Electrochemical preparation and characterisation of CoPt magnetic particles

CoPt particles of different size and modulate magnetic properties have been prepared by electrodeposition. Particles of growing size from 50 nm until continuous deposits have been obtained and their composition, crystalline structure and magnetic properties have been analyzed. The prepared CoPt particles from 50 nm to 250 nm showed ferromagnetic behaviour so did the continuous deposits. However, drastic changes in magnetism have been detected related to the size of the particles: the smallest particles presented lower coercivity which increases with increasing size, with a maximum value for particles of 150–250 nm diameter. The coercivity decreased when continuous deposits were attained due to the disordered growing and the loss of the surface anisotropy.