The Local Structure of Amorphous Gd80Si12B8

We report the local structure of an amorphous alloy Gd80Si12B8 determined from an extended x-ray absorption fine structure (EXAFS) measurements near the Gd LIII edge. Analysis is made using an asymmetric pair distribution function. The distances from the Gd atom are 2.55 A to B, 2.96 A to Si and 3.50 A to Gd. The interatomic separation between Gd atoms is rather consistent with one for 12-coordinated metals, while the distances of Gd-B and Gd-Si are close to ones estimated from radii of atoms in tetrahedral covalent bonds rather than metallic radii. A central Gd atom has 11.4 nearest neighbors which consist of 0.9 B, 1.4 Si and 9.1 Gd atoms.