The influence of surface roughness in X-ray resonant magnetic reflectivity experiments

We present simulations of X-ray resonant magnetic reflectivity(XRMR) spectra of the surface magnetic dead layer inLa1−xSrxMnO3 (LSMO) films that take in account the effect of differentforms of roughness that can be encountered experimentally. Theresults demonstrate a method to distinguish between surface (morphological)roughness, and two generic kinds of magnetic roughness at theburied interface between the surface dead layer and the fully magneticbulk part of the film. We show that the XRMR technique can distinguishbetween different types of magnetic roughness at the deadlayer/bulk interface only if the sample surface is nearly atomically flat(the morphological roughness is one unit cell or less). Furthermore, todistinguish between the two types of magnetic roughness, the simulationsshow that fitting of XRMR spectra out to very high incidenceangles must be performed. In the specific case of LSMO films with adead layer with average thickness of 4 unit cells, this corresponds to anincidence angle >50◦.