Test of Anderson-Stuart model and the "universal" conductivity in rubidium and cesium silicate glasses

• Autor(a) principal: Nascimento,Marcio Luis Ferreira
• Data de Publicação: 2005
• Outros Autores: Nascimento,Eduardo do, Watanabe,Shigueo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Physics
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332005000400007

An analysis and brief discussion of experimental ionic conductivity sigma and activation energy E A in the binary rubidium and cesium silicate systems is presented, exemplified on 23 and 30 glasses respectively, in a wide composition range (5-45 Rb2O and Cs2O mole%). The Anderson and Stuart model has been considered to describe the variation of activation energy E A with alkali concentration in both alkali-silica systems. In this analysis were considered experimental parameters, like shear modulus G and relative dielectric permittivity epsilon. An "universal" finding is obtained using logsigma× E A/kB T in 51 of 53 glasses considering both alkali systems, where E A is the activation energy for conduction, kB is the Boltzmann constant and T is the absolute temperature. This strong correlation by more than 13 (Rb-based glasses) and 15 (Cs-based glasses) orders of magnitude means that sigma is governed mainly by E A. An explanation for this behavior links ionic conductivity and microscopic structure.