Bowron, Daniel Timothy and Saunders, George A. and Newport, Robert J. and Rainford, B.D. and Senin, H.B. (1996) EXAFS studies of rare-earth metaphosphate glasses. Physical Review B: Condensed Matter and Materials Physics, 53 (9). pp. 5268-5275. ISSN 0163-1829. (Full text available)
An extended x-ray-absorption fine structure (EXAFS) study has been carried out on a range of rare-earth metaphosphate R(PO3)(3) glasses of growing interest in optical communications and laser technologies. Phosphate glasses modified using the rare-earth oxides Pr6O11, Nd2O3, Eu2O3, Gd2O3, Tb2O3, and Ho2O3, have been investigated using their respective rare-earth L(III) absorption edges. The data provide information on the local environment of the rare-earth ion within the phosphate glass matrix constructed from linked PO4 tetrahedra. The rare-earth ions occupy sites with an average coordination number in the range, 6 less than or equal to N less than or equal to 8, the surrounding atoms being oxygen. The first shell interatomic distance over the range of rare-earth ions establishes the rare-earth contraction of ionic radii with increasing atomic number in a series of glasses. There is also evidence for a rare-earth-phosphorus correlation between 2.7 and 3.6 Angstrom: and a further rare-earth-oxygen correlation at approximately 4 Angstrom. The EXAFS spectrum shows no evidence for R-R correlations within the short-range order, a result especially pertinent to the optical and magnetic properties of the glasses. The fractal dimensionality 4C(11)/B of these glasses, obtained from the elastic stiffnesses determined from ultrasonic wave velocities, ranges between 2.3 and 2.8, indicating that their connectivity tends towards having a three-dimensional character.
|Divisions:||Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group|
|Depositing User:||J.M. Smith|
|Date Deposited:||29 Apr 2009 14:06|
|Last Modified:||17 Jul 2014 11:55|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/15869 (The current URI for this page, for reference purposes)|