Chalk River Laboratories

About: Chalk River Laboratories is a based out in . It is known for research contribution in the topics: Neutron diffraction & Neutron scattering. The organization has 2297 authors who have published 2700 publications receiving 73287 citations.

Long-Range Antiferromagnetic Ordering in the Novel Magnetically Frustrated Rock Salt Oxide System: Li3Mg2RuO6

Abstract: The new ruthenate, Li3Mg2RuO6, was synthesized in polycrystalline form by a solid-state method. The crystal structure of Li3Mg2RuO6 was refined from powder neutron diffraction data in the orthorhombic Fddd space group in an ordered NaCl structure type with a = 5.8759 (2) A, b = 8.4206 (1) A, and c = 17.6455 (5) A. The Ru5+ (S = 3/2) sublattice shows a unique topology, which consists of chains of edge-sharing triangles interconnected by corner sharing and thus there exists the potential for geometric magnetic frustration. This is the first time that magnetic behavior of a material with such sublattice has been investigated. The isostructural, nonmagnetic Li3Mg2NbO6 was prepared as the lattice match for the heat capacity analysis. The temperature-dependent magnetic susceptibility, heat capacity, and neutron diffraction data reveal that the system undergoes a long-range AFM ordering below 17 K but also provide evidence for short-range spin correlations well above TN. The magnetic frustration index, f ≈ 109/1...

Magnetic phase transition in V2O3 nanocrystals

Abstract: V{sub 2}O{sub 3} nanocrystals can be synthesized through hydrothermal reduction in VO(OH){sