Magnetic Oxide Heterostructures

Abstract

Complex transition metal oxides have played a central role in the study of magnetic materials, serving as model systems for explorations of fundamental exchange interactions and the relationships between structural, electronic, and magnetic responses. Enabled by advances in epitaxial synthesis techniques, abrupt heterointerfaces and superlattices have emerged as a powerful platform for engineering novel magnetic behavior in oxides. Following a brief introduction to the dominant exchange mechanisms in metal oxides, we review the general means by which interfacial magnetism can be tailored in ABO 3 perovskites, including interfacial charge transfer, epitaxial strain and structural coupling, orbital polarizations and reconstructions, and tailoring exchange interactions via cation ordering. Recent examples are provided to illustrate how these strategies have been employed at isolated interfaces and in short-period superlattices. We conclude by briefly discussing underexplored and emerging research directions in the field.

Research Update: Interface-engineered oxygen octahedral tilts in perovskite oxide heterostructures

“…A large displacement of ∼29 pm at the SRO/GSO interface shows that the interfacial octahedral connection consists of the tilted RuO 6 and ScO 6 octahedra. However, the displacement at the BTO/SRO interface is largely suppressed to ∼2 pm, indicating that the RuO 6 octahedra with negligibly small tilts are connected to non-tilted TiO 6 . We ascribed the gradually changing RuO 6 tilts to the difference in the octahedral connection angle between the SRO/GSO and BTO/SRO interfaces.…”

“…[1][2][3][4][5][6][7] Due to recent advances in atomic level synthesis technique, interface engineering [8][9][10][11][12][13] of oxides has emerged as a useful approach to explore and fine tune their functional properties. Because manipulating the interface is often associated with the added structural distortions, it is crucial to understand how the interfacial modification affects not only the structural but also the physical properties of entire constituent oxide layers.…”

Ferromagnetism and matrix-dependent charge transfer in strained LaMnO3–LaCoO3 superlattices

“…They can locally alter the B-site chemical surroundings, such as valence state and B-O-B' bond angles, which essentially govern the magnetic behaviors of the perovskite TMOs and their interfaces [8]. Generally, these extrinsic effects were thought to be inimical to distracting or even concealing the intrinsic properties, which are inevitable to some degree at real interfaces.…”

Fabrication and Ferroelectric Properties of BiFeO3/BaTiO3Heterostructures

“…Several mechanisms are responsible for intrinsic ME effect [1,2]. ME coupling can also occur at FM/FE interfaces where its mechanism is mediated by strain (magnetostriction and piezoelectricity), charge (sensitivity of magnetic state on charge accumulation) or exchange bias (coupling of antiferromagnetic domain walls to ferroelectric ones) [3]. ME effect was also observed in multiferroic tunnel junctions composed of two FM electrodes separated by thin FE barrier [4].…”