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Computer memory based on ferroelectric polarization is a promising alternative to technologies based, for example, on magnetism. Here, Garcia and Bibes review how ferroelectric tunnel junctions, where ferroelectric polarization controls electrical resistance, could improve the performance of these devices.

Refrigeration devices based on giant magnetocaloric materials are hampered by an irreversible caloric effect associated with large magnetic hysteresis. Here, Liu et al. report a multicaloric refrigeration cycle in FeRh thin films coupled to a ferroelectric BaTiO₃substrate, demonstrating reversibility and conversion of hysteretic losses.

The drive to improve digital memory through ever-shrinking electronic circuitry will ultimately face a bottleneck. Researchers propose exploiting the room 'inside' memory elements as a solution.

The room-temperature manipulation of magnetization by an electric field using the multiferroic BiFeO₃ represents an essential step towards the magnetoelectric control of spintronics devices.

Modern technology such as electronics and photovoltaics requires careful control of optical responses of electronic properties. Here, Sando et al. demonstrate a large variation of optical index and light absorption in multiferroic material BiFeO₃thin films, tunable by in-film strain or electric field.

The thin highly conducting electron layer at the interface of LaAlO₃ grown on SrTiO₃ is of promise for nanoscale electronics. Here, the authors show that, by depositing a thin cobalt film on top of LaAlO₃, the minimum thickness of LaAlO₃needed for this conducting layer to form can be reduced to one unit cell.

Superconductivity often emerges at the vicinity of charge and bond-ordered states. Here, by studying ruthenates, the authors demonstrate that it can also be mediated by an electron-phonon coupling related to the proximity of orbital and bond-ordered phases.

Electric-field-induced switching of material’s magnetization is a promising approach for achieving energy-efficient memory devices. By taking advantage of the strong magnetoelectric coupling with a BaTiO₃ substrate, a small electric field is used to switch a FeRh thin film from anti- to ferromagnetic above room temperature.

Materials that simultaneously display ferroelectricity and magnetism, and are metallic, are very rare. Now, the two-dimensional electron gas in an oxide heterostructure brings all of this behaviour together.

Visualization of the Rashbasplit bands in oxide two-dimensional electron gases is lacking, which hampers understanding of their rich spin-orbit physics. Here, the authors investigate KTaO₃ two dimensional electron gases and their Rashba-split bands.

The polarization direction of a ferroelectric-like state can be used to control the conversion of spin currents into charge currents at the surface of strontium titanate, a non-magnetic oxide.

A strong Hall effect is observed in a material with spin textures and strong electron correlations. This hints that correlation effects can amplify real-space topological spin transport.

A very large spin-to-charge conversion arising from a combination of the Rashba effect and topologically non-trivial states is realized at the interface of strontium titanate and aluminium, with implications for the role of topology in memory and transistor designs.

A tunnel junction that consists of a ferroelectric barrier layer sandwiched between two electrodes can operate as a fast, low-power and non-volatile nanoscale solid-state memory.

Memristors are devices whose dynamic properties are of interest because they can mimic the operation of biological synapses. The demonstration that ferroelectric domains in tunnel junctions behave like memristors suggests new approaches for designing neuromorphic circuits.

Induced magnetic ordering at complex oxide interfaces holds potential for spintronic applications. Here, Bruno et al.image the imprinting of domains between ferromagnetic and antiferromagnetic thin films in oxide heterostructures, and demonstrate the effects on tunnelling magnetotransport.

The authors realize voltage-based magnetization switching and reading in nanodevices at room temperature, through exchange coupling between multiferroic BiFeO₃ and ferromagnetic CoFe, for writing, and spin-to-charge current conversion between CoFe and Pt, for reading.

A central goal of spintronics is electric control of magnetism. One particularly promising method makes use of spin-orbit torques which arise due to the combination of electric current, and the intrinsic spin-orbit effect in a material. Here, Grezes et al demonstrate non-volatile electrical control of the spin-orbit torque generated at the interface between an oxide and a metal.

Progress in controlling different ferroic orders such as ferromagnetism and ferroelectricity on the nanoscale could offer unprecedented possibilities for electronic applications.

The electronic properties of oxide interfaces are renowned for their richness. A comprehensive study of a series of perovskite nickelates examines the interplay between charge transfer and hybridization effects.

The Rashba effect at the LaAlO₃/SrTiO₃ interface is shown to enable large and gate-tunable spin-to-charge conversion through the inverse Rashba–Edelstein effect.The spin current is injected, through spin pumping, from a NiFe film.

The ferroelectric properties of BiFeO₃ have been the subject of extensive study. Using a range of experimental tools and numerical modelling, it is now shown that its ferroic properties can also be manipulated by strain effects, giving rise to a variety of magnonic phenomena.

With only a few known useful room-temperature multiferroics, other ways of achieving materials showing magnetism as well as electrical polarization are sought. The discovery that the ferroelectric BaTiO₃ also shows magnetism at room temperature at the interface with iron or cobalt marks a new approach to achieving multiferroic properties.

Accurate modelling of memristor dynamics is essential for the development of autonomous learning in artificial neural networks. Through a combined theoretical and experimental study of the polarization switching process in ferroelectric memristors, Boynet al. establish a model that enables learning and retrieving patterns in a neural system.

The ferroelectric polarization of epitaxial thin films of germanium telluride can be switched by electrical gating and used to control spin-to-charge conversion.

The anomalous Hall effect (AHE) occurs in ferromagnets caused by intrinsic and extrinsic mechanisms. Here, Yoo et al. report large anomalous Hall conductivity and Hall angle at the interface between a ferromagnet La_0.7Sr_0.3MnO₃ and a semimetallic SrIrO₃, due to the interplay between correlated physics and topological phenomena.

As alternative technologies for non-volatile memory elements are looked at, the utilization of ferroelectric layers to read-write upon is seen as promising. However, it is plagued by several problems, including a destructive readout process. Now, by using a thin layer of BaTiO₃ put under intense strain, it has been shown possible to read out the polarization state of the material without destroying it.

It is often stated that first principles studies of transition metal oxides require dynamically correlated methods to correctly produce gap formation, magnetism and structural distortions. Varignon et al. show instead that static correlations are sufficient to capture these features in the ABO₃ oxide series.

The variety of emergent phenomena occurring at oxide interfaces has made these systems the focus of intense study in recent years. We argue that spin–orbit effects in oxide interfaces provide a versatile handle to generate, control and convert spin currents, with a view towards low-power spintronics.

Spin–orbit coupling can be leveraged to enable new functional properties in oxide materials, in particular, for spintronics applications. This Review surveys significant recent advances in the field of oxide spin-orbitronics and discusses its future perspectives.

Chiral electric and magnetic structures are observed at ___domain walls in thin films of the room-temperature multiferroic BiFeO₃.

The electronic properties of complex oxide heterostructures are governed by the physics at the interface between the different materials. Here, the authors use infrared ellipsometry and confocal Raman spectroscopy to show the presence of non-collinear and asymmetric interfacial polar moments in SrTiO₃-based heterostructures underlying the important role of oxygen vacancies in these systems.