Electrical conductivity and dielectric loss in doped Pb(NO3)2 single crystals

dc ionic conductivity measurements were made on single crystals of Pb(NO₃)₂ doped with monovalent Na⁺ and K⁺ in the temperature range of 100–400°C. In the extrinsic region the conductivity was found to decrease with Na⁺ having a smaller ionic size, and to increase with K⁺ with larger ionic size compared to the host Pb ion. Conductivity is attributed to the mobility of anti-Frenkel defects as in the case of PbF₂. Dielectric loss measurements were made on the Pb(NO₃)₂: K⁺ system in the frequency range of 300 Hz to 20 kHz at different temperatures. Impurity vacancy pairs of the type K⁺-(NO^-₃)_V are found to be responsible for the observed dielectric loss peaks. The maximum peak frequency is found to increase with temperature.