Growth of a crystalline and ultrathin MgO film on Fe(001)

The narrow temperature-window for obtaining a crystalline MgO film on Fe(001) has been found using in-situ STM. When Mg was deposited on Fe(001) at RT, post-oxidized at 300 °C, and additionally annealed at 400 °C, an ultrathin and crystalline MgO film was formed. It has been concluded that, in order to grow a high-quality and crystalline MgO film on Fe(001), it requires two steps, i.e., Mg film formation on the substrate at RT and subsequent annealing at the proper substrate temperature under O2 exposure for Mg atoms to be oxidized and crystallized at their deposited sites without being agglomerated.