Measurement and analysis of time-domain electric field relaxation: The vitreous ionic conductor 0.4 Ca(NO3)2–0.6 KNO3

We have measured the electric modulus $\mathrm{M(t)}$ of the ionic conductor ${\mathrm{0.4\hspace{0.17em}Ca(NO}}_{\mathrm{3}}{\mathrm{)}}_{\mathrm{2}}{\mathrm{–0.6\hspace{0.17em}KNO}}_{\mathrm{3}}$ (CKN) by recording the electric field relaxation $\mathrm{E(t)}$ under the constraints of a constant displacement $D_0.$ The vitreous material CKN is studied in its glassy state for temperatures $\text{240\hspace{0.17em}}\mathrm{K}\text{⩽T⩽330\hspace{0.17em}}\mathrm{K}$ and for times ${\text{7×10}}^{\text{−3}}\hspace{0.17em}\mathrm{s}{\text{⩽t⩽3×10}}^5\hspace{0.17em}\mathrm{s}.$ In this range the dc conductivity varies from ${\text{3×10}}^{\text{−11}}$ to ${\text{5×10}}^{\text{−17}}\hspace{0.17em}\mathrm{S/cm}$ according to Arrhenius behavior. We show that the time dependent resistivity $\mathrm{\rho (t),}$ instead of the conductivity $\mathrm{\sigma (t),}$ is an appropriate quantity for assessing the time dependent and steady state effects of ionic diffusivity on the basis of experimental modulus data $\mathrm{M(t)}$ recorded in the time domain. Even substantial electrode polarization is not critical with regard to this data analysis.