Interlayer Exchange Coupling of Fe/Cr/Fe Thin Films on Rippled Substrates

The influence of rippled vs. flat Si substrates on the interlayer exchange coupling of polycrystalline Fe/Cr/Fe thin films is studied. The rippled substrates with ripple wavelengths of 22 and 37 nm where created by means of ion beam erosion. Using lambda=22 nm ripple substrates we find a Néel coupling superimposed on the interlayer exchange coupling in Fe/Cr/Fe trilayers associated with a strong uniaxial anisotropy induced by the substrate topography. These results are obtained by applying a Stoner-Wolfarth model on magnetic reversal loops obtained via longitudinal magneto-optical Kerr effect magnetometry.