The relationship between vacancy ordering and magnetism in TlFe(1.6)Se(2) has been investigated via single crystal neutron diffraction, nuclear forward scattering, and transmission electron microscopy. The examination of chemically and structurally homogeneous crystals allows the true ground state to be revealed, which is characterized by Fe moments lying in the ab plane below 100 K. This is in sharp contrast to crystals containing regions of order and disorder, where a competition between c axis and ab plane orientations of the moments is observed. The properties of partially disordered TlFe(1.6)Se(2) are, therefore, not associated with solely the ordered or disordered regions. This contrasts the viewpoint that phase separation results in independent physical properties in intercalated iron selenides, suggesting a coupling between ordered and disordered regions may play an important role in the superconducting analogues.
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http://dx.doi.org/10.1103/PhysRevLett.109.077003 | DOI Listing |
Molecules
January 2025
Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
Rare earth phosphate (XPO) is an extremely important rare earth compound. It can exhibit excellent activity and stability in catalytic applications by modifying its inherent properties. Porous single-crystalline (PSC) PrPO and SmPO with a large surface area consist of ordered lattices and disordered interconnected pores, resulting in activity similar to nanocrystals and stability resembling bulk crystals.
View Article and Find Full Text PDFInorg Chem
January 2025
CNRS, University of Bordeaux, Bordeaux INP, ICMCB UMR CNRS 5026, F-33600 Pessac ,France.
The diaspore-type crystalline structure is historically well-known in mineralogy, but it has also been widely studied for various applications in the field of catalysis, electrocatalysis, and batteries. However, once two anions of similar ionic size but different electronegativity, such as F and O or more precisely OH, are combined, the knowledge of the location of these two anions is of paramount importance to understand the chemical properties in relation with the generation of hydrogen bonds. Coprecipitation and hydrothermal routes were used to prepare hydroxide-fluorides that crystallize all in an orthorhombic structure with four formula units per cell.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
DICP: Chinese Academy of Sciences Dalian Institute of Chemical Physics, State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, CHINA.
Broad-temperature optical thermometry necessitates materials with exceptional sensitivity and stability across varied thermal conditions, presenting challenges for conventional systems. Here, we report a lead-free, vacancy-ordered perovskite Cs2TeCl6, that achieves precise temperature sensing through a novel combination of self-trapped excitons (STEs) photoluminescence (PL) lifetime modulation and unprecedented fifth-order phonon anharmonicity. The STEs PL lifetime demonstrates a highly temperature-sensitive response from 200 to 300 K, ideal for low-to-intermediate thermal sensing.
View Article and Find Full Text PDFChem Sci
January 2025
Applied Chemistry and Environmental Science, School of Science, STEM College, RMIT University Melbourne Victoria 3000 Australia
High-temperature reduction of TiO causes the gradual formation of structural defects, leading to oxygen vacancy planar defects and giving rise to Magnéli phases, which are substoichiometric titanium oxides that follow the formula Ti O, with 4 ≤ ≤ 9. A high concentration of defects provides several possible configurations for Ti and Ti within the crystal, with the variation in charge ordered states changing the electronic structure of the material. The changes in crystal and electronic structures of Magnéli phases introduce unique properties absent in TiO, facilitating their diverse applications.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
College of Carbon Neutrality Future Technology, Sichuan University, Chengdu, Sichuan 610065, China; National Engineering Research Center for Flue Gas Desulfurization, Chengdu, Sichuan 610065, China; Industrial Technology Research Institute, Sichuan University, Yibin 644004, China. Electronic address:
This study investigates the critical relationship between the crystal phase, morphology, and photocatalytic activity of MnO. The δ-MnO nanosheets, characterized by multiple exposed crystal planes forming junctions, exhibit optimized optical and electrical properties. Oxygen vacancy concentrations were observed in the order δ-MnO > γ-MnO > α-MnO, with corresponding increases in band gap width from 1.
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