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Materials with strong spin-orbit coupling (SOC) have been continuously attracting intensive attention due to their promising application in energy-efficient, high-density, and nonvolatile spintronic devices. Particularly, transition-metal perovskite oxides with strong SOC have been demonstrated to exhibit efficient charge-spin interconversion. In this study, we systematically investigated the impact of epitaxial strain on the spin-orbit torque (SOT) efficiency in the SrIrO 3 (SIO)/Ni 81 Fe 19 (Py) bilayer. The results reveal that the SOT efficiency is strongly related to the octahedral rotation around the in-plane axes of the single-crystal SIO. By modulating the epitaxial strain using different substrates, the SOT efficiency can be remarkably improved from 0.15 to 1.45. This 10-fold enhancement of SOT efficiency suggests that modulating the epitaxial strain is an efficient approach to control the SOT efficiency in complex oxide-based heterostructures. Our work may have the potential to advance the application of complex oxides in energy-efficient spintronic devices.

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 /SrTiO 3 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 /SrTiO 3 induced uncompensated magnetic moments. Compared to the SrFeO 3-x /La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 heterojunction, the variations of charge and lattice order parameters at the SrFeO 3-x /SrTiO 3 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.

Interfaces between materials provide an intellectually rich arena for fundamental scientific discovery and device design. However, the frustration of magnetization and conductivity of perovskite oxide films under reduced dimensionality is detrimental to their device performance, preventing their active low-dimensional application. Herein, by inserting the ultrathin 4d ferromagnetic SrRuO 3 layer between ferroelectric BaTiO 3 layers to form a sandwich heterostructure, we observe enhanced physical properties in ultrathin SrRuO 3 films, including longitudinal conductivity, Curie temperature, and saturated magnetic moment. Especially, the saturated magnetization can be enhanced to ∼3.12 μ B /Ru in ultrathin BaTiO 3 /SrRuO 3 /BaTiO 3 trilayers, which is beyond the theoretical limit of bulk value (2 μ B /Ru). This observation is attributed to the synergistic ferroelectric proximity effect (SFPE) at upper and lower BaTiO 3 /SrRuO 3 heterointerfaces, as revealed by the high-resolution lattice structure analysis. This SFPE in dual-ferroelectric interface cooperatively induces ferroelectric-like lattice distortions in RuO 6 oxygen octahedra and subsequent spin-state crossover in SrRuO 3 , which in turn accounts for the observed enhanced magnetization. Besides the fundamental significance of interface-induced spin-lattice coupling, our findings also provide a viable route to the electrical control of magnetic ordering, taking a step toward low-power applications in all-oxide spintronics.