Dependence of the perpendicular anisotropy in Co/Au multilayers on the number of repetitions

The correlations between structure and magnetism in [Co(0.9 nm)/Au(5 nm)]×N multilayer films with different number of repetitions N=10, 30, and 50, have been studied by the combined use of complementary structural and magnetic techniques, such as x-ray reflectivity, x-ray diffraction, and transmission electron microscopy, alternating gradient force magnetometry, magnetic force microscopy and Brillouin light scattering. On increasing the value of N, an overall improvement of the multilayer quality is observed which corresponds to a change in the micromagnetic structure and to an enhancement of the perpendicular anisotropy. These effects have been attributed to a reduction of the magnetostatic energy associated with the formation of perpendicular magnetic domains in multilayers with increasing number of layers repetitions.