Anionic and Magnetic Ordering in Rare Earth Tantalum Oxynitrides with an = 1 Ruddlesden-Popper Structure.

The new compounds RTaON with R = La, Ce, Nd, and Eu and 1.20 ≤ ≤ 2.81 have been obtained by a solid-state reaction between metal nitrides and oxides or oxynitrides under N gas at temperatures between 1200 and 1700 °C.

Prussian Blue Analogues as Positive Electrodes for Mg Batteries: Insights into Mg Intercalation.

Potassium manganese hexacianoferrate has been prepared by co-precipitation from manganese (II) chloride and potassium citrate, with chemical analysis yielding the formula K Mn[Fe(CN) ] □  ⋅ 1.1H O (KMnHCF). Its X-ray diffraction pattern is consistent with a monoclinic structure (space group P 2 /n, no.

High-Temperature Synthesis of Ferromagnetic EuTa(O,N) with a Triple Perovskite Structure.

Europium tantalum perovskite oxynitrides were prepared by a new high-temperature solid-state synthesis under N or N/H gas. The nitrogen stoichiometry was tuned from 0.63 to 1.

Spin-to-Charge Conversion in All-Oxide LaSrMnO/SrIrO Heterostructures.

Spin injection and spin-charge conversion processes in all-oxide LaSrMnO/SrIrO (LSMO/SIO) heterostructures with different SIO layer thickness and interfacial features have been studied. Ferromagnetic resonance (FMR) technique has been used to generate pure spin currents by spin pumping (SP) in ferromagnetic (FM) half-metallic LSMO. The change of the resonance linewidth in bare LSMO layers and LSMO/SIO heterostructures suggests a successful spin injection into the SIO layers.

Synchrotron radiation based characterization of battery materials.

Synchrotron radiation based techniques are powerful tools for battery research and allow probing a wide range of length scales, with different depth sensitivities and spatial/temporal resolutions. experiments enable characterization during functioning of the cell and are thus a precious tool to elucidate the reaction mechanisms taking place. In this perspective, the current state of the art for the most relevant techniques (scattering, spectroscopy, and imaging) is discussed together with the bottlenecks to address, either specific for application in the battery field or more generic.

Artificial Graphene Spin Polarized Electrode for Magnetic Tunnel Junctions.

2D materials offer the ability to expose their electronic structure to manipulations by a proximity effect. This could be harnessed to craft properties of 2D interfaces and van der Waals heterostructures in devices and quantum materials. We explore the possibility to create an artificial spin polarized electrode from graphene through proximity interaction with a ferromagnetic insulator to be used in a magnetic tunnel junction (MTJ).

X-ray Absorption Spectroscopy Study of Thickness Effects on the Structural and Magnetic Properties of PrNiMnO Double Perovskite Thin Films.

In this work, we report a systematic study of the influence of film thickness on the structural and magnetic properties of epitaxial thin films of PrNiMnO (PNMO) double perovskite grown on top of two different (001)-SrTiO and (001)-LaAlO substrates by RF magnetron sputtering. A strong dependence of the structural and magnetic properties on the film thickness is found. The ferromagnetic transition temperature () and saturation magnetization (s) are found to decrease when reducing the film thickness.

β-VO as Magnesium Intercalation Cathode.

Magnesium batteries have attracted great attention as an alternative to Li-ion batteries but still suffer from limited choice of positive electrode materials. VO exhibits high theoretical capacities, but previous studies have been mostly limited to α-VO. Herein, we report on the β-VO polymorph as a Mg intercalation electrode.

Optimization of the Growth Process of Double Perovskite PrNiMnO Epitaxial Thin Films by RF Sputtering.

