  Search for ultrathin magnetic film with large perpendicular
magnetocrystalline anisotropy (PMA) has been inspired for years by the
continuous miniaturization of magnetic units in spintronics devices. The common
magnetic materials used in research and applications are based on Fe because
the pure Fe metal is the best yet simple magnetic material from nature. Through
systematic first-principles calculations, we explored the possibility to
produce large PMA with ultrathin Fe on non-noble and non-magnetic Pb(001)
substrate. Interestingly, huge magnetocrystalline anisotropy energy (MAE) of
7.6 meV was found in Pb/Fe/Pb(001) sandwich structure with only half monolayer
Fe. Analysis of electronic structures reveals that the magnetic proximity
effect at the interface is responsible for this significant enhancement of MAE.
The MAE further increases to 13.6 meV with triply repeated capping Pb and
intermediate Fe layers. Furthermore, the MAE can be tuned conveniently by
charge injection.
