Electrodeposition and room temperature ferromagnetic anisotropy of Co and Ni-doped ZnO nanowire arrays

Abstract

Cobalt and nickel doped ZnO nanowire arrays were synthesized by an electrochemical process at a temperature of 90°C. Energy dispersive x-ray spectroscopy and x-ray diffraction show that the dopants are incorporated into the wurtzite-structure ZnO. Anisotropic ferromagnetism with an easy direction of magnetization either perpendicular or parallel to the wire axis, depending on the wire geometry and density, was observed in 1.7% Co and 2.2% Ni-doped ZnO nanowires at room temperature. The anisotropic magnetism was explained in terms of a competition between self-demagnetization and magnetostatic coupling among the nanowires.