A molecular dynamics model of the atomic structure of dysprosium alumino-phosphate glass

Martin, Richard A. and Mountjoy, Gavin and Newport, Robert J. (2009) A molecular dynamics model of the atomic structure of dysprosium alumino-phosphate glass. Journal of Physics: Condensed Matter, 21 (7). 075102. ISSN 0953-8984. (Full text available)

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http://dx.doi.org/07510210.1088/0953-8984/21/7/075...

Abstract

Molecular dynamics (MD) has been used to identify the relative distribution of dysprosium in the phosphate glass DyAl0.30P3.05O9.62. The MD model has been compared directly with experimental data obtained from neutron diffraction to enable a detailed comparison beyond the total structure factor level. The MD simulation gives Dy ... Dy correlations at 3.80(5) and 6.40(5) angstrom with relative coordination numbers of 0.8(1) and 7.3(5), thus providing evidence of minority rare-earth clustering within these glasses. The nearest neighbour Dy-O peak occurs at 2.30 angstrom with each Dy atom having on average 5.8 nearest neighbour oxygen atoms. The MD simulation is consistent with the phosphate network model based on interlinked PO4 tetrahedra where the addition of network modifiers Dy3+ depolymerizes the phosphate network through the breakage of P-(O)-P bonds whilst leaving the tetrahedral units intact. The role of aluminium within the network has been taken into explicit account, and A1 is found to be predominantly (78%) tetrahedrally coordinated. In fact all four A1 bonds are found to be to P (via an oxygen atom) with negligible amounts of Al-O-Dy bonds present. This provides an important insight into the role of Al additives in improving the mechanical properties of these glasses.

Item Type: Article
Additional information: ISI Document Delivery No.: 400VK Times Cited: 0 Cited Reference Count: 43 Martin, Richard A. Mountjoy, Gavin Newport, Robert J.
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: J.M. Smith
Date Deposited: 13 May 2009 14:06
Last Modified: 30 May 2014 11:13
Resource URI: http://kar.kent.ac.uk/id/eprint/15918 (The current URI for this page, for reference purposes)
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