Unraveling the effect of oxygen on the magnetic map of Fe/Cr multilayers

Recent experimental results have depicted a strong modification of the magnetic map when oxygen is added to Fe/Cr multilayers. Within ab initio DFT + U code we show that the Fe/O/Cr/Fe(001) semi-infinite system is unstable whereas oxygen tends to move on top of the Fe atomic layer. Focuss is therefore made on the O/Fe/Cr/Fe(001) semi-infinite slab which displays an interlayer exchange coupling different from the classical case when O is absent. The effect of the oxygen adsorbed layer is to alter strongly the local density of states on the Fe atoms: this can explain the modification of the interlayer exchange coupling. Both DFT-only and DFT + U approaches are investigated in order to point out the major effect of U on the magnetic polarization