TiO2 as an electrostatic template for epitaxial growth of EuO on MgO(001) by reactive molecular beam epitaxy

We investigate the initial growth modes and the role of interfacial electrostatic interactions of EuO epitaxy on MgO(001) by reactive molecular beam epitaxy. A TiO2 interfacial layer is employed to produce high quality epitaxial growth of EuO on MgO(001) with a 45{\deg} in plane rotation. For comparison, direct deposition of EuO on MgO, without the TiO2 layer shows a much slower time evolution in producing a single crystal film. Conceptual arguments of electrostatic repulsion of like-ions are introduced to explain the increased EuO quality at the interface with the TiO2 layer. It is shown that ultrathin EuO films in the monolayer regime can be produced on the TiO2 surface by substrate-supplied oxidation and that such films have bulk-like magnetic properties.