He + ion irradiation study of continuous and patterned Co ∕ Pd multilayers

Ion irradiation of continuous and patterned ( Co ∕ Pd ) n magnetic multilayer films has been studied as a mean to control magnetic anisotropy as well as to evaluate possible ion irradiation damage involved in ion-beam proximity lithography patterning. The coercivity of patterned medium was found to decrease from 11 kOe for as patterned samples to 0.3 kOe for samples with 800 μ C ∕ cm 2 ion irradiation. Remnant squareness of the patterned samples remained essentially unchanged. As the number of bilayers increases in the sample, the effects vary, suggesting that several mechanisms of damage occur. Significantly, for typical irradiation doses used in ion-beam proximity lithography, no measurable alteration of magnetic properties was observed.