The magneto-optical properties of Au-CoxFe3-xO4 core shell nanowires embedded in porous alumina membranes are studied. The structures were obtained by depositing CoxFe3-xO4 on the pore walls of alumina membranes by atomic layer deposition and filling the resulting nanotube with gold by electrodeposition. The effect of plasmon resonance excitation on the magneto-optical activity is clearly observed as a modification of the spectral line shape of the Kerr rotation signal.