Tuning magnetic anisotropy by interfacially engineering the oxygen coordination environment in a transition metal oxide

Abstract

Strong correlations between electrons, spins and lattices--stemming from strong hybridization between transition metal d and oxygen p orbitals--are responsible for the functional properties of transition metal oxides. Artificial oxide heterostructures with chemically abrupt interfaces provide a platform for engineering bonding geometries that lead to emergent phenomena. Here we demonstrate the control of the oxygen coordination environment of the perovskite, SrRuO3, by heterostructuring it with Ca0.5Sr0.5TiO3 (0-4 monolayers thick) grown on a GdScO3 substrate. We found that a Ru-O-Ti bond angle of the SrRuO3 /Ca0.5Sr0.5TiO3 interface can be engineered by layer-by-layer control of the Ca0.5Sr0.5TiO3 layer thickness, and that the engineered Ru-O-Ti bond angle not only stabilizes a Ru-O-Ru bond angle never seen in bulk SrRuO3, but also tunes the magnetic anisotropy in the entire SrRuO3 layer. The results demonstrate that interface engineering of the oxygen coordination environment allows one to control additional degrees of freedom in functional oxide heterostructures.

Interface-induced multiferroism by design in complex oxide superlattices

“…This finding is particularly attractive: because of the chemical bonding, the polar phase usually occurs in nonmagnetic perovskites (30,31,49,50). With recent development of new mechanisms for achieving coexisting ferroelectricity and ferromagnetism (51, 52), our results provide a useful path for how to achieve ferroelectric ferromagnets via interface-induced structural transition in the ultrathin limit (15,16,53,54). We also note that, although controlling interfacial properties via interface octahedral modulation has been a hotly studied subject recently (54-56), our findings push this concept much further by using a structural phase change to realize ultrathin films with unique functional properties.…”

Interfacial orbital preferential occupation induced controllable uniaxial magnetic anisotropy observed in Ni/NiO(110) heterostructures

“…Besides well-investigated exchange bias effect and strain-induced anisotropic magnetism, recently some new interfacial magnetic coupling mechanisms have been proposed in perovskite heterostructures. Z. Liao et al 12 reported an interfacial octahedral coupling caused magnetic anisotropy in manganite epitaxial films and D. Kan et al 30 observed that oxygen coordination environment could dominate the magnetic anisotropy in a SrRuO 3 /Ca 0.5 Sr 0.5 TiO 3 /GaScO 3 (110) heterostructure. Lattice modulation of magnetic anisotropy could be realized by not only tuning the lattice constants and tetragonality.…”

Octahedral Distortions at High‐Temperature Superconducting La2CuO4 Interfaces: Visualizing Jahn–Teller Effects

“…[2][3][4][5] Impressive examples are heterostructure interfaces for which even small alterations of the octahedral network can give rise to striking changes in the electronic structure [6,7] and induce functional properties such as quantum Hall effect, [8] magnetism, [9] superconductivity, [10,11] ferroelectricity, [12] the formation of 2D free electron gases, [13] and hightemperature interfacial superconductivity (HT-IS). [14] During the last years, these interfacial phenomena have attracted more and more attention not only due to potential applications but also due to the fundamental physics and chemistry aspects of these material systems.…”

“…[15] For example, tailoring and tuning lattice distortions can be achieved by strain states imposed, e.g., by the lattice mismatch between substrate and film in epitaxial systems. [3,[16][17][18][19] Thus, understanding how octahedral distortions are correlated with dopant distribution and how they modify the functionality of complex oxide heterostructures is of great significance.The Jahn-Teller (JT) effect is a spontaneous geometric distortion of a nonlinear system in an electronic state with orbital degeneracy and results in removing the degeneracy via energy state splitting and lowering its symmetry. [20] Transition metal oxides with octahedral coordination, in which the metal ion has high-spin d 4 , low-spin d 7 , and d 9 configurations, show JT distortions, which can be intimately correlated with the physical properties.…”

“…[15] For example, tailoring and tuning lattice distortions can be achieved by strain states imposed, e.g., by the lattice mismatch between substrate and film in epitaxial systems. [3,[16][17][18][19] Thus, understanding how octahedral distortions are correlated with dopant distribution and how they modify the functionality of complex oxide heterostructures is of great significance.…”