Size effects on the order-disorder transition of binary alloy clusters, particularly Fe-(Pd, Pt) clusters, are studied theoretically, based on the theory of Bragg and Williams. Including the broken bonds at surfaces (interfaces) of the clusters, the relationship between the degree of order and the cluster size, which has recently been suggested from various experimental studies, is formulated. The dependences of the critical size on the temperature and the order-disorder transformation temperature on the cluster size are derived. There is a slight quantitative disagreement with experiment, but this may be improved by considering some modification of higher-order terms.
ASJC Scopus subject areas
- Condensed Matter Physics