Insight on the weak hopping conduction produced by titanium ions in the lead borate glassy system

Abstract DC conductivity investigation was conducted on the lead borate glass system of the composition (75–x) PbO–25B2O3–xTiO2, x = 15, 20, 25, and 30 mol %, to access the potential conduction mechanism controlling the conductivity data of the present glass system. The melt quenching method was utilized to prepare this glassy system. The amorphous nature of the present glass system was asserted by SEM. The theoretical density of the present glass system was larger than the corresponding measured one, affirming the completely amorphous essence of these glasses. The conductivity of these glasses slightly increased with TiO2 additions. Strikingly, when the Pb-ions become attached to Ti-ions in the glass matrix they minimize their hopping motions, leading to the occurrence of the weak hopping process in these glasses. Accordingly, PbO played a vital role in revealing the weak hopping without needing low-temperature measurements close to absolute temperature. The conduction mechanism in these glasses was determined by different models arising from the typical hopping of charge carriers. The polarons hopping occurred in the non-adiabatic process. The values of different parameters, such as small polaron coupling and hopping carrier mobility, asserted the occurrence of the weak hopping process in these glasses. The Greaves VRH model was proper to elucidate the conductivity data of these glasses.