GIANT MAGNETORESISTANCE OF NANOWIRES OF MULTILAYERS

A new technique is required which enables tailoring of the morphology of a metallic nanostructured material down to the 10 nm length scale. Using nanoporous nuclear track etched membranes as templates for elect rodeposition, an assembly of wires with diameters as low as 30 nm coul d be obtained. Alternating the electrodeposition of two metals resulte d in multilayers grown perpendicular to the wire axis. Layer thickness es as low as 2 nm could be reached. Application is demonstrated by mak ing wires 6 mum long, 80 nm in diameter, having a succession of either Co and Cu layers or of (Ni,Fe) and Cu layers. Wires containing layers of 5-10 nm in thickness exhibited a giant magnetoresistance. The curr ent was naturally perpendicular to the layers. At ambient temperature, a magnetoresistance of 14% for Co/Cu and of 10% for (Fe,Ni)/Cu was ob served. (C) 1994 American Institute of Physics.