Structural characterization of periodic arrays of magnetic dots

We have investigated the structure and regularity of macroscopically large arrays of submicron magnetic Au/Co/Au dots, which were prepared by combining electron beam lithography, molecular beam epitaxy, and lift-off techniques. Atomic force microscopy was used to characterize the surface roughness of the dots and to show the reproducibility of dot size and periodicity over large areas; low-angle x-ray diffuse scattering experiments were employed to construct a mapping of the reciprocal space in the vicinity of the (000) reflection of the dots. The reciprocal space mapping thus provides information about the internal structure of the dots, as well as about the lateral periodicity of the dot array. This work underlines the important complementarity of scanning probe and x-ray diffraction techniques for the detailed characterization of patterned structures. We observed that the x-ray diffraction patterns are extremely sensitive to the orientation of the dot lattice with respect to the incoming x-ray beam, allowing a quantitative analysis of the lateral periodicity of the dot array and the size of the individual dots.