STRUCTURE AND MAGNETISM OF MN RU AND MN/FE/MN/RU SUPERLATTICES PREPARED BY MOLECULAR-BEAM EPITAXY/

Our recent study on Fe/Ru superlattices revealed a hexagonal structure , a reduced magnetic moment (1.7 muB) in the plane of the layers, and an antiferromagnetic coupling between the Fe mediated through Ru. We i nserted just one plane of manganese between the Fe and the Ru to deter mine the interface influence on the structural and magnetic properties in Mn/Fe/Mn/Ru superlattices by means of local and selective techniqu es such as x-ray-absorption and Mossbauer spectroscopy. We describe th e growth of Mn on Ru by reflection high-energy electron diffraction an d by Auger electron microscopy experiments to realize the superlattice s Mn/Ru. Complementary results obtained from x-ray-diffraction and mac roscopic magnetization measurements allowed us to quantitatively descr ibe our systems. The Mn structure was found to be identical to the Fe structure in Fe/Ru superlattices. We show that there is no solid solut ion between Fe and Ru at the interface in Fe/Ru which could be respons ible for the four Fe magnetically inactive layers. We obtain the same reduced magnetic moment for the next Fe layer and a moment of few tent hs of muB for a Mn layer. Finally we confirm once more the excellent q uality of the interface in these superlattices which did not give gian t magnetoresistance.