Magnetic CoFe2O4 films with controllable dendritic arrays by a combined method of electrodeposition and anode activation

Abstract

Cobalt ferrite (CoFe₂O₄, CFO) films with dendritic arrays were prepared on Pt/TiO₂/SiO₂/Si substrates using a combined electrochemical method of electrodeposition and anode activation. First, the CoFe₂ (CF) alloy films were electrodeposited from a solution of Fe₂SO₄ and Co₂SO₄ at room temperature. Then, CFO films were prepared by anode-activating and annealing the alloy films. Effects of preparation conditions on the crystalline structure, microtopography and magnetic properties of CFO films were investigated. Interestingly, different from the reported results, smooth CFO films were obtained after annealing CF films in air, even without anodization, while controllable dendritic arrays of CFO were observed after anode-activating and annealing processes. Anodization was not necessary to form the CFO films, but had an important effect on the morphology of the CFO films, and CFO films with desirable dendritic morphology could be formed by controlling anode activation process parameters.