Application of glancing-emergent-angle fluorescence for polarized XAFS studies of single crystals

X-ray absorption fine-structure (XAFS) data were obtained for the V K-edge for a series of anisotropic single crystals of (Cr_xV_1-x)₂O₃. The data and the results were compared for the as-prepared bulk single crystals (measured in fluorescence in two different orientations) and those ground to powder (measured in transmission). For the bulk single crystals, the glancing-emergent-angle (GEA) method was used to minimize fluorescence distortion. The reliability of the GEA technique was tested by comparing the polarization-weighted single-crystal XAFS data with the experimental powder data. These data were found to be in excellent agreement throughout the entire energy range. Thus, it was possible to reliably measure individual V-V contributions parallel and perpendicular to the c axis of the single crystals, i.e. those unavailable by powder data XAFS analysis. These experiments demonstrate that GEA is a premiere method for non-destructive high-photon-count in situ studies of local structure in bulk single crystals.