Modification of magnetic properties in Fe–Ni alloy thin films induced by energetic ion irradiation

Ion irradiation effects on magnetic properties in Fe–Ni alloy thin films are studied. The specimens of Fe–Ni alloy thin films (∼500 nm in thickness) are irradiated at room temperature with several kinds of ions in the energy and mass ranges of 1.0–200 MeV and 1H–197Au. A large increase in TC is observed for comparatively lower energy and lighter ion irradiation. These results suggest that the dominant energy transfer process for the modification of magnetic properties in Fe–Ni alloys is the elastic interaction between incident ions and target atoms. The dependence on ion energy, mass and fluence of the change in TC gives information on a dominant irradiation parameter.