  Nanostrucured Europium oxide and hydroxide films were obtained by pulsed
Nd:Yag (532 nm) laser ablation of an Europium metallic target, in the presence
of a 1 mbar Helium buffer atmosphere. Both the produced film and the ambient
plasma were characterized. The plasma was monitored by an electrostatic probe,
for plume expansion in vacuum or in the presence of the buffer atmosphere. The
time evolution of the ion saturation current was obtained for several probe to
substrate distances. The results show the splitting of the plume into two
velocity groups, being the lower velocity profile associated with metal cluster
formation within the plume. The films were obtained in the presence of helium
atmosphere, for several target to substrate distances. They were analyzed by
Rutherford backscattering spectrometry (RBS), X-Ray Diffraction (XRD) and
Atomic Force Microscopy, for samples as-deposited and treated at 600 degrees C
in air. The results show that the as-deposited samples are amorphous and have
chemical composition compatible with Europium hydroxide. The thermally treated
samples show X-Ray diffraction peaks of Eu_2O_3, with chemical composition
showing excess oxygen. Film nanostructuring was shown to be strongly correlated
to cluster formation, as shown by velocity splitting in probe current versus
time plots.
