The Giant Magnetoresistance (GMR) observed in magnetic multilayers is
due to spin-dependent scattering of electrons at interfaces or bulk de
fects. In order to unambiguously separate these two possible contribut
ions, we produced Fe/Cr superlattices with negligible bulk defects, th
us providing only interface scattering. The vertical and lateral inter
face roughness parameters were quantitatively analysed using synchrotr
on X-ray diffraction and Conversion Electron Mossbauer Spectroscopy. T
he magnitude of the GMR effect depends on both the vertical roughness
amplitude eta and the step density n(step). We find a linear increase
of the Giant Magnetoresistance with eta x n(step).