THE EFFECT OF MICROSTRUCTURE ON THE MAGNETIC-BEHAVIOR OF EPITAXIAL COBALT LAYERS

We have studied the magnetic behavior of thin cobalt films epitaxed on a Cu (001) substrate as a function of their growth temperature. At 150 K, the film texture is rough and the surface coverage is incomplete for film thicknesses < 1.2 monolayers. Smoother films are obtained as the substrate temperature is increased, but at the expense of increased copper interdiffusion. Growth of films at 450 K produces smooth continuous epitaxial layers but coated with a layer of interdiffused copper which serves to lower the surface free energy. Copper interdiffusion can be controlled at intermediate temperatures between 300 and 450 K. We report on the effect of annealing cycles on the microstructure of these films in relation to their magnetic properties, as revealed by surface magneto-optic Kerr effect hysteresis loop behavior.