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LaSrCoO4, LaSrNiO4 and LaSrCuO4 were synthesised by the reverse micellar route by using three different microemulsion compositions. The as prepared nanostructures were characterised by powder X‐ray diffraction (PXRD), field emission scanning electron microscopy, energy dispersive X‐ray spectroscopy and transmission electron microscopy. The PXRD of all samples indicate pure phases which crystallize into a tetragonal system. The particle size and shape of nanoparticles varies with microemulsion system. Magnetisation studies suggested that two of the LaSrCoO4 samples display canted antiferromagnetism while the others showed no sign of long‐range ordering. The LaSrNiO4 and LaSrCuO4 samples seemed to show spin glass behaviour. Some of these materials were successfully used as catalysts for organic transformations. The esterification of aldehydes in the presence of alkyl halides and alcohols has been made mild and practicable with a copper catalysed TBHP/DTBP promoting reaction. This approach is suitable to a wide variety of aldehydes, including those that are notoriously difficult to convert through the C(sp2)−H bond scission to produce the required esters in good to outstanding yield. [ABSTRACT FROM AUTHOR]

Acoustically driven ferromagnetic resonance (ADFMR) is a platform that enables efficient generation and detection of spin waves via magnetoelastic coupling with surface acoustic waves (SAWs). While previous studies successfully achieved ADFMR in ferromagnetic metals, there are only few reports on ADFMR in magnetic insulators such as yttrium iron garnet (Y3Fe5O12, YIG) despite more favorable spin wave properties, including low damping and long coherence length. The growth of high-quality YIG films for ADFMR devices is a major challenge due to poor lattice-matching and thermal degradation of the piezoelectric substrates during film crystallization. In this work, we demonstrate ADFMR of YIG thin films on LiNbO3 (LNO) substrates. We employed a SiOx buffer layer and rapid thermal annealing for crystallization of YIG films with minimal thermal degradation of LNO substrates. Optimized ADFMR device designs and time-gating measurements were used to enhance the ADFMR signal and overcome the intrinsically low magnetoelastic coupling of YIG. YIG films have a polycrystalline structure with an in-plane easy direction due to biaxial stresses induced during cooling after crystallization. The YIG device shows clear ADFMR patterns with maximum absorption for H ≈ 160 mT parallel to SAW propagation, which is consistent with our simulation results based on existing theoretical models. These results expand possibilities for developing efficient spin wave devices with magnetic insulators. [ABSTRACT FROM AUTHOR]

Magnetoelectric oxide heterostructures are proposed active layers for spintronic memory and logic devices, where information is conveyed through spin transport in the solid state. Incomplete theories of the coupling between local strain, charge, and magnetic order have limited their deployment into new information and communication technologies. In this study, we report direct, local measurements of strain- and charge-mediated magnetization changes in the La0.7Sr0.3MnO3/PbZr0.2Ti0.8O3 system using spatially resolved characterization techniques in both real and reciprocal space. Polarized neutron reflectometry reveals a graded magnetization that results from both local structural distortions and interfacial screening of bound surface charge from the adjacent ferroelectric. Density functional theory calculations support the experimental observation that strain locally suppresses the magnetization through a change in the Mn-eg orbital polarization. We suggest that this local coupling and magnetization suppression may be tuned by controlling the manganite and ferroelectric layer thicknesses, with direct implications for device applications.

Characterizing resin extent of cure kinetics is critical to understanding the structure–property-processing relationships of polymers. The disorder band present in the low-frequency region of the Raman spectrum is directly related to conformational entropy and the modulus of amorphous materials, both of which change as the resin polymerizes. Normalizing the disorder band to its shoulder (∼85 cm−1) provides structural conversion kinetics, which we can directly correlate to chemical conversion kinetics for methacrylate and epoxy–amine based resin systems. In addition to fitting both the structural and chemical conversion data to a phenomenological kinetic rate equation, we also demonstrate a relationship between the chemical and structural kinetics which appears to relate to the softness of the material. Lastly, we use the method to investigate a methacrylate/epoxy interpenetrating polymer network resin system. We find that the structural and chemical conversions occur simultaneously during the formation of the primary (methacrylate) network, but there is a lag between the two during the formation of the secondary (epoxy–amine) network. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate photocatalytic hydrogen generation and the role of sacrificial agents using multi‐functional DyCrO3 nanoparticles by virtue of built‐in electric field (BIEF) which helps in increasing charge separation efficiency. DyCrO3 nanoparticles synthesized by the low‐cost reverse micellar approach showed high surface area (17.9 m2/g) and band‐gap (2.01 eV) in visible region. Sacrificial agent assisted photocatalytic H2 production of DyCrO3 nanoparticles exhibited higher selectivity towards Na2S/Na2SO3 by producing H2 evolution of 347 μmolh-1gcat-1 ${mol\ {h}^{-1}{g}_{cat}^{-1}{\rm \ }}$ and apparent quantum yield of 6.8% than ethylene glycol and triethanolamine, respectively. The oxygen defects (observed in X‐ray photoelectron spectroscopic studies) and BIEF both synergistically helped in enhancing photocatalytic activity. Moreover, the multifunctional competence of DyCrO3 nanoparticles was observed in electrocatalytic water splitting. DyCrO3 nanoparticles found to be active HER and OER electrocatalyst with low overpotential and great durability. [ABSTRACT FROM AUTHOR]

Glass transition temperature is one of the most important characteristics to describe the behavior of polymeric materials. When a material goes through glass transition, conformational entropy increases, which affects the phonon density of states. Amorphous materials invariably display low-frequency Raman features related to the phonon density of states resulting in a broad disorder band below 100 cm−1. This band includes the Boson peak and a shoulder, which is dominated by the van Hove peak, and quasi-elastic Rayleigh scattering also contributes to the signal. The temperature dependence of the ratio of the integrated intensity in proximity of the Boson peak to that of the van Hove peak shows a kink near the glass transition temperature as determined by differential scanning calorimetry. Careful analysis of the Raman spectra confirms that this is related to a change in the phonon density of states at the transition temperature. This makes low-frequency Raman a promising technique for thermal characterization of polymers because not only is this technique chemically agnostic and contactless but also it requires neither intensity calibration nor deconvolution nor chemometric analysis. [ABSTRACT FROM AUTHOR]

Machine learning (ML) can be a powerful tool to expedite materials research, but the deployment for experimental research is often hindered by data scarcity and model uncertainty. An human‐in‐the‐loop procedure to tailor the implementation of ML for multicriteria optimization is described. The effectiveness of this procedure in the development of a nafion‐based membrane electrode assembly for electrochemical CO2 reduction reaction (CO2RR) into CO for two targets is demonstrated: energy efficiency (EE) and partial current density for CO2RR (jCO2RR). Model‐agnostic nonlinear correlation analyses identify the 11 features relevant to those targets. The three studied decision tree‐based ML models yield similar cross‐validation errors so an ad hoc feature analysis of the models is done with SHapley Additive exPlanations and nonlinear correlation techniques. The predicted EE‐jCO2RR space and the functional dependency of the predictions are investigated to assess model plausibility. A genetic algorithm with CO production cost as the final target with subsequent validation experiments of candidate conditions is devised. The model chosen through ad hoc analysis yields the highest accuracy and the only one that can locate the Pareto front with a single round of experiments, demonstrating how appropriate model selection through careful inspection can greatly accelerate the research cycle. [ABSTRACT FROM AUTHOR]