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MA: Fachverband Magnetismus

MA 20: Poster I

MA 20.39: Poster

Tuesday, March 19, 2024, 16:30–19:00, Poster A

Ultrathin Fe and Fe3O4 all-oxide heterostructures: Insights from XPS and MOKE — •Andreas Fuhrberg, Pia Maria Düring, Seema Seema, and Martina Müller — FB Physik - Universität Konstanz, 78464 Konstanz, Deutschland

The interface between two different oxide materials can exhibit emerging properties which may be used in novel oxide electronic devices. In particular, interfaces of 3d transition metal oxides show interesting properties like e.g. confined conductivity, magnetism or ferroelectricity. This work focuses on the interface of the 3d ferromagnetic metal Fe and its oxide Fe3O4 with SrTiO3 (STO). Ultrathin films of Fe with varying thicknesses are deposited on STO (001) substrates by molecular beam epitaxy (MBE) at different temperatures. Using lab- and synchrotron-based x-ray photoelectron spectroscopy (XPS), the chemical properties of the interface with STO are explored and a strongly T-dependent interfacial redox reaction is found.

In-operando hard x-ray photoelectron spectroscopy on MBE-grown Fe3O4 thin films on STO:Nb reveals voltage-dependent changes of the core levels and non-ohmic resistance characteristics.

The magnetic properties of Fe3O4/STO:Nb films with varying oxide thickness are studied using magneto-optic Kerr microscopy (MOKE). Influences originating from the diamagnetic substrate and a shift of the magnetic axes caused by anti-phase boundaries are observed.

Keywords: Magneto-optic Kerr effect; Kerr microscopy; Magnetite Fe3O4; HAXPES; Oxide interfaces