New insights into the magnetism and magnetic structure of LuCrO perovskite.

A polycrystalline sample LuCrO has been characterized by neutron powder diffraction (NPD) and magnetization measurements. Its crystal structure has been Rietveld refined from NPD data in space group Pnma; this perovskite contains strongly tilted CrO octahedra with extremely bent Cr-O-Cr superexchange angles of ∼142°. The NPD data show that below Néel temperature (T ≃ 131 K), the magnetic structure can be defined as an A-type antiferromagnetic arrangement of Cr magnetic moments, aligned along the b axis, with a canting along the c axis.

Guidelines for communicating commensurate magnetic structures. A report of the International Union of Crystallography Commission on Magnetic Structures.

A report from the International Union of Crystallography Commission on Magnetic Structures outlining the recommendations for communicating commensurate magnetic structures.

Unveiling the Structural Properties, Optical Behavior, and Thermoelectric Performance of 2D CsSnBr Halide Obtained by Mechanochemistry.

Metal halide perovskites with a two-dimensional structure are utilized in photovoltaics and optoelectronics. High-crystallinity CsSnBr specimens have been synthesized via ball milling. Differential scanning calorimetry curves show melting at 553 K (endothermic) and recrystallization at 516 K (exothermic).

Exploring Reversible Redox Behavior in the 6H-BaFeO (0 < δ < 0.4) System: Impact of Fe/Fe Ratio on CO Oxidation.

This work is devoted to evaluating the relationship between the oxygen content and catalytic activity in the CO oxidation process of the 6H-type BaFeO system. Strong evidence is provided about the improvement of catalytic performance with increasing Fe average oxidation state, thus suggesting the involvement of lattice oxygen in the catalytic process. The compositional and structural changes taking place in both the anionic and cationic sublattices of the catalysts during redox cycles have been determined by temperature-resolved neutron diffraction.

SrMoO Perovskite with Segregated Ru Nanoparticles Performing as Anode in Solid Oxide Fuel Cells.

A new anode material, Ru-SrMoO, with a perovskite structure and segregated metallic Ru, has been tested in an intermediate-temperature solid oxide fuel cell (IT-SOFC) in an electrolyte-supported configuration giving substantial power densities as high as 840 mW/cm at 850 °C using pure H as fuel. This material has been prepared by the citrate method and structurally and microstructurally characterized at room temperature by different techniques such as X-ray diffraction (XRD), neutron powder diffraction (NPD), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM). NPD was very useful to determine oxygen positions and vacancies, unveiling a cubic and oxygen-deficient perovskite SrMoO oxide with a 3 space group and potential ionic mobility.

Structural Features and Optical Properties of All-Inorganic Zero-Dimensional Halides CsPbBrI Obtained by Mechanochemistry.

Despite the great success of hybrid CHNHPbI perovskite in photovoltaics, ascribed to its excellent optical absorption properties, its instability toward moisture is still an insurmountable drawback. All-inorganic perovskites are much less sensitive to humidity and have potential interest for solar cell applications. Alternative strategies have been developed to design novel materials with appealing properties, which include different topologies for the octahedral arrangements from three-dimensional (3D, e.

Characterization of Tunneled Wide Band Gap Mixed Conductors: The NaO-GaO-TiO System.

This article focuses on the NaO-GaO-TiO system, which is barely explored in the study of transparent conductive oxides (TCOs). NaGaTiO (n = 5, 6, and 7 and x ≈ 0.7-0.

Reduced Thermal Conductivity in Nanostructured AgSbTe Thermoelectric Material, Obtained by Arc-Melting.

AgSbTe intermetallic compound is a promising thermoelectric material. It has also been described as necessary to obtain LAST and TAGS alloys, some of the best performing thermoelectrics of the last decades. Due to the random location of Ag and Sb atoms in the crystal structure, the electronic structure is highly influenced by the atomic ordering of these atoms and makes the accurate determination of the Ag/Sb occupancy of paramount importance.

