Electrical transport properties and conduction mechanisms of semiconducting iron bismuth glasses

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• 作者：M.G. Moustafa ; ^{mgmoustafa@azhar.edu.eg" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Iron bismuth glasses ; DC conductivity ; SPH ; VRH ; Schnakenberg's polaron hopping
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：15 November 2016
• 年：2016
• 卷：42
• 期：15
• 页码：17723-17730
• 全文大小：882 K

文摘

DCelectrical conductivity measurements were carried out on iron bismuth glasses with the nominal composition (100&ndash;x)Bi₂O₃&ndash;x Fe₂O₃(where x=15, 25, 35and 45 mol%) in an attempt to understand the nature of the conduction mechanism governing the DC electrical conductivity and the effect of addition of Fe₂O₃ on electrical properties in these glasses. The investigated glasses were prepared by a normal melt quenching technique. X-ray diffraction (XRD) patterns confirmed the amorphous nature of the present glasses. DC conductivity measurements showed an enhancement in conductivity by increasing Fe₂O₃ concentration. The change in activation energy of DC conductivity with temperature reveals the change in conduction mode from small polaron hopping (SPH) at high temperatures (T>θ_D/2) to variable range hopping (VRH) at low temperatures (T<θ_D/2). The conductivity results were analyzed in terms of different theoretical models to determine the possible conduction mechanism. The analysis showed that the conductivity data are consistent with Mott's nearest-neighbor SPH model. However, both Mott VRH and Greaves VRH models are suitable to explain the data. Further, Schnakenberg's polaron hopping model is also consistent with the temperature dependence of the activation energy, but the different model parameters, for example, hopping energy and disorder energy determined from the best fits were found not to be in accordance with the prediction of the SPH model.