E. Colavita

Extended ELS fine structures above the M2,3 edges of Cu and Ni

Abstract Very detailed electron energy loss spectra of M2,3 core levels of Cu and Ni in the reflection mode are presented. A careful analysis of the oscillations up to about 300 eV above the edges shows strict analogies to EXAFS and demonstrates that structural information can be obtained with this technique. A comparison with X-ray results above the Cu and Ni K-edges shows that very high accuracy in the radial distribution function can be obtained also with ELS spectra taken above shallow core levels.

Electronic properties of Fe80B20 alloys: ordering and disordering effects

The electronic properties of amorphous and sintered Fe80B20 alloys have been studied by electron energy loss and Auger spectroscopy. A correlation has been attempted between data which have appeared recently in the literature on energy loss and X-ray absorption near edge structures. The comparison of Fe-B spectra with those of Fe and Ni allows the authors to discriminate between the effects due to the presence of the metalloid and those due to disorder. A suggestive relationship between the data and the local environment around each Fe site has been found and discussed.

Radial distribution functions of Cu and Ni by reflection energy loss spectroscopy

Abstract Electron energy loss spectra of M 23 core levels of Cu and Ni in the reflection mode are reported. The analysis of the oscillations up to about 300 eV above the edges shows strict analogies to EXAFS. A comparison with X-ray results above Cu and Ni K edges shows that high accuracy in the radial distribution function (RDF) can be obtained also by ELS spectra taken above shallow core levels. The present technique has several advantages over conventional absorption of X-ray and transmission EELFS measurements. In particular thin film samples are not required and measurements of surface effects, such as relaxation and adsorbate structure determination, become feasible.

Surface extended energy loss fine structures above the K-edge of oxygen on Al

Abstract Surface Extended Energy Loss Fine Structures (SEELFS) have been detected above the K-edge of oxygen adsorbed on an Al sample. This is the first evidence that the local geometry of adsorbates on metal surfaces can be investigated with the electron energy loss technique in the reflection mode. This experimental technique is highly surface sensitive and accurate bond lengths can be obtained. The oxidation model implied by our results for the OAl system is in agreement with data in the literature.

Multipole and spin-flip interband transitions in the electron energy loss of ferromagnetic Fe

Abstract Electron energy loss measurements have been carried out in the reflection mode from polycrystalline iron. The observed structures are interpreted as surface and bulk collective losses by observing their dependence on the primary electron energy and surface oxidation. Interband transitions in the range 2–30 eV are pinpointed and found to be in excellent agreement with previous optical results, except for a new strong transition around 10 eV, which is not found in optical experiments. This transition is tentatively identified with a dipole-forbidden process, which becomes allowed because of finite momentum transfer by the electrons.

Structure-related effects in the electronic properties of Fe80B20 alloys

Abstract The electronic properties of the amorphous and sintered Fe80B20 alloys have been studied by electron energy loss spectroscopy. A correlation among energy loss data and X-ray absorption near edge structures has been attempted. Structure-related effects in the electronic properties of Fe80B20 alloy have been found and discussed.

XANES and EXAFS Measurements on Pd2Si: One-Electron or Many Body Effects?

X-ray absorption spectroscopy has been used to investigate near L-edge structures of Pd in pure Pd and bulk Pd2Si and PdSi silicides (1).

Reflection Extended Energy Loss Fine Structures Above Ti L2,3 Edge: A Comparison with EXAFS Results

We present a reflection energy loss investigation of the Ti L2,3 edge. The oscillations detected above the core-edge have been analyzed following the standard EXAFS-procedure in order to obtain the radial distribution function around the excited central atom.