Dielectric relaxation in Bi2O3–ZnO–Nb2O5 cubic pyrochlore

Frequency dispersion associated with dielectric relaxation phenomena in polycrystalline cubic pyrochlore with normal composition $({\mathrm{Bi}}_{\mathrm{1.5}}{\mathrm{Zn}}_{\mathrm{0.5}}{\mathrm{)(Zn}}_{\mathrm{0.5}}{\mathrm{Nb}}_{\mathrm{1.5}}{\mathrm{)O}}_{\mathrm{7}}$ is analyzed. Measurements at cryogenic temperatures and high frequencies reveal a broad distribution of relaxation times. The associated dielectric loss data can be modeled with a function convoluting the Vogel–Fulcher law and a Gaussian distribution. This function, dependent only on measuring frequency and temperature, describes exceptionally well the phenomena observed over a frequency range covering seven decades and over 300 K.