CoCu granular films of thickness 420 to 680 nm are deposited on glass substrates by ion beam deposition technique. Films show a Co/Cu (111) preferred crystallographic orientation which decreases with increasing Cu-concentration. The crystallite size varies between 12 and 24 nm depending on the composition of the film and the heat treatment (300°C/0.5 h), in vacuum and oxygen atmosphere. Vacuum-treated films show lower preferred crystallographic orientation compared to oxygen-treated films. The as-deposited Co 30 Cu 70 film shows lower values of M r /M s , where M r and M s are the remanent and saturation magnetizations respectively, indicating the presence of strong antiferromagnetic coupling and giant magnetoresistance.