X-Ray absorption and reflectivity studies of MnF2 initial growth on CaF2/Si(111)

MnF2/CaF2/Si(111) triple layer was grown and studied by RHEED, AFM, X-ray reflectivity and absorption at Mn 2p, Ca 2p, Si 2p, F 1s edges. It was observed that the CaF2 lattice orientation on Si(111) drives the growth mode of MnF2. In particular experimental results indicate that at the first deposition stages, up to 3 monolayers, the MnF2 film keeps the cubic lattice structure of the CaF2 buffer. This changes to -PbO2 type structure at higher coverage. The fact that MnF2 inherits the lattice structure of CaF2 could explain the x-ray absorption line shape at F 1s edge. On the other hand, Mn 2p absorption edges do not show at the low coverage investigated here the features characteristic of bulk MnF2 and due to crystal field splitting.