Crystal structure thermal evolution and novel orthorhombic phase of methylammonium lead bromide, CHNHPbBr.

Methylammonium (MA) lead trihalide perovskites, CHNHPbX (X = I, Br, Cl), have emerged as a new class of light-absorbing materials for photovoltaic applications, reaching efficiencies of 23% when implemented in solar cell heterojunctions. In particular, MAPbBr is a promising member with a large bandgap that gives rise to a high open circuit voltage. Here we present a structural study from neutron diffraction (ND) data of an undeuterated MAPbBr specimen, carried out to follow its crystallographic behaviour in the 2-298 K temperature range.

Atomic distribution and local structure in-situ VII from in situ neutron diffraction.

Ice polymorphs show extraordinary structural diversity depending on pressure and temperature. The behavior of hydrogen-bond disorder not only is a key ingredient for their structural diversity but also controls their physical properties. However, it has been a challenge to determine the details of the disordered structure in ice polymorphs under pressure, because of the limited observable reciprocal space and inaccuracies related to high-pressure techniques.

Al-Doped SrMoO Perovskites as Promising Anode Materials in Solid Oxide Fuel Cells.

Two perovskite materials with SrMoAlO (x = 0.1, 0.2) compositions have been synthesized by reduction from the corresponding scheelite phases, with SrMoAlO stoichiometry; the pertinent characterization shows that the defective perovskites can be used as anode materials in solid oxide fuel cells, providing maximum output power densities of 633 mW/cm for x = 0.

Nitridation effect on lithium iron phosphate cathode for rechargeable batteries.

A novel oxynitride LiFePON with olivine structure (space group , no. 62) has been synthesized by heating a parent LiFePO precursor obtained by citrate chemistry in flowing ammonia at 650 °C. The polycrystalline sample has been characterized by X-ray and neutron powder diffraction (NPD), elemental and thermal analysis, scanning electron microscopy (SEM) and electrochemical measurements.

Detailed Structural Features of the Perovskite-Related Halide RbPbI for Solar Cell Applications.

All-inorganic lead halide perovskites like CsPbBr, CsPbI, or RbPbI are good replacements for the classical hybrid organic-inorganic perovskites like CHNHPbI, susceptible to fast degradation in the presence of humid air. They also exhibit outstanding light absorption properties suitable for solar energy applications. Here, we describe the synthesis of RbPbI by mechanochemical procedures with green credentials, avoiding toxic or expensive organic solvents; this specimen exhibits excellent crystallinity.

On the magnetic structure and magnetic behaviour of the most distorted member of the series of RNiO perovskites (R = Lu).

The crystal structure of LuNiO perovskite has been examined below RT and across = 125 K by neutron powder diffraction. In this temperature region (2-298 K), well below the metal-insulator transition this oxide exhibits at = 599 K, this material is insulating and characterized by a partial charge disproportionation of the Ni valence. In the perovskite structure, defined in the monoclinic 2/ space group, there are two inequivalent Ni sites located in alternating octahedra of different sizes.

Exceptional Low-Temperature CO Oxidation over Noble-Metal-Free Iron-Doped Hollandites: An In-Depth Analysis of the Influence of the Defect Structure on Catalytic Performance.

A family of iron-doped manganese-related hollandites, K Mn Fe O (0 ≤ ≤ 0.15), with high performance in CO oxidation have been prepared. Among them, the most active catalyst, KMnFeO(OH), is able to oxidize more than 50% of CO at room temperature.

Influence of Polymorphism on the Magnetic Properties of CoTeO Spinel.

This study presents the influence of polymorphism on the magnetic properties of CoTeO. This compound with a spinel-like structure [Co][CoTe]O was synthesized into two polymorphs: one disordered within a cubic 3̅ structure, where Co and Te ions are randomly distributed on the octahedral B sites [the disordered polymorph can also be presented as an inverse spinel of the formula Co(CoTe)O] and the other ordered with a cubic 432 structure where Co and Te ions are ordered on the B sites. The macroscopic magnetic measurements showed that both polymorphs present a ferrimagnetic ordering, below ∼40 K, and a second transition is also observed at 27 K for the ordered polymorph.

