XAFS STUDY OF CE VALENCE IN THE CE1-XYXFE2 SYSTEM

Pseudo binary alloys like R(A(1-x)B(x))(2) compounds are known to exhi bit both negative and positive types of deviation from Vegard's law on substitution of 3d or 4f cations. CeNi2 based alloys are known to be mixed valence compounds whereas CeFe2 alloys are probably not. In this study we examine the influence of substitution of rare earth compound s rather than the 3d ions. Ce L(III) absorption edge XAFS is measured in the single phase Ce1-xYxFe2 system (x = 0.0, 0.1, 0.2, 0.3 and 0.7) using the super ACO synchrotron radiation facility at LURE. The spect ra are discussed in terms of the change in the Ce valence as a result of progressive substitution by trivalent Y cation. The problem of Ce v alence saturation is also addressed in this work.