Giant magnetoresistance of nanowires of multilayers

TLDR

The study introduces a new technique to tailor metallic nanostructures down to 10 nm. The authors use nanoporous track‑etched membranes as templates for electrodeposition, alternating two metals to create multilayered nanowires with diameters down to 30 nm and layers perpendicular to the wire axis, so that current flows across the layers. The multilayered nanowires, with 5–10 nm layers, show giant magnetoresistance of 14 % for Co/Cu and 10 % for (Fe,Ni)/Cu at room temperature.

Abstract

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 electrodeposition, an assembly of wires with diameters as low as 30 nm could be obtained. Alternating the electrodeposition of two metals resulted in multilayers grown perpendicular to the wire axis. Layer thicknesses as low as 2 nm could be reached. Application is demonstrated by making wires 6 μm 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 current was naturally perpendicular to the layers. At ambient temperature, a magnetoresistance of 14% for Co/Cu and of 10% for (Fe,Ni)/Cu was observed.