Ab initio calculation to predict the possible nonequilibrium A3B and AB3 states in the Co-Mo system

Ab initio calculations were carried out by means of the Vienna ab initio simulation package (VASP) to predict the possible nonequilibrium states in the Co-Mo system. At the composition of Co3Mo and CoMo3, the total energies are calculated for the four different structures, i.e. A15, D0(19), Ll(2), and L6(0), as a function of the lattice constant and some possible nonequilibrium states in the Co-Mo system are predicted, i.e. at a stoichiometry of Co3Mo with D0(19) structure and at COMo3 with an A15 structure. Experimentally, ion beam mixing of Co-enriched Co-Mo multilayers has resulted in the formation of a metastable hcp phase, which is in accordance with the predicted Co3Mo state and its crystalline structure as well as total energy. (C) 2003 Elsevier Science Ltd. All rights reserved.