Computer simulation of the diffusion isotope effect in a binary ordered alloy

Abstract

By means of Monte Carlo computer simulation, we have explored the extent of validity of the ‘impurity form’ of the tracer correlation factor in a model of the stoichiometric binary alloy (Ising magnet analogue). Above the order-disorder temperature the impurity form of the correlation factor appears to be valid. Below the order-disorder temperature, there is a deviation between the actual tracer correlation factor and that predicted by means of the impurity form, and this deviation increases substantially as the temperature decreases. These findings imply that the measured isotope effect in ordered alloys may not in fact be directly related to the usual tracer correlation factor.