Dielectric properties of multiple-octahedral ceramic system Pb[(〈Mg,Zn〉1/3Nb2/3)0.8Ti0.2]O3 with Ta substitutions for Nb

A fixed fraction (20 mol%) of PbTiO3 was introduced into Pb[(Mg,Zn)1/3Nb2/3]O3 with systematic substitutions of Nb by Ta. Powders were prepared by two-stage reactions with repeated calcination to improve perovskite formation. Developed structures in the calcined powders were determined by X-ray diffraction. The low-frequency dielectric constant and loss values of the ceramics were measured. Dielectric constant spectra were further analyzed to investigate the diffuseness modes. Internal microstructures were examined using a scanning electron microscope.