Synergy of diffraction and spectroscopic techniques to unveil the crystal structure of antimonic acid.

The elusive crystal structure of the so-called 'antimonic acid' has been investigated by means of robust and state-of-the-art techniques. The synergic results of solid-state magic-angle spinning nuclear magnetic resonance spectroscopy and a combined Rietveld refinement from synchrotron X-ray and neutron powder diffraction data reveal that this compound contains two types of protons, in a pyrochlore-type structure of stoichiometric formula (HO)HSbO. Some protons belong to heavily delocalized HO subunits, while some H are directly bonded to the oxygen atoms of the covalent framework of the pyrochlore structure, with O-H distances close to 1 Å.

A Monolithic Solid-State Sodium-Sulfur Battery with Al-Doped NaZr(SiPO) Electrolyte.

The limit of the energy density and increasing security issues on sodium-ion batteries (SIBs) impede their further development. Solid-state sodium metal batteries are potential candidates to replace the present SIBs. However, low ionic conductivity and poor interface contact hinder their progress.

Identifying the presence of magnetite in an ensemble of iron-oxide nanoparticles: a comparative neutron diffraction study between bulk and nanoscale.

Scientific interest in iron-oxides and in particular magnetite has been renewed due to the broad scope of their fascinating properties, which are finding applications in electronics and biomedicine. Specifically, iron oxide nanoparticles (IONPs) are gathering attraction in biomedicine. Their cores are usually constituted by a mixture of maghemite and magnetite phases.

A comprehensive examination of the local- and long-range structure of SbO pyrochlore oxide.

The crystal structure of the SbO oxide, exhibiting a defect pyrochlore crystal structure with atomic vacancies, has been studied using a complete set of state-of-the-art techniques. The degree of antimony disproportionation in Sb and Sb valence states has been directly determined around 36% and 64%, respectively, using X-ray absorption near edge structure (XANES). These findings are in excellent agreement with our Rietveld analysis of synchrotron X-ray (SXRD) and neutron powder diffraction (NPD) results.

Topotactic Oxidation of Perovskites to Novel SrMoMO (M = Fe and Cr) Deficient Scheelite-Type Oxides.

New polycrystalline SrMoMO (M = Fe and Cr) scheelite oxides have been prepared by topotactical oxidation, by annealing in air at 500 °C, from precursor perovskites with the stoichiometry SrMoMO (M = Fe and Cr). An excellent reversibility between the oxidized Sr(Mo,M)O scheelite and the reduced Sr(Mo,M)O perovskite phase accounts for the excellent behavior of the latter as anode material in solid-oxide fuel cells. A characterization by X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) has been carried out to determine the crystal structure features.

Structural Features, Anisotropic Thermal Expansion, and Thermoelectric Performance in Bulk Black Phosphorus Synthesized under High Pressure.

Black phosphorus (BP) allotrope has an orthorhombic crystal structure with a narrow bandgap of 0.35 eV. This material is promising for 2D technology since it can be exfoliated down to one single layer: the well-known phosphorene.

Structure-properties relationship in the hydronium-containing pyrochlores (HO)SbTeO with catalytic activity in the fructose dehydration reaction.

A series of defect pyrochlores of the composition (H3O)1+pSb1+pTe1-pO6 have been prepared by ion exchange from K-containing pyrochlores K1+pSb1+pTe1-pO6 in sulfuric acid at 280 °C for 24 h. The structural characterization of the hydronium-containing pyrochlores, including the location of the H3O+ units within the three-dimensional framework, was possible from neutron powder diffraction data in undeuterated samples. The crystal structure for all the compounds is defined in the Fd3[combining macron]m space group, and consists of a covalent framework of SbVO6 and TeVIO6 octahedra distributed at random and connected by their vertices with (Sb,Te)-O1-(Sb,Te) angles close to 136°, conforming to large cages where the hydronium species are located off-center.