PLZT Anti-ferroelectric Materials

In this paper, using the traditional solid-phase reaction, we got several series of anti-ferroelectric materials. First, we got anti-ferroelectric La-doped lead zirconate titanate (PLZT), research the properties of the system as a function of La³⁺ content and Zr/Ti. Then, PLZT was prepared as basic material. It was doped with ferric oxide and zinc oxide, research the properties of the system as a function of ferric oxide and zinc oxide. At the last, PLZT was also prepared as basic material, using the traditional adding methods to study the low-temperature sintering, it was doped with lithium oxide and bismuth oxide.Study found that, in PLZT (0.07≤x≤0.18), the phase of material from ferroelectric triangle phase (x≤0.09) turn into the antiferroelectric phase (0.11≤x≤0.14) and then nearly cubic phase (x≤0.15) with the increment in La³⁺ content in room temperature. La³⁺ enhanced anti-ferroelectricity stability, this system induced-electric field AFE-FE change presents the characteristics of dispersion phase change, "narrow, oblique" type double hysteresis loops reflects PLZT multiple complex compounds the ferroelectric ceramics internal chemical compositions of the nanometer scale heterogeneity.The adding of ferric oxide and zinc oxide, obviously reduced the relative dielectric constant and dielectric loss, and effectively improved the Curie temperature, weakened the dispersion degree of phase transition. But with the amount of doping is too much, the dielectric performance of materials would be worse.A moderate amount of lithium oxide and bismuth oxide can significantly reduce the sintering temperature and improve the dielectric performance of the ceramics at low temperature. But when lithium oxide and bismuth oxide were excessive, the porosity of ceramics increased, the density of ceramic reduced, and grain uniformity becomes poor. Lithium oxide was doped alonely, most gathered in grain boundary, when lithium oxide and bismuth oxide were co-doped, most into lattice, reducing the sintering temperature effectly. When bismuth oxide content is 0.3 mol %, lithium oxide content is0.7mol %, it can make the sintering temperature of PLZT from 1250℃down to 1190℃, and with high comprehensive performance.