Magnetic properties of ultra-thin Mn films grown on (001) BCCFe

The structural and magnetic properties of ultra-thin Mn films epitaxially g rown on (0 0 1) Fe are investigated by X-ray absorption and magnetic circul ar dichroism. On the one hand, Mn is observed to grow in a BCT structure up to 2 atomic planes. A ferromagnetic order within the Mn layer and a ferrom agnetic Mn/Fe coupling are observed. Above 2 monolayers, the Mn structure c hanges and the ferromagnetic order disappears. However, this structural tra nsition is due to the increase of the Mn film dimension from 2D to 3D, but not due to the structural transition. On the other hand, the magnetic prope rties below 2 monolayers are observed to drastically change when the Mn fil ms are oxidized. The Mn/Fe coupling observed to be ferromagnetic in unoxidi zed Mn films becomes antiferromagnetic when the Mn film is oxidized. (C) 19 99 Elsevier Science B.V. All rights reserved.