Understanding the electrode polarization in bismuth zinc vanadate semiconducting glasses from dielectric spectroscopy: A new insight on electrode polarization effect

Abstract The dielectric spectroscopy of 50V2O5. x Bi2 O3. (50-x) ZnO glass system have been investigated in the light of different theoretical models already available in literature. An empirical expression has been deducted by modifying Cole-Cole model for the complex dielectric constant ( e * ), e * = e ∞ + e s − e ∞ 1 + ( i ω τ e ″ ) m + σ D C i ω e 0 + 2 e 0 K 1 L ( σ D C e 0 e ∞ ) 2 ω 2 K 1 2 L 2 + ( ρ σ D C e 0 e ∞ ) 2 with the condition K 1 L ≫ ρ . This modified model explains the experimentally observed variation of both e ′ and e ″ for all the glass compositions under investigation in frequency range of 4 Hz to 1.2 MHz and temperature ranging from 333 K to 533 K. The electrode polarization takes place via space charge mechanism. The relation between dielectric constant at high frequencies ( e ∞ ), modulus relaxation time ( τ M ″ ) and dc conductivity ( σ D C ) holds good for studied glass compositions.