Thermal diffusivity measurements on ternary Ge-Te-Tl glasses using Photo-thermal Deflection method: Effect of thallium addition

Rahman, Mohammad Mahbubur and Rukmani, K and Sekhar, Rajam and Asokan, S (2012) Thermal diffusivity measurements on ternary Ge-Te-Tl glasses using Photo-thermal Deflection method: Effect of thallium addition. In: JOURNAL OF NON-CRYSTALLINE SOLIDS, 358 (12-13). pp. 1501-1505.

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Abstract

Photo-thermal Deflection (PTD) technique is used to investigate the thermal diffusivity (alpha) of Ge17Te83 - xTlx (0 <= x <= 13) glasses as a function of composition. The thermal diffusivity of these glasses is found to lie in the range 0.020 to 0.048 cm(2)/s, which is consistent with the memory type of electrical switching exhibited by these samples. Further, it is found that alpha shows an initial increase with Tl addition, followed by a decrease. The observed composition dependence of thermal diffusivity has been understood on the basis that the thallium atoms are incorporated as a covalent species for lower values of x, increasing the network rigidity; however, they enter as ionic species for higher x values, fragmenting the network. The initial increase in a is due to the increasing network rigidity and the subsequent decrease is because of the fragmentation of the network. Also, there is a strong correlation between the composition dependence of switching voltages observed earlier and the variation with composition of electrical resistivity and thermal diffusivity of Ge17Te83 - xTlx glasses obtained in the present study. (C) 2012 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Additional Information:	Copyright for this article belongs to Elsevier Science
Keywords:	Chalcogenides; Thallium addition; Thermal diffusivity
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation and Applied Physics (Formally ISU)
Date Deposited:	06 Sep 2012 12:46
Last Modified:	06 Sep 2012 12:46
URI:	http://eprints.iisc.ernet.in/id/eprint/45005

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