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 similar to 260 nm Co core nanorods surrounded by similar to 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.