Structural and chemical effects onEELSL3,2ionization edges in

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 ͑ELNES͒ 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 ͑DOS͒ 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.

H2-induced environmental embrittlement in ordered and disordered Ni3Fe: An electronic structure approach

“…This assumption can be valid when changes in 3d occupancies of Ni atoms in the Ni-based intermetallics is less than 0.1 electrons/atom estimated by Verbeeck et al [12]. Changes between 3d occupancies of Ni atoms in ordered Ni 3 Fe and those in disordered Ni 3 Fe are 0.07 electrons/atom, satisfying the condition as mentioned above.…”

“…On the other hand, the absence of charge transfer, called local charge neutrality, is very important for the interpretation of chemical shifts in EELS [11,12]. This assumption can be valid when changes in 3d occupancies of Ni atoms in the Ni-based intermetallics is less than 0.1 electrons/atom estimated by Verbeeck et al [12].…”

“…The onset energy of the L 2,3 edges of Ni from disordered phase is 0.3 eV higher than that from ordered phase. is based on two key assumptions: the absence of many-body effects and the absence of charge transfer among atoms [12].…”

Long-range order of Ni2+ and Mn4+ and ferromagnetism in multiferroic (Bi0.9La0.1)2NiMnO6 thin films

“…The determined fine structure of these L 2,3 edges corresponds to the divalent oxidation state. 20 We now turn on to the magnetic properties. Data of previous paragraphs clearly indicates that BLNMO films are B-site ordered, fully stoichiometric and the electronic configuration of Ni 2+ and Mn 4+ ions are those required for ferromagnetic coupling.…”

TEM characterization of Al–C–Cu–Al2O3 composites produced by mechanical milling

“…EELS allows the study of precipitates, grain boundaries, internal interfaces and other atomic interactions through the analysis of the energy loss near edge structure (ELNES) [10][11][12].…”