Effect of interface roughness on magnetic multilayers of Fe/Tb and Fe/Cr

The effect of systematic variation in the correlated interface roughness on perpendicular magnetic anisotropy (PMA) and giant magnetoresistance (GMR) has been studied in Fe/Tb and Fe/Cr multilayer systems, respectively. Multilayers for each system were deposited simultaneously on a set of float glass substrates pretreated with varying rms surface roughness. In both the systems the amount of intermixing at the interfaces and other morphological parameters are found similar, thus allowing one to separate out the effect of interface roughness only. X-ray reflectivity, diffuse scattering, conversion electron Mößbauer spectroscopy and superconducting quantum interference device magnetometry are used to characterise the systems. With the increase in σ, the PMA in Fe/Tb as well as the GMR in Fe/Cr shows a small decrease. The observed effects are mainly due to the changes in the correlated part of the roughness of the multilayers, while the uncorrelated part of the σ of different multilayers are expected to remain similar.