Structural and chemical effects onEELSL3,2ionization edges inNi−basedintermetallic compounds

Abstract

EELS ${L}_{3,2}$ ionization edges in several Ni-based intermetallic compounds have been studied and interpreted in terms of the distribution of electrons in the valence d bands. It is demonstrated that the integral EELS cross sections change only slightly upon the formation of intermetallic compounds and, therefore, the charge transfer between atoms is negligible. On the other hand, changes in the energy loss near edge fine structure (ELNES) of the Ni ${L}_{3}$ edge can be readily detected, indicating an important redistribution of d electrons at the Ni site. Full-potential linearized augmented-plane-wave calculations of the density of states (DOS) and simulations of the Ni ${L}_{3}$ edge EELS profiles show that these changes correspond to a hybridization between the Ni d band and d bands of the alloying elements. In contrast, structural transformations in the investigated intermetallic compounds do not significantly affect the ELNES as the typical energy resolution of EELS is not sufficient to track the slight difference in the DOS between various structural modifications of intermetallic compounds.