Electrodeposition method has allowed the preparation of submicron CoPt particles covered with CoNi shells of different thicknesses The magnetic properties of these particles have been analysed a contribution of semi-hard magnetic behaviour and soft-magnetic behaviour associated with the particles and the CoNi shell respectively has been detected Although a gradual decrease of the coercivity was observed by increasing the CoNi shell thickness the CoPt core always dominates the magnetization-magnetic field curve shape (C) 2010 Elsevier B V All rights reserved