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We have measured the Ti+ and O- secondary ion emission yields of a Ti sample exposed to oxygen. The oxygen amount at the surface was determined by measuring the OKLL Auger signal, and the chemical effect of oxygen at the surface by measuring the TiLMV and TiLMM Auger line shapes. We found that the oxidation process of Ti presents two clearly differentiated regimes characterized by a different electronic transfer mechanism from titanium to oxygen. These two regimes are also observed in the behavior of the Ti+ and O- yields showing a correlation between the ionization mechanism and the chemical surrounding of the ejected atom.

Multilayer structures consisting of YBaCuO, Al2O3 and CuO have been sputtered on various substrates. Resistivity measurements show almost no deterioration of the electrical properties of a superconducting YBaCuO film, on top of which first an A12O3 and then an YBaCuO film has been sputtered. First results of YBaCuO films deposited on the A12O3 barrier show a Tcof 65 K.