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Influence of connectivity on the rigidity of the covalently bonded (GeTe4)(100-x)(As2Se3)(x) glasses

Pumlianmunga, Pumlianmunga and Venkatesh, R and Naresh, N and Sankhla, Aryan and Gopal, ESR and Ramesh, K (2016) Influence of connectivity on the rigidity of the covalently bonded (GeTe4)(100-x)(As2Se3)(x) glasses. In: JOURNAL OF NON-CRYSTALLINE SOLIDS, 447 . pp. 178-182.

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Official URL: http://dx.doi.org/10.1016/j.jnoncrysol.2016.06.014

Abstract

Bulk (GeTe4)(100 - x)(As2Se3)(x)(0 <= x <= 60) glasses in the tie-line GeTe4-As2Se3 prepared by melt quenching method are characterized by differential scanning calorimetry (DSC), X-ray diffraction and Raman spectroscopy. In covalent network glasses, the structural network transform from a floppy to a rigid structure at an average coordination number (Z(av)) 2.40. (GeTe4)(100 - x)(As2Se3)(x) glasses in the range 5 <= x <= 15 exhibit two stage crystallization whereas glasses with x > 15 exhibit single stage crystallization. Annealing of the glasses results into hexagonal GeTe and Te structures for 0 <= x <= 10 whereas glasses in the range 15 <= x <= 40 show only Te crystallites. For higher As2Se3 mol. % (x >= 50) As2Te3 phase along with Te has been observed. Raman studies indicate the presence of GeSe2, GeTe2, As2Te3, and -Te-Te-structural units. The average coordination number of the glasses prepared in this tie-line is 2.4. Though the overall bond energy of the system increases with the increase of As2Se3, the density (rho), glass transition (T-g) and specific heat capacity (Delta C-p) show a decreasing trend. The rate of decrease of rho, T-g and Delta C-p is slow for 0 <= x < 25 and rapid for 25 <= x <= 40. These results indicate that the rigidity of the structural network decreases with an increase of As2Se3 though the average coordination number remains constant for the entire range of composition. (C) 2016 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 08 Oct 2016 07:22
Last Modified: 08 Oct 2016 07:22
URI: http://eprints.iisc.ac.in/id/eprint/54928

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