Improving the quality of AMR of permalloy films by N2+ ion irradiation

To systematically investigate the influence on physical properties of magnetic materials irradiated by energetic ion, permalloy films were irradiated by 80 keV N2+ ions to a range of fluences. A post-processing approach by ion irradiation was found to improve the quality of AMR of permalloy films in the case of no significant influence on the crystal structure, the static and dynamic magnetic properties. Ion irradiation decreases Hc, ΔH0 and R0, and increases ΔR at the highest fluence. We infer that the main factor affecting the physical properties of the films irradiated by N2+ ions is ion-beam-induced annealing effect.