Magnetotransport and domain structures in nanoscale NiFe/Cu/Co spin valve

Nanoscale spin-valve structures with a width as small as 70 nm were fabricated using nanoimprint lithography and ion milling or lift off. The spin-valve multilayers consisting of NiFe(10 nm)/Co(1 nm)/Cu(13 nm)/Co(10 nm)/NiFe(2 nm) were deposited using direct current sputtering. The effects of device size, as well as fabrication process on domain structures, switching fields, switching field variation, and giant magnetoresistive ratio were investigated using scanning electron microscopy, atomic force microscopy, magnetic force microscopy, and magnetoresistance measurements.