Effect of mixed transition-metal ions in glasses. Part III: The P2O5–V2O5–MnO system

DC conductivity of rare earth ions doped vanado-tellurite glasses

“…The W values for VLT glasses lies between 0.482 eV and 0.500 eV, whereas for VCT glasses they are in the range 0.455-0.501 eV. The sizes of the high temperature activation energy are in agreement with the reported literature values for tellurite glasses doped with different rare earth ions and other similar glass systems [18,[26][27][28]. The activation energy increased with the increase in La 2 O and CeO 2 in the present sets of glasses.…”

“…Table 2 it can be seen that the pre-exponential factor r 0 depends on TMI content present in the glass. This confirms the conduction mechanism to be of non-adiabatic type in these glasses [28]. Non-adiabatic hopping conduction can also be established from the plot of conductivity, r, at 450 K vs. W, (Fig.…”

“…Non-adiabatic hopping conduction can also be established from the plot of conductivity, r, at 450 K vs. W, (Fig. 4), wherein the slope is not equivalent to theoretical slope for the adiabatic conduction mechanism, i.e., slope = À1/2.303k B T [28]. If the temperature is correctly estimated from such a slope then the conduction mechanism is termed as adiabatic otherwise non-adiabatic.…”

“…The value of a was taken from the literature quoted for TMI doped glasses (a = 20 nm À1 ) [28]. From the table it can be noted that J for all the glasses satisfies the condition for non-adiabatic conduction given in Eq.…”

Electronic transport properties of mixed transition metal ions doped borophosphate glasses

“…However, incorporation of few boron atoms into phosphate glass network has been shown to increase chemical durability of the phosphate glasses [8]. The electrical conductivity studies in phosphate and borate glasses doped with different single and mixed TMI have been studied by some authors [1,[4][5][6][9][10][11]. Various theoretical models such as Mott's small polaron hopping (SPH), variable range hopping (VRH) [12,13] and Greaves VRH models [14] have been used to explain temperature dependence of conductivity in these glasses.…”