Mixed Ion-Polaron Transport in Na2O-PbO-Fe2O3-P2O5 Glasses

Author

A. Moguš-Milanković
A. Šantić
Signo Tadeu Dos Reis, Missouri University of Science and Technology
K. Furić
D. E. Day, Missouri University of Science and TechnologyFollow

Abstract

The electrical and dielectric properties of the xNa₂O · (100 - x) · [28.3PbO · 28.7Fe₂O₃ · 43.0P₂O₅] (0 ≤ x ≤ 30) glasses were measured by impedance spectroscopy in the frequency range from 0.01 Hz to 3 MHz and the temperature range from 303 to 473 K. the conductivity for glasses containing ≤15 mol% Na₂O is predominantly electronic and is controlled by electron hopping between Fe(II) and Fe(III) ions. in these glasses the sodium ions have such a low mobility, caused by ion-polaron interaction, that they make no detectable contribution to the total conductivity. for Na2O contents >15 mol%, the conductivity increases significantly due to an increase in the sodium ion mobility. the increasing concentration of sodium ions, increases the degree of disorder in the glass network, with an increase in the number of non-bridging oxygens. This in turn enhances the pathways suitable for migration of the sodium ions responsible for an increase in the ionic conductivity. the dielectric properties, such as ε′(ω) and ε′(ω), and their variation with frequency and temperature indicates an increase in electrode polarization, which reduces the dipolar relaxation effects. the structural changes in these glasses have been investigated by Raman and IR spectroscopy. the Raman spectra show that with increasing Na₂O content there is corresponding reduction in number of the Q¹ phosphate units and an increase in non-bridging oxygens as more Q⁰ phosphate units are formed in the glass network. the decrease in glass temperature, T_g and glass density, D, is due to the lower degree of cross-bonding between the sodium and non-bridging oxygens in Q⁰ phosphate units resulting in a weakening of the glass network. © 2004 Elsevier B.V. All rights reserved.

Recommended Citation

A. Moguš-Milanković et al., "Mixed Ion-Polaron Transport in Na2O-PbO-Fe2O3-P2O5 Glasses," Journal of Non-Crystalline Solids, vol. 342, no. 1 thru 3, pp. 97 - 109, Elsevier, Aug 2004.

The definitive version is available at https://doi.org/10.1016/j.jnoncrysol.2004.07.012

Department(s)

Materials Science and Engineering

Comments

International Atomic Energy Agency, Grant 10638/R

International Standard Serial Number (ISSN)

0022-3093

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

15 Aug 2004