Enhanced non-classical electrostriction in strained tetragonal ceria.

Electrostriction is the upsurge of strain under an electric field in any dielectric material. Oxygen-defective metal oxides, such as acceptor-doped ceria, exhibit high electrostriction 10 mV values, which can be further enhanced via interface engineering at the nanoscale. This effect in ceria is "non-classical" as it arises from an intricate relation between defect-induced polarisation and local elastic distortion in the lattice.

On the effect of precession for magnetic differential phase contrast imaging.

The separation of diffraction effects from phase contrast is a major challenge for differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). The application of electron beam precession has previously been proven successful in homogenizing the direct beam and improving the imaging of both long-range electric and magnetic fields. However, magnetic STEM-DPC imaging performed in a low magnification (LM) STEM mode suffers from significant aberrations of the probe forming lens and the consequent impediment of small precession angles.

The fabrication of freestanding complex oxide membranes: Can we avoid using water?

Unlabelled: Recent advances in fabricating scalable two-dimensional or freestanding functional materials have shown promise for their use in modern silicon-based electronics and future technologies. A growing interest is in creating freestanding complex oxide membranes using new methods like epitaxial lift-off and mechanical exfoliation to enhance their quality and integrity. Despite these advances, it remains challenging to consistently produce high-quality freestanding oxide membranes on a large scale for practical use.

The Role of Interface Band Alignment in Epitaxial SrTiO/GaAs Heterojunctions.

Correlated oxides are known to have remarkable properties, with a range of electronic, magnetic, optoelectronic, and photonic functionalities. A key ingredient in realizing these properties into practical technology is the effective and scalable integration of oxides with conventional semiconductors. Unlocking the full spectrum of functionality requires atomically abrupt oxide-semiconductor interfaces and intimate knowledge of their potential landscape and charge transport.

Extreme magnetoresistance at high-mobility oxide heterointerfaces with dynamic defect tunability.

Magnetic field-induced changes in the electrical resistance of materials reveal insights into the fundamental properties governing their electronic and magnetic behavior. Various classes of magnetoresistance have been realized, including giant, colossal, and extraordinary magnetoresistance, each with distinct physical origins. In recent years, extreme magnetoresistance (XMR) has been observed in topological and non-topological materials displaying a non-saturating magnetoresistance reaching 10-10% in magnetic fields up to 60 T.

Strain Engineering: Perfecting Freestanding Perovskite Oxide Fabrication.

Freestanding oxide membranes provide a promising path for integrating devices on silicon and flexible platforms. To ensure optimal device performance, these membranes must be of high crystal quality, stoichiometric, and their morphology free from cracks and wrinkles. Often, layers transferred on substrates show wrinkles and cracks due to a lattice relaxation from an epitaxial mismatch.

Post-lithiation: a way to control the ionic conductivity of solid-state thin film electrolyte.

Ionic conductivity is pivotal for solid-state battery performance. While the garnet oxide electrolyte LiLaZrO (LLZO) boasts high ionic conductivity due to its distinct crystal structure and lithium-ion mobility, lithium loss during fabrication hampers its potential. In this study, we introduce a method that merges synthesis optimization with a post-lithiation process, enhancing LLZO's ionic conductivity.

Controlled Electronic and Magnetic Landscape in Self-Assembled Complex Oxide Heterostructures.

Complex oxide heterointerfaces contain a rich playground of novel physical properties and functionalities, which give rise to emerging technologies. Among designing and controlling the functional properties of complex oxide film heterostructures, vertically aligned nanostructure (VAN) films using a self-assembling bottom-up deposition method presents great promise in terms of structural flexibility and property tunability. Here, the bottom-up self-assembly is extended to a new approach using a mixture containing a 2Dlayer-by-layer film growth, followed by a 3D VAN film growth.

Atomically engineered interfaces yield extraordinary electrostriction.

Electrostriction is a property of dielectric materials whereby an applied electric field induces a mechanical deformation proportional to the square of that field. The magnitude of the effect is usually minuscule (<10 m V for simple oxides). However, symmetry-breaking phenomena at the interfaces can offer an efficient strategy for the design of new properties.

