Internal friction and vulnerability of mixed alkali glasses.

Based on a hopping model we show how the mixed alkali effect in glasses can be understood if only a small fraction c(V) of the available sites for the mobile ions is vacant. In particular, we reproduce the peculiar behavior of the internal friction and the steep fall ("vulnerability") of the mobility of the majority ion upon small replacements by the minority ion. The single and mixed alkali internal friction peaks are caused by ion-vacancy and ion-ion exchange processes. If c(V) is small, they can become comparable in height even at small mixing ratios. The large vulnerability is explained by a trapping of vacancies induced by the minority ions. Reasonable choices of model parameters yield typical behaviors found in experiments.

[1]  F. Berkemeier,et al.  Mixed-Alkali Effect of Tracer Diffusion and Ionic Conduction in Na-Rb Borate Glasses as a Function of Total Alkali Content , 2004 .

[2]  Á. Imre,et al.  Mixed-alkali effect in Na–Rb borate glasses: A tracer diffusion and electrical conductivity study , 2004 .

[3]  K. Ngai,et al.  "Cooperativity blockage" in the mixed alkali effect as revealed by molecular-dynamics simulations of alkali metasilicate glass. , 2004, The Journal of chemical physics.

[4]  A. Bunde,et al.  A new interpretation of the dynamic structure model of ion transport in molten and solid glasses , 2004, cond-mat/0405413.

[5]  J. Habasaki,et al.  Molecular dynamics study of the mechanism of ion transport in lithium silicate glasses: Characteristics of the potential energy surface and structures , 2004 .

[6]  S. Adams,et al.  Mixed alkali effect in glasses. , 2003, Physical review letters.

[7]  A. Heuer,et al.  Complete identification of alkali sites in ion conducting lithium silicate glasses: a computer study of ion dynamics. , 2003, Physical review letters.

[8]  J. Dyre.  Is there a ‘native’ band gap in ion conducting glasses? , 2002, cond-mat/0207722.

[9]  B. Liu,et al.  Formation of a dodecagonal phase in the nano-sized Ag-Pt multilayers upon solid-state reaction , 2002 .

[10]  W. Howells,et al.  Random ion distribution model: A structural approach to the mixed-alkali effect in glasses , 2001 .

[11]  R. Kirchheim.  The mixed alkali effect as a consequence of network density and site energy distribution , 2000 .

[12]  P. Maass.  Towards a theory for the mixed alkali effect in glasses , 1999 .

[13]  M. Schulz,et al.  A cooperative model for the mixed mobile ion effect in covalent glasses , 1998 .

[14]  H. Eckert,et al.  Local cation environments in mixed alkali silicate glasses studied by multinuclear single and double resonance magic-angle spinning NMR , 1997 .

[15]  Meyer,et al.  Mixed alkali effect in crystals of beta - and beta "-alumina structure. , 1996, Physical review letters.

[16]  Greaves Gn,et al.  Reconciling ionic-transport properties with atomic structure in oxide glasses. , 1995 .

[17]  W. Dieterich,et al.  Dynamic structure factor and acoustic attenuation in disordered solid electrolytes , 1995 .

[18]  A. Hunt.  An explanation for the Kauzmann ‘paradox’ and its relation to relaxation times , 1994 .

[19]  A. Bunde,et al.  The dynamic structure model for ion transport in glasses , 1994 .

[20]  Bunde,et al.  Ion transport anomalies in glasses. , 1992, Physical review letters.

[21]  B. Dobson,et al.  A structural basis for ionic diffusion in oxide glasses , 1991 .

[22]  D. Day,et al.  The internal friction of glasses , 1979 .

[23]  D. Day.  Mixed alkali glasses — Their properties and uses , 1976 .

[24]  D. Day,et al.  Diffusion and Internal Friction in Na-Rb Silicate Glasses , 1970 .

[25]  O. Anderson,et al.  Calculation of Activation Energy of Ionic Conductivity in Silica Glasses by Classical Methods , 1954 .

[26]  M. Tomozawa.  The mixed alkali effect and thermodynamic state of glasses , 1998 .