Influence of network modifiers on conductivity and relaxation parameters in some series of fluoride glasses containing LiF

✍ Scribed by J.M. Réau; Xu Yong Jun; J. Senegas; Ch. Le Deit; M. Poulain

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 647 KB
• Volume: 95
• Category: Article
• ISSN: 0167-2738
• DOI: 10.1016/s0167-2738(96)00564-4

✦ Synopsis

A new series of fluoride glasses of formulation ZrF,(0.25)-ZnF,(O.l5)-YF,(0.05)-AlF,(O.10)-CdF,(0.17 -2x/5)-BaFJ0.28 -3x/5)-LiF(x) and containing a wide LiF concentration range (0 Ix L,F 5 0.35) has been investigated by impedance spectroscopy: the variation of various electrical parameters has been determined as a function of composition. The results obtained with two other series of fluoride glasses covering the (0 5 xLIF 5 0.30) and (0.20 5 xLiF 5 0.60) concentration ranges are confirmed. A conductivity minimum associated with an activation energy maximum and a minimum of the decoupling index R,(T,) takes place for xLiF ~0.20. It is explained by the crossing with increasing x from a conductivity due preferentially to F -ions to a conductivity due preferentially to Li+ ions. Within each series, the composition relative to conductivity minimum offers a value r = 1 of the (xLIF/xBaFJ ratio. For higher xLIF rates, the p conductivity relaxation parameter involves also a minimum. Comparison of various series studied indicates that the composition relative to p minimum offers a value r=2 of the (xLiFIxeaF J ratio. The structural origin of the p minimum is confirmed.