Tuning exchange bias effects by ion-beam bombardment in NiFe/NiO bilayers

We have studied the correlation between the ion-beam bombardment and exchange bias effects in NiFe/NiO bilayers. The dependence of the exchange bias field, H ex , with increasing V EH suggests strongly that the Ar ion-beam bombardment process may increase the spin misalignment in FM/AF interfaces (resulting in a decrease of H ex ) or create uncompensated NiO spins (shown by a shift from negative to positive H ex ), depending on the energy used. The polarity switch from −H ex to +H ex occurred with increasing ion-beam bombardment time (t bom. ≫ 5 mins).