GIANT MAGNETORESISTANCE IN CO/CU MULTILAYERS FABRICATED BY FOCUSED ION-BEAM DIRECT DEPOSITION

We report the direct deposition of patterned multilayers that exhibit giant magnetoresistance without any lithographic processes. We fabricated Co/Cu multilayers by the focused ion‐beam direct deposition method and measured the magnetoresistance characteristics of the multilayers. The fabricated Co/Cu multilayers are 14×76 μm2 in size and consist of 12 layers of Co thin film with the thickness of 20 A and 11 layers of Cu thin film with the thickness of 13–22 A on the GaAs substrate. We used a 108 eV Co2+ ion beam and 54 eV Cu+ ion beam extracted from a Co–Cu–Au–Nb alloy ion source. The measured magnetoresistance ratio of giant magnetoresistance was 6.7% in the case of the Co(20 A)/Cu(21 A) multilayer. Experimental results show precise controllability of the thickness and the additional capability of the focused ion‐beam direct deposition method.