temperatures. It is seen that optimization of the calcination conditions can lead to a 100% yield of PZ–PNN in a pseudo-cubic phase. The P–E hysteresis loop measurements demonstrated that the ferroelectric properties of the ceramics in the PZ–PNN system changed gradually from normal ferroelectric behavior to relaxor ferroelectric behavior with increasing PNN concentration. In addition, the squareness of the hysteresis loop (Rsq) decreased quasi-linearly as the molar fraction of PNN increased. The maximum spontaneous polarization (Ps) and remanent polarization (Pr) for the x = 0.1 composition were 31.6 µC cm−2 and 27.8 µC cm−2, respectively. These results clearly show the significance of PNN in controlling the electrical responses of the PZ–PNN system.