Monte Carlo simulation on the cation diffusion via vacancies in simple spinels

Abstract

The correlation factors of cations and vacancies for diffusion in simple spinels were calculated by using the Monte Carlo simulation technique. Since the predominant point defects are cationic vacancies at high temperature and especially at high oxygen partial pressures in many spinels, the cations are considered to move primarily via cationic vacancies in this study. Several input parameters including the lattice size, the number of jumps per cation. etc., were optimized to calculate the correlation factors. Then the correlation factors of cations moving via vacancies in simple spinels were calculated in different types of exchange jumps, i.e., diffusion that occurs on tetrahedral or octahedral or both cationic sites. Results were obtained with satisfactory accuracy. The influence of the vacancy concentration on the correlation factors was also analyzed. (C) 1999 Elsevier Science B.V. All rights reserved.