Atomic insight into spin, charge and lattice modulations at SrFeO3−x/SrTiO3 interfaces

Abstract

Novel phenomena and functionalities at interfaces of oxide heterostructures are currently of great interest in a wide range of applications. At such interfaces, charge, spin, orbital and lattice ordering coexist and correlate closely, contributing to rich functional responses. By using atomically resolved imaging and spectroscopy techniques, we investigated magnetic behaviors and structural modulation at the SrFeO_3−x/SrTiO₃ interface. Fe/Ti element intermixing and oxygen vacancies occurred across a few unit cells at the interface. Furthermore, antiferromagnetic spin ordering of Fe with different valence states in the interface of SrFeO_3−x/SrTiO₃ induced uncompensated magnetic moments. Compared to the SrFeO_3−x/La_0.3Sr_0.7Al_0.65Ta_0.35O₃ heterojunction, the variations of charge and lattice order parameters at the SrFeO_3−x/SrTiO₃ interfaces were also determined by advanced electron microscopy, which provided a good understanding of the physical origin of disparate macroscopic magnetic properties, further investigated by magnetometer measurements and X-ray magnetic circular dichroism (XMCD) spectra. These studies provide comprehensive insight into the interfacial modulation of ferrite oxide, which may be useful for designing future devices in oxide electronics.