Swift ion irradiation of magnetostrictive multilayers

The modification of the magnetic and magnetostrictive properties of TbFe2/Co exchange-coupled multilayers irradiated with 700 MeV Pb ions was investigated as a function of ion fluence. After irradiation, the magnetostrictive properties of the sample are first strongly improved up to a fluence of 1 × 1012 ions cm−2 where the magnetoelastic susceptibility is six times higher than for the as-deposited sample. This effect is ascribed to stress relaxation and Fe-Co intermixing at the interfaces. For higher fluences, the magnetostrictive properties do not vary further, indicating a stationary state of mixing.