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Thin films of silica containing 0.15 at.% Eu and 3.5 to 7 at.% Na were prepared by sol–gel chemistry and annealed at 600 ° C in air, then submitted to ion–exchange treatments in NaNO3 : AgNO3 for studying the effect of the plasmon resonance of Ag nanoparticles on the excitation of Eu3+ ions. When excited at other wavelengths in the UV other than that corresponding to the 7F0–5L6 transitions of the Eu3+ ions, the yield of the 5D0–7F2 emission is increased by a factor of the order of 10 in films containing Ag particles with respect to that in non-exchanged films.

We report on synthesis of spherical Au nanoparticles at the surface and embedded in carbonaceous matrix by 150 keV Ar ion irradiation of thin Au film on polyethyleneterepthlate (PET). The pristine and irradiated samples are characterized by Rutherford backscattering spectrometry (RBS), atomic force microscopy, scanning electron microscopy and transmission electron microscopy (TEM) techniques. RBS spectra reveal the sputtering of Au film and interface mixing, increasing with increasing fluence. Surface morphology shows that at the fluence of 5 × 1015 ions cm−2, dewetting of thin Au film begins and partially connected nanostructures are formed whereas, at the higher fluence of 5 × 1016 ions cm−2, isolated spherical Au nanoparticles (45 ± 20 nm) are formed at the surface. Cross-sectional TEM observations also evidence the Au nanoparticles at the surface and mixed metal–polymer region indicating the formation of nanocomposites with small Au nanoparticles. The results are explained by the crater formation, sputtering followed by dewetting of the thin Au film and interdiffusion at the interface, through molten zones due to thermal spike induced by Ar ions.

Particles of the FePt intermetallic compound with L1(0) structure embedded in silica films were submitted to irradiation by 120 MeV Au ions at different fluences. Observations by transmission electron microscopy evidenced an elongation of the particles, ascribed to an anisotropic ripening process during the thermal spikes occurring in the wake of the ions. However, the observed changes in the magnetic properties are attributed to the magnetostriction of the particles. Their compression by the matrix induces a tilt of easy magnetization axis from in-plane to perpendicular to the film surface, together with an increase in coercivity.