Effect of Mo content on the structure stability of R3(Fe,Co,Mo)29

Formation of Ce3Fe29-x-yCoxMoy(x=0,3,6,10) compounds has been investigated by means of x-ray diffraction and magnetic measurements. It is found that the required Mo content to stabilize the 3:29 compounds decreases monotonically as Co content increases, totally different from the discovery in the Gd-3(Fe1-xCox)(29-y)Cr-y compounds. Meanwhile, we adopted a lattice inversion method in acquiring the interatomic potentials to rare-earth-transition metal intermetallic compounds, and investigated the substitution behaviors of Mo, Cr, V, and Mn in Fe-based and Co-based 3:29 compounds, respectively, by combining these potentials with computer simulation. The calculated results show that the required Mo content in R3Co29-xMox compounds is lower than that in R3Fe29-xMox compounds, whereas the Cr content in R3Co29-xCrx compounds higher than that in R3Fe29-xCrx compounds, coinciding well with the previous discovery and the experimental results in this work. (C) 2003 American Institute of Physics.