Effect of N+ irradiation on the microstructural and magnetic properties of Co/Pd multilayers

Microstructural and magnetic properties of N-14(+) irradiated Co/Pd multilayers, deposited on ultra-flat large (2.5 in) glass substrates by a special hard disk industrial manufacturing system, are discussed. Upon irradiation with 14N+ ions at different energies (20-30 keV) and doses (10(14)-10(15) ions/cm(2)), both the coercive and nucleation fields were found to change with respect to as deposited multilayer. Results indicate that the irradiation process leads to a lowering of the magnetic anisotropy due to the induced disorder and degradation of the interface quality: for an energy of 30 keV, at an irradiation level of 10(15) ions/cm(2), H-c reduces from H-c approximate to 5.4 kOe for the as deposited multilayer down to 300 Oe, being the easy axis still perpendicular to the multilayer plane; at the highest dose (10(16) ions/cm(2)), the coercivity vanishes and the perpendicular anisotropy is suppressed.