TDCS for photo-double ionization of helium have been measured in a PhotoElectron-PhotoElectron COincidence (PEPECO) experiment. The TDCS have been obtained for the first time at very low excess energies E, 0.6 eV

The Ar 2+ and Ne 2+ spectra have been studied from their respective thresholds up to their respective triple ionization potentials by threshold photoelectrons coincidence (TPEsCO) spectroscopy. The np 4 , nsnp 5 and ns 0 np 6 (n = 2, 3 in Ne and Ar, respectively) states of the dications as well as the np 3 n l satellite states, where two electrons are ejected and one is promoted into an unfilled orbital, have been observed. This study is the first extensive observation of the satellite states of dications by electron emission spectroscopy and extends the previous observations by optical emission spectroscopy to the region of the triple ionization threshold. New features have been discerned in the spectra and an assignment is proposed based on previous results from optical spectroscopy and on calculations with an atomic multiconfigurational Dirac-Fock code.

We investigated the use of the focused ion-beam (FIB) technique as a nanofabrication tool for the implementation of oxide-based magnetic and magnetoelectronic functional devices. In particular, we studied the effect of using FIB lithography for the patterning of La(2/3)Ca(1/3)MnO(3) magnetic oxide thin films. Results obtained show that the transport properties of patterned areas were strongly degraded after the patterning process. In contrast, no degradation was detected when the patterning was performed using a less aggressive technique. The origin of this degradation correlates with Ga(+) ion implantation, as indicated by Auger spectroscopy analysis of the patterned films.

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The metastable excitation function and the near-threshold energy loss spectrum in potassium, corresponding to 3p 6 core excitation, have been measured over the energy range 18-24 eV. Many structures have been observed for the first time in the metastable excitation function. From a comparison of the observed yields of metastable atoms and scattered electrons, various processes for metastable production are considered, including resonance excitation and radiative cascade. The excitation thresholds for the lowest-lying metastable autoionizing levels in potassium, namely 3p 5 4s4p 4 D 7/2 and 3p 5 3d4s 4 F 9/2 , have been determined to be 20.28 ± 0.05 eV and 20.42 ± 0.05 eV, respectively.

The transport properties across perovskite oxides heterointerfaces are analyzed. Epitaxial La(2/3)Ca(1/3)MnO3/SrTiO3 (LCMO/STO) heterostructures with different STO insulating-barrier thicknesses are systematically investigated and their behavior compared with LCMO/metal junctions. Atomic force microscopy (AFM) measurements in current-sensing mode show typical features associated with tunneling conduction. Careful analysis of the I-V curves across LCMO/STO heterointerfaces, using the Simmons model in the intermediate voltage range, clearly shows the existence of an interface-induced enhancement of the tunneling barrier of about 1.6 nm on the LCMO side. These results confirm recent theoretical studies predicting electronic phase segregation and the formation of an orbital-ordered insulating phase at the manganite-insulator interface that is a result of the reduction in the number of charge carriers at the interface.

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