IONIC-CONDUCTIVITY AND THE MIXED ALKALI EFFECT IN A BINARY-SYSTEM - A MONTE-CARLO STUDY

The ternary lattice gas comprising vacancies and the two atomic components A and B has been studied with Monte Carlo methods for vacancy contents up to 20%. The order/disorder ternary phase diagram was first determined prior to an investigation of the ionic conductivity of the atomic components. Similiar to the findings of Sato and coworkers using the Path Probability Method we found that correlation effects in the dc ionic conductivity are largely responsible for the mixed alkali effect. The correlation effects are somewhat stronger than predicted by Sato and coworkers. The behavior of the ionic conductivities was related to the detailed ordering behavior.