Computer simulation of 'order-order' kinetics in L1_2 superstructure

摘要

Monte Carlo simulations of long-range order (LRO) relaxation in A_3B system with L1_2 superstructure have been performed within a model based on a vacancy jump mechanism between nearest neighbour sites. Systematic studies involved different vacancy concentrations, different sets of pair interaction potentials, as well as different activation barriers for the migration of A- or B-atoms. The dependence of resulting relaxation times on vacancy concentration has been checked. Previously proposed model of the origin of the experimentally observed two (fast and slow) parallel relaxation processes has been supported. It was found that the fast relaxation is damped when high activation barriers are assumed to act between the majority A-atoms. Contribution of particular kinds of atomic jumps to the overall LRO relaxation was monitored.