Microstructure and magnetic behavior of electrodeposited CoPt thick films upon annealing

CoPt films with a thickness about 5-μm consisting of a disordered face-centered cubic phase have been prepared by using the electrodeposition technique. X-ray diffraction measurements and transmission electron microscopy studies reveal that the annealed CoPt films possess a nanocomposite microstructure of A1 + L10 CoPt and the size and volume fraction of the L10 ordered phase increase with annealing time. A strong magnetic exchange coupling between the A1 phase and the L10 ordered phase is observed after annealing for 2.5 h, which yields a large coercivity Hc = 14.2 kOe and a high remanence ratio Mr/Ms = 0.88 for the nanocomposite thick films of A1 + L10 CoPt.