Fabrication and magnetic properties of CoxCu1-x composite nanowire arrays

Abstract

A series of composite structured CoxCu1-x(x=0.38—0.87) nanowire arrays have been successfully deposited in the same Co2+/Cu2+=10∶1 solution by applying various depositing potentials. We found that the structures of CoxCu1-x composite nanowires regularly changed with increase of Cu content, thus causing regular change of the magnetic properties of CoCu nanowires. With the percent content of Cu increasing, part of Cu and Co form metastable face-centred cubic (fcc) CoCu solid solution which decreases the competition between the crystallographic anisotropy and shape anisotropy and improves the squareness of CoCu nanowires; the remaining part of Cu exists in the nanowires as fcc Cu crystals which destroy the crystallographic anisotropy and increases the pinning of domain walls, thus improves the squareness and coercivity of CoCu nanowires. Comparing CoxCu1-x nanowires of different compositions, we found that the nanowires have their maximum of the squareness (Mr/Ms) and coercivity (Hc) values for Co75Cu25 and Co60Cu40, respectively. Because of the special composite structures, the values exceed those of single phase CoCu nanowire with the same diameter.