Stacking and Twisting of Freestanding Complex Oxide Thin Films.

The integration of dissimilar materials in heterostructures has long been a cornerstone of modern materials science-seminal examples are 2D materials and van der Waals heterostructures. Recently, new methods have been developed that enable the realization of ultrathin freestanding oxide films approaching the 2D limit. Oxides offer new degrees of freedom, due to the strong electronic interactions, especially the 3d orbital electrons, which give rise to rich exotic phases.

A Two-Dimensional Superconducting Electron Gas in Freestanding LaAlO/SrTiO Micromembranes.

Freestanding oxide membranes constitute an intriguing material platform for new functionalities and allow integration of oxide electronics with technologically important platforms such as silicon. Sambri et al. recently reported a method to fabricate freestanding LaAlO/SrTiO (LAO/STO) membranes by spalling of strained heterostructures.

Robust Electronic Structure of Manganite-Buffered Oxide Interfaces with Extreme Mobility Enhancement.

The electronic structure as well as the mechanism underlying the high-mobility two-dimensional electron gases (2DEGs) at complex oxide interfaces remain elusive. Herein, using soft X-ray angle-resolved photoemission spectroscopy (ARPES), we present the band dispersion of metallic states at buffered LaAlO/SrTiO (LAO/STO) heterointerfaces where a single-unit-cell LaMnO (LMO) spacer not only enhances the electron mobility but also renders the electronic structure robust toward X-ray radiation. By tracing the evolution of band dispersion, orbital occupation, and electron-phonon interaction of the interfacial 2DEG, we find unambiguous evidence that the insertion of the LMO buffer strongly suppresses both the formation of oxygen vacancies as well as the electron-phonon interaction on the STO side.

Improved High-Temperature Thermoelectric Properties of Dual-Doped CaCoO.

Layered structured CaCoO has displayed great potential for thermoelectric (TE) renewable energy applications, as it is nontoxic and contains abundantly available constituent elements. In this work, we study the crystal structure and high-temperature TE properties of Ca Na Co Mo O (0 ≤ ≤ 0.10) polycrystalline materials.

Induced giant piezoelectricity in centrosymmetric oxides.

Piezoelectrics are materials that linearly deform in response to an applied electric field. As a fundamental prerequisite, piezoelectric materials must have a noncentrosymmetric crystal structure. For more than a century, this has remained a major obstacle for finding piezoelectric materials.

On the thermoelectric properties of Nb-doped SrTiO epitaxial thin films.

The exploration for thermoelectric thin films of complex oxides such as SrTiO-based oxides is driven by the need for miniaturized harvesting devices for powering the Internet of Things (IoT). However, there is still not a clear consensus in the literature for the underlying influence of film thickness on thermoelectric properties. Here, we report the fabrication of epitaxial thin films of 6% Nb-doped SrTiO on (001) (LaAlO)(SrAlTaO) (LSAT) single crystal using pulsed laser deposition (PLD) where the film thickness was varied from 2 nm to 68 nm.

BaBiCoRuO (0.0 ≤ ≤ 0.6) Hexagonal Double-Perovskite-Type Oxides as Promising p-Type Thermoelectric Materials.

A new series of BaBiCoRuO (0.0 ≤ ≤ 0.6) hexagonal double perovskite oxides have been synthesized by a solid-state reaction method by substituting Ba with Bi.

Band-Order Anomaly at the γ-AlO/SrTiO Interface Drives the Electron-Mobility Boost.

The rich functionalities of transition-metal oxides and their interfaces bear an enormous technological potential. Its realization in practical devices requires, however, a significant improvement of yet relatively low electron mobility in oxide materials. Recently, a mobility boost of about 2 orders of magnitude has been demonstrated at the spinel-perovskite γ-AlO/SrTiO interface compared to the paradigm perovskite-perovskite LaAlO/SrTiO interface.

Time-Enhanced Performance of Oxide Thermoelectric Modules Based on a Hybrid p-n Junction.

