Magnetic-Field-Assisted Molecular Beam Epitaxy: Engineering of Fe3O4 Ultrathin Films on MgO(111)

Molecular beam epitaxy is widely used for engineering low-dimensional materials. Here, we present a novel extension of the capabilities of this method by assisting epitaxial growth with the presence of an external magnetic field (MF). MF-assisted epitaxial growth was implemented under ultra-high vacuum conditions thanks to specialized sample holders for generating in-plane or out-of-plane MF and dedicated manipulator stations with heating and cooling options. The significant impact of MF on the magnetic properties was shown for ultra-thin epitaxial magnetite films grown on MgO(111). Using in situ and ex situ characterization methods, scanning tunneling microscopy, conversion electron Mossbauer spectroscopy, and the magneto-optic Kerr effect, we showed that the in-plane MF applied during the reactive deposition of 10 nm Fe3O4(111)/MgO(111) heterostructures influenced the growth morphology of the magnetite films, which affects both in-plane and out-of-plane characteristics of the magnetization process. The observed changes are explained in terms of modification of the effective magnetic anisotropy.

Automated summary

Molecular beam epitaxy is enhanced by the presence of an external magnetic field, which impacts the growth morphology and magnetic properties of epitaxial magnetite films on MgO(111). In situ and ex situ characterization techniques revealed that the in-plane magnetic field during deposition influenced the film growth and magnetization process, attributed to modification of the effective magnetic anisotropy. This novel approach expands the capabilities of molecular beam epitaxy for engineering low-dimensional materials.