Chakraborty, S and Sadhukhan, M and Modak, D K and Som, K K and Maiti, Himadri Sekhar and Chaudhuri, B K (1995) Study of the ac conductivity of BaTiO3-doped V2O5-Bi2O3 glasses using longs overlapping large-polaron tunneling model. Philosophical Magazine B-Physics of Condensed Matter Statistical Mechanics Electronic Optical and Magnetic Properties , 71 (6). pp. 1125-1135. ISSN 1364-2812

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In the present paper we report the results of a study of the frequency-dependent a.c. conductivity sigma(a.c.) of the BaTiO3-doped (5-40wt%) 90V(2)O(5)-10Bi(2)O(3) (VB) glassy semiconductor system over a wide frequency range (500-10000Hz) and wide temperature range (80-450 K). The semiconducting behaviour of these glasses is due to the presence of V4+ and V5+ valence states. While the correlated barrier hopping of bipolarons is responsible for the a.c. conductivity in the undoped glasses, Long's overlapping large polaron tunnelling mechanism is found to be valid for all these BaTiO3-doped VB glass compositions. Such a change in conduction mechanism is not usually observed in transition-metal oxide glasses and it is due to the change in network. structure of the VB glass arising from the addition of BaTiO3. The doped glasses, however, show phase separation even in the glassy phase in contrast with the pure VB glass. The d.c. conductivity of doped glasses showed a non-adiabatic conduction mechanism in contrast with the cases of V2O5-Bi2O3 and many other vanadate glasses with the usual glass formers, where an adiabatic hopping conduction mechanism is applicable. The a.c. conductivity follows a power law (namely sigma(a.c.) (alpha)omega(5) with s < 1) for both doped and undoped systems. The model parameters obtained from a least-squares fitting of the experimental a.c. conductivity data also agree quite well with those obtained from other methods.

Item Type: Article
Subjects: Glass
Depositing User: Bidhan Chaudhuri
Date Deposited: 21 Aug 2012 10:33
Last Modified: 23 Mar 2016 12:35

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