The local structure of the highly "overdoped" 95 K superconductor SrCuO determined by Cu K X-ray absorption fine structure (XAFS) at 62 K in magnetically oriented samples shows that 1) the magnetization is perpendicular to the axis; 2) at these levels of precision the Cu sublattice is tetragonal in agreement with the crystal structure; the O sublattice has 3) continuous -Cu-O- chains that orient perpendicular to an applied magnetic field; 4) approximately half-filled -Cu-O- chains that orient parallel to this field; 5) a substantial number of apical O vacancies; 6) O ions at some apical positions with expanded Cu-O distances; and 7) interstitial positions that imply highly displaced Sr ions. These results contradict the universally accepted features of cuprates that require intact CuO planes, magnetization along the axis, and a termination of the superconductivity when the excess charge on the CuO Cu ions exceeds 0.27. These radical differences in charge and structure demonstrate that this compound constitutes a separate class of Cu-O-based superconductors in which the superconductivity originates in a different, more complicated structural unit than CuO planes while retaining exceptionally high transition temperatures.
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http://dx.doi.org/10.1073/pnas.1918890117 | DOI Listing |
J Colloid Interface Sci
December 2024
Key Laboratory of Groundwater Resources and Environment (Jilin University), Ministry of Education, College of New Energy and Environment, Jilin University, Changchun 130021, China. Electronic address:
As the frontier of environmental catalysis, mercury removal by deNO unit over bifunctional catalyst has emerged. However, it is fundamentally challenging to achieve simultaneous NO and mercury removal in industrial flue gas due to the commercial selective catalytic reduction (SCR) molecular sieves' lack of demercuration active centers. Herein, we demonstrate an active site in situ reconfiguration approach to enhance the oxidation of elemental mercury and immobilize divalent mercury by modified commercial SCR catalysts.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Center of New Technologies, University of Warsaw, 02089 Warsaw, Poland.
Based on density functional theory calculations, we propose a new pathway toward compounds featuring flat [AgF] layers which mimic [CuO] layers in high-temperature oxocuprate superconductor precursors. Calculations predict the dynamic (phonon) and energetic stability of the new phases over diverse substrates. For some compounds with ferro orbital ordering, we find a gigantic intrasheet superexchange constant of up to -211 meV (DFT+) and -256 meV (SCAN), calculated for hypothetical (CsMgF)KAgF intergrowth.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, 999077, China.
Curr Microbiol
November 2024
Department of Research and Development, Paktex Industries, 2.5 KM Tatlay Road, Saroya Abad, Kamoke, 52470, Pakistan.
The emergence of resistant bacterial and fungal strains poses significant challenges in various industrial processes including food, medicines, and leather industry. It necessitates the development of novel and effective antimicrobial agents. In the present work, we have developed an ecofriendly and sustainable approach to synthesize silver-doped copper oxide nanoparticles by using cinnamon bark extract (C-CuO/Ag).
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
University of Science, Vietnam National University, Ho Chi Minh City 700000, Viet Nam; Vietnam National University, Ho Chi Minh City 700000, Viet Nam. Electronic address:
The utilization of agricultural by-products for the synthesis of hybrid nanomaterials represents an environmentally sustainable approach. This research aims to comprehensively investigate high-performance silver and copper nanoparticles hybrid materials based on carboxymethyl-modified cellulose / lignin derived from rice husks (CMC / CML-AgNPs and CMC / CML-CuONPs) and apply them for antimicrobial activities. CMC / CML was used to reduce Ag / Cu cations to the atomic level and then efficiently stabilize Ag / CuO nanoparticles, an eco-friendly method and sustainable development.
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