Anisotropy and interface structure in sputtered Co/Pt multilayers on Si

The inter-relation between magnetic and structural properties of a series of Co/Pt sputtered multilayer films of constant period but differing number of repeats has been investigated. Independent measurements of the perpendicular anisotropy using vibrating sample, alternating gradient field and torque magnetometry were in excellent agreement. Previous measurements showing a large increase in effective anisotropy at about 15 bilayers were confirmed. Low and high angle X-ray scattering showed that the roughness of the interfaces was correlated in all samples and that the interfaces were sharp with no detectable interdiffusion. No systematic trends in roughness, in-plane correlation length or crystallographic texture could be detected with increasing bilayer repeat. The samples with higher perpendicular anisotropy had both lower Co and Pt thickness than the other samples, although this enhancement does not seem to be associated with the thickness variation. The interfaces in these samples had a fractal parameter h of unity, compared with 0.5 for the other samples