Dielectric constant evaluation of dielectric powders by complex impedance analysis with model of RC-RC parallel circuits connected in series

A new evaluation method for the high dielectric constants of SrTiO3 and BaTiO3 powders has been developed using the complex impedance measurement analyzed by a model of RC-RC parallel circuits that are individually connected in series. The model properly represented the various dispersions of the powders in the slurry specimens. This evaluation method was experimentally examined using SrTiO3 powder with an average particle size of 300 nm and BaTiO3 powder, 500 nm. The dielectric constants were obtained by (1) fitting the complex impedance of the models of RC parallel circuits connected in series to the measured complex impedance of the slurry specimens and (2) applying simultaneous equations to calculate each parameter of the model of RC-RC parallel circuits connected in series. The obtained dielectric constants of the SrTiO3 and BaTiO3 powders were estimated to be 232 3 and 2,610 190, respectively. They were in good agreement with the dielectric constant of the paraelectric SrTiO3 single crystal and the average value of the ferroelectric BaTiO3 single crystal.