Epitaxial thin films of PrNiMnO (PNMO) double perovskite were grown on (001)-oriented SrTiO substrates by RF magnetron sputtering. The influence of the growth parameters (oxygen pressure, substrate temperature, and annealing treatments) on the structural, magnetic and transport properties, and stoichiometry of the films was thoroughly investigated. It is found that high-quality epitaxial, insulating, and ferromagnetic PNMO thin films can only be obtained in a narrow deposition parameter window.

Suppression of spin rectification effects in spin pumping experiments.

Spin pumping (SP) is a well-established method to generate pure spin currents allowing efficient spin injection into metals and semiconductors avoiding the problem of impedance mismatch. However, to disentangle pure spin currents from parasitic effects due to spin rectification effects (SRE) is a difficult task that is seriously hampering further developments. Here we propose a simple method that allows suppressing SRE contribution to inverse spin Hall effect (ISHE) voltage signal avoiding long and tedious angle-dependent measurements.

High-Temperature Synthesis and Dielectric Properties of LaTaON.

The development of new synthetic methodologies of perovskite oxynitrides is challenging but necessary for the search of new compounds and the investigation of new properties. Here, we report a new method of preparation of the perovskite LaTaON that has been investigated as a pigment and photocatalyst for water splitting. The synthesis proceeds through the solid-state reactions under N at 1500 °C between LaO, LaN, and TaN or between LaN and TaON, which are completed after 3 h and lead to sintered, highly crystalline samples with particle sizes up to 1 μm.

Synchrotron X-ray Diffraction in Calcium Batteries: Insights into the Redox Activity of 1D CaCoMO (M = Co and Mn).

1D CaCo M O (M = Co = 0, M = Mn = 1, and M = Fe = 0.4) were prepared and tested electrochemically. While the iron-containing phase was not found to be active, the iron- and manganese-containing phases were found to be potentially interesting as positive electrode materials for calcium metal-based high-energy battery technologies and were investigated by synchrotron X-ray diffraction.

Formation of Nickel Oxide Nanocuboids in Ferromagnetic LaNiMnO.

The control of the spontaneous formation of nanostructures at the surface of thin films is of strong interest in many different fields, from catalysts to microelectronics, because surface and interfacial properties may be substantially enhanced. Here, we analyze the formation of nickel oxide nanocuboids on top of LaNiMnO double perovskite ferromagnetic thin films, epitaxially grown on SrTiO (001) substrates by radio-frequency (RF) magnetron sputtering. We show that, by annealing the films at high temperature under high oxygen partial pressure, the spontaneous segregation of nanocuboids is enhanced.

Rapid Thermal Annealing of Double Perovskite Thin Films Formed by Polymer Assisted Deposition.

The annealing process is an important step common to epitaxial films prepared by chemical solution deposition methods. It is so because the final microstructure of the films can be severely affected by the precise features of the thermal processing. In this work we analyze the structural and magnetic properties of double perovskite LaCoMnO and LaNiMnO epitaxial thin films prepared by polymer-assisted deposition (PAD) and crystallized by rapid thermal annealing (RTA).

Engineering Polar Oxynitrides: Hexagonal Perovskite BaWON.

Non-centrosymmetric polar compounds have important technological properties. Reported perovskite oxynitrides show centrosymmetric structures, and for some of them high permittivities have been observed and ascribed to local dipoles induced by partial order of nitride and oxide. Reported here is the first hexagonal perovskite oxynitride BaWON , which shows a polar 6H polytype.

Aqueous Chemical Solution Deposition of Functional Double Perovskite Epitaxial Thin Films.

Double perovskite structure (A BB'O ) oxides exhibit a breadth of multifunctional properties with a huge potential range of applications in fields as diverse as spintronics, magneto-optic devices, or catalysis, and most of these applications require the use of thin films and heterostructures. Chemical solution deposition techniques are appearing as a very promising methodology to achieve epitaxial oxide thin films combining high performance with high throughput and low cost. In addition, the physical properties of these materials are strongly dependent on the ordered arrangement of cations in the double perovskite structure.

Appraisal of calcium ferrites as cathodes for calcium rechargeable batteries: DFT, synthesis, characterization and electrochemistry of CaFeO.

Sustainability combined with high energy density prospects makes Fe-based oxides attractive as cathodes for calcium rechargeable batteries. This work presents a DFT evaluation of the CaFe2+nO4+n (0 < n < 3) family, for which both the average intercalation voltage and the theoretical specific capacity decrease with the increasing n value. The term n = 1/4, Ca4Fe9O17, meets the most appealing characteristics: a calculated average voltage of 4.

On the Study of Ca and Mg Deintercalation from Ternary Tantalum Nitrides.

Layered CaTaN and MgTaN and cubic MgTaN were prepared by direct solid state reaction from the binary nitrides TaN and AN (A: Mg, Ca). CaTaN showed a slight Ca deficiency (0.11 moles per formula), and a monoclinic distortion from previously reported 3̅ symmetry, with space group 2/ and cell parameters = 5.

Crystal Growth Mechanisms of BiFeO Nanoparticles.

A wet-chemical synthesis process was designed to obtain reproducible single-phase multiferroic BiFeO nanoparticles. The phase purity, single crystallinity, and size of the nanoparticles are confirmed through the analysis of X-ray diffraction patterns, Raman spectroscopy, and high resolution transmission electron microscopy experiments. Crystal nucleation happens within the amorphous-rich area in multiple seeds, leading to the formation of single crystalline nanoparticles with no preferential faceting.

Topochemical nitridation of SrFeMoO.

The topotactic nitridation of cation ordered, tetragonal Sr2FeMoO6 in NH3 at moderate temperatures leads to cubic, Fm3[combining macron]m double perovskite oxynitride Sr2FeMoO4.9N1.1 where double-exchange interactions determine ferromagnetic order with TC ≈ 100 K.

Vitamin D measurement and effect on outcome in a cohort of patients with heart failure.

Objectives: The aims of this paper were to evaluate the levels of Vitamin D (VitD) in patients with heart failure (HF), compared to a control group, to assess the effects of VitD on HF outcome and to compare VitD measurement between LIAISON immunoassay and HPLC-MS-MS methods in this population.

Design And Methods: We collected clinical, biochemical and outcome data from 247 patients with HF and in a subgroup of 151 patients, we measured VitD both with LIAISON and HPLC-MS-MS.

Results: HF patients had statistically lower 25OHD levels (45.

Electrochemical calcium extraction from 1D-CaCoO.

The electrochemical oxidation of a transition metal oxide through calcium extraction is achieved for the first time. The 1D framework of Ca3Co2O6 is maintained upon oxidation and the new phase formed exhibits a modulated structure. The process occurs at high potential and is partially reversible, which opens prospects for a calcium battery proof-of-concept.

Confinement generates single-crystal aragonite rods at room temperature.

The topic of calcite and aragonite polymorphism attracts enormous interest from fields including biomineralization and paleogeochemistry. While aragonite is only slightly less thermodynamically stable than calcite under ambient conditions, it typically only forms as a minor product in additive-free solutions at room temperature. However, aragonite is an abundant biomineral, and certain organisms can selectively generate calcite and aragonite.

New rare earth hafnium oxynitride perovskites with photocatalytic activity in water oxidation and reduction.

RHfON perovskites with R = La, Nd and Sm show a GdFeO-type structure and are semiconductors with band gaps of 3.35, 3.40 and 2.

Anisotropic sensor and memory device with a ferromagnetic tunnel barrier as the only magnetic element.

Multiple spin functionalities are probed on Pt/LaCoMnO/Nb:SrTiO, a device composed by a ferromagnetic insulating barrier sandwiched between non-magnetic electrodes. Uniquely, LaCoMnO thin films present strong perpendicular magnetic anisotropy of magnetocrystalline origin, property of major interest for spintronics. The junction has an estimated spin-filtering efficiency of 99.