Electrical conduction in 70V2O5·30TeO2 (mol%) pelletized glasses annealed in an H2 gas atmosphere

• Published in: Journal of non-crystalline solids 2019-06, Vol.513, p.1-8
• Main Author: Mori, Hidetsugu
• Format: Article
• Language: English
• Subjects: Annealing; Greaves' variable-range hopping; H2 atmosphere; Mott's variable-range hopping; Small polaron hopping; Tellurite glass; Vanadate glass
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2019.02.011

The direct-current electrical conductivities (σ) of 70V2O5∙30TeO2 (mol%) pelletized glasses annealed in an H2 gas atmosphere at 473 K were determined in the temperature (T) range of 322–473 K. Based on the log(σT)–T−1 relation in the considered temperature range, the electrical conduction is discussed in detail. The conduction of each glass sample at high temperatures (T > ~460 K) was attributed to nonadiabatic small polaron hopping. At T < ~353 K, the slopes of the curves were the smallest. The smallest slopes at temperatures below ~353 K are discussed based on the Mott's and Greaves' variable-range hopping (VRH) conduction models. The tunneling factors α and densities of states at the Fermi level N(EF) estimated using the Mott's VRH model confirmed that this model was not suitable. On the other hand, the α and N(EF) values estimated by the Greaves' VRH model indicated that the conduction was attributed to the Greaves VRH. The values of WD (0.0765 ± 0.0006 to 0.108 ± 0.0006 eV) calculated using the Greaves' model were on the same order as those of the reported vanadate binary glasses. These parameters demonstrated that the Greaves' VRH model was applicable for the considered glasses and could be used to explain the conductivity data at temperatures below ~354 K. •The DC electrical conductivities of pelletized 70V2O5∙30TeO2 (mol%) glasses annealed in H2 gas were determined at 322–473 K•The electrical conductions in the glasses are discussed based on the conductivity–temperature relations•The conduction at high temperatures (above ~460 K) was attributed to nonadiabatic small polaron hopping•The Greaves’ variable-range hopping model was applicable for the glasses below ~354 K