The present challenge with all-oxide thermoelectric modules is their poor durability at high temperatures caused by the instability of the metal-oxide interfaces at the hot side. This work explains a new module concept based on a hybrid p-n junction, fabricated in one step by spark plasma co-sintering of CaCo O (CCO, p-type) and CaMnO/CaMnO (CMO, n-type). Different module (unicouple) designs were studied to obtain a thorough understanding of the role of the formed hybrid p-n junction of CaCoMnO (CCMO, p-type) and Co-oxide rich phases (p-type) at the p-n junction (>700 °C) in the module performance.

Atomic-scale insights into electro-steric substitutional chemistry of cerium oxide.

Cerium oxide (ceria, CeO2) is one of the most promising mixed ionic and electronic conducting materials. Previous atomistic analysis has widely covered the effects of substitution on oxygen vacancy migration. However, an in-depth analysis of the role of cation substitution beyond trivalent cations has rarely been explored.

The emergence of magnetic ordering at complex oxide interfaces tuned by defects.

Complex oxides show extreme sensitivity to structural distortions and defects, and the intricate balance of competing interactions which emerge at atomically defined interfaces may give rise to unexpected physics. In the interfaces of non-magnetic complex oxides, one of the most intriguing properties is the emergence of magnetism which is sensitive to chemical defects. Particularly, it is unclear which defects are responsible for the emergent magnetic interfaces.

Solar-driven plasmonic heterostructure Ti/TiO with gradient doping for sustainable plasmon-enhanced catalysis.

Plasmon-enhanced harvesting of photons has contributed to the photochemical conversion and storage of solar energy. However, high dependence on noble metals and weak coupling in heterostructures constrain the progress towards sustainable plasmonic enhancement. Here earth-abundant Ti is studied to achieve the plasmonic enhancement of catalytic activity in a solar-driven heterostructure Ti/TiO2-x.

On the emergence of conductivity at SrTiO-based oxide interfaces - an in-situ study.

Heterostructures and crystal interfaces play a major role in state-of-the-art semiconductor devices and play a central role in the field of oxide electronics. In oxides the link between the microscopic properties of the interfaces and bulk properties of the resulting heterostructures challenge our fundamental understanding. Insights on the early growth stage of interfaces and its influence on resulting physical properties are scarce - typically the information is inferred from post growth characterization.

Electrical, magnetic and magnetotransport properties of Na and Mo doped CaCoO materials.

We report the electrical, magnetic and magnetotransport properties of Na and Mo dual doped Ca Na Co Mo O (0 ≤ ≤ 0.15) polycrystalline samples. The results indicate that the strength of ferrimagnetic interaction decreases with increase in doping, as is evident from the observed decrease in Curie temperatures ( ).

Surface Pyroelectricity in Cubic SrTiO.

Symmetry-imposed restrictions on the number of available pyroelectric and piezoelectric materials remain a major limitation as 22 out of 32 crystallographic material classes exhibit neither pyroelectricity nor piezoelectricity. Yet, by breaking the lattice symmetry it is possible to circumvent this limitation. Here, using a unique technique for measuring transient currents upon rapid heating, direct experimental evidence is provided that despite the fact that bulk SrTiO is not pyroelectric, the (100) surface of TiO -terminated SrTiO is intrinsically pyroelectric at room temperature.

Electrochemical stability of (La,Sr)CoO in (La,Sr)CoO/(Ce, Gd)O heterostructures.

A modulated coherent (La,Sr)CoO3-δ/(Ce,Gd)O2-δ heterostructure is characterized for the first time for its electronic and chemical properties. 2D-multilayer architectures are deposited on NdGaO3 (110) single crystal substrate by pulsed laser deposition, resulting in epitaxial structures with in-plane lattice rotation that, via the metal oxides' interfaces, induces mutual structural rearrangements. Our results show that (La,Sr)CoO3-d thin films of 10-100 nm are chemically unstable when exposed to air at 600 °C during electrical cyclic stress-tests.