Effects of barium substitution on perovskite formation, dielectric properties, and diffuseness characteristics of lead zinc niobate ceramics

Perovskite-phase developments in partially/fully substituted (Ba,Pb)(Zn1/3N b2/3)O-3, synthesized via B-site precursor routes, were investigated. The p yrochlore structure, present at no barium content, was immediately replaced by perovskite with a small amount (greater than or equal to 8 at.%) of bar ium substitution. Variations in the lattice parameters of the pyrochlore an d perovskite structures were studied. The weak-field radio-frequency dielec tric constants and losses of the system ceramics were examined. A highest m aximum dielectric constant of 9000 (76 degrees C, 1 MHz) was observed at 8 at.% barium substitution. The dielectric-constant spectra were analyzed fur ther in terms of diffuseness characteristics (e.g., diffuseness exponent an d degree of diffuseness). The dielectric hysteresis leaps of the ceramics w ere measured. The microstructures of the sintered ceramics also were observ ed.