Regensburg 2004 – scientific programme
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.10: Poster
Thursday, March 11, 2004, 16:00–18:00, Poster D
Vacancy model for the mixed alkali effect — •Robby Peibst, Stephan Schott, Hartmut Grille, and Philipp Maass — Institut für Physik, Technische Universität Ilmenau, Germany
In ionically conducting glasses, all properties
associated
with long-range ionic motion show large deviations from a simple additive
behavior upon mixing of two different types of mobile ions. This phenomenon
is
called the mixed alkali effect and is of particular theoretical interest
due
to its crucial role for the general understanding of ion transport in
glasses.
Recent molecular dynamics simulations and further general considerations
suggest that the number of vacant sites in the glassy network is rather
small.
Motivated by these findings and by taking into account the existence of
different energies of the ion sites [3], we discuss possible szenarios to
explain the mixed alkali effect by a vacancy mechanism.
[1] H. Lammert, M. Kunow, and A. Heuer, Phys. Rev. Lett. 90,
215901 (2003)
[2] J. Habasaki and Y. Hiwatari, Phys. Rev. B, in print
[3] Ph. Maass, J. Non-Cryst. Solids 255, 35 (1999)