Electrochemical preparation and magnetic properties of submicrometric core–shell CoPt–CoNi particles

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.