Atomic-scale structure of Gd_xFe_100-x melt-quenched amorphous alloys (x = 22, 33, 56) by X-ray diffraction

The total atomic distribution functions for melt-quenched Gd_xFe_100-x amorphous alloys (x = 22, 33, 56) have been determined by X-ray diffraction. The partial atomic distances and coordination numbers for the alloys investigated have been obtained by fitting the first peak of their experimental atomic distribution functions with Gaussians. A comparison between the experimental coordination numbers and those predicted by a simple model for statistically distributed atoms has been made. Within the frames of this comparison the alloy of low Gd content (x = 22) has been found to be well represented by an assembly of almost statistically distributed Gd and Fe atoms, while the alloys of higher Gd content (x = 33, 56) exhibit a slight tendency to microsegregation. A comparison between the structural characteristics of the melt-spun amorphous alloys studied here and those of sputtered thin films of similar chemical composition investigated in other studies has also been made. Small but not negligible structural differences between the two types Gd-Fe amorphous materials considered have been found.