Electrochemical synthesis of core-shell Co-Ni nanorod arrays with facilely regulated magnetic properties

Ordered Co-Ni core-shell magnetic nanorod arrays were fabricated by a two-step electrodeposition into a self-assembled anodic alumina oxide template. The characterizations of the morphology and elemental distribution indicated the successful fabrication of ∼260 nm Co core nanorods surrounded by ∼20 nm concentric Ni shell. The magnetization measurement revealed that the synthesized Co-Ni core-shell nanorod arrays exhibited lower coercivity and higher remanence ratio than plain Co nanorod arrays, offering a possibility to regulate suitable coercivity at the nanoscale. It was also demonstrated combing tube and rod to form core-shell structure offered the perspective for engineering the magnetic properties without changing geometric parameters or with minimally altered crystalline structure.