Dielectric properties of Ta2O5–ZrO2 polycrystalline ceramics

Abstract

The dielectric properties of ${\mathrm{(Ta}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{5}}{\mathrm{)}}_{\text{1−x}}{\mathrm{(ZrO}}_{\mathrm{2}}{\mathrm{)}}_x$ polycrystalline ceramics at 1 MHz and temperatures between 0 and 100 °C are reported for $\text{0.0<x<0.25.}$ The dielectric constant is moderately enhanced in the solid solution as a function of Zr content, and there is a significant decrease in the temperature coefficient of the dielectric constant (TCK). The annealing temperature of the ceramics is found to have a dramatic effect on TCK, associated with the appearance of the low temperature form of tantalum oxide at intermediate Zr concentrations, and ${\mathrm{Ta}}_{\mathrm{4}}{\mathrm{Zr}}_{\mathrm{11}}{\mathrm{O}}_{\mathrm{32}}$ at high Zr concentrations: a bulk ceramic consisting of a mixture of the latter two phases was found to display a dielectric constant of $\text{≈50}$ and a temperature coefficient of $\text{≈−40\hspace{0.17em}}\mathrm{ppm/°C}.$