Ordered Ni−Cu Nanowire Array with Enhanced Coercivity

A highly ordered composite Ni−Cu nanowire array has been fabricated within the pores of an anodic aluminum oxide (AAO) template by pulsed electrodeposition, and it has been characterized by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), magnetic force microscopy (MFM), and superconducting quantum-interference device (SQUID) measurements. It was found that all the Ni segments are single magnetic domain and aligned to the same direction after magnetizing under an external field (perpendicular or parallel to the axes of the nanowires). Magnetization measurements on the array revealed a remarkably enhanced coercivity and a similar high-saturation magnetization compared to that of bulk nickel. Owing to its high bit density (up to 70 Gbits/in 2 ), the structure may be suitable for ultrahigh-density magnetic recording media.