By following the experimental results recently Published about electronic-energy-deposition-induced effects in metallic materials, a mixing effect is observed in an Fe/Si multilayer irradiated by 650 MeV uranium ions. Mossbauer spectroscopy shows that, after a fluence as low as 10(13)cm-2, an Fe 4.5-nm/Si 3.5 nm multilayer has been made almost homogeneous by ion mixing. On electron micrographs, at very low fluence, latent tracks are observed where the magnetic properties are drastically modified from the previous crystalline ferromagnetic state.