Polarization-dependent EXAFS studies of chemical and structural anisotropy in sputter-deposited Co78Cr22 films

Extended x-ray absorption fine structure measurements of a Co₇₈Cr₂₂ film were performed using normal and glancing incident radiation in order to investigate, respectively, the in-plane and out-of-plane local structure and chemistry. The Fourier transformed EXAFS data illustrates the presence of an anisotropy between the in-plane and out-of-plane structures around Co and Cr atoms. Analysis of the local environments around Co for the two sample orientations indicates the presence of Co-rich clusters, while fitting of the Cr environment indicates preferential ordering parallel to the film plane. These results are consistent with earlier reports of a high density of stacking faults perpendicular to the growth axis, supporting the interpretation that a platelet-like texturing exists within the columnar microstructure. Cr segregation parallel to the film plane provides diffusion paths allowing for transverse compositional inhomogeneities observed in TEM studies