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 14x76 mu m2 in size and consist of 12 layers of Co thin film with the thickness of 20 Angstrom and 11 layers of Cu thin film with the thickness of 13-22 Angstrom 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 Angstrom)/Cu(21 Angstrom) multilayer. Experimental results show precise controllability of the thickness and the additional capability of the focused ion-beam direct deposition method. (C) 1996 American Institute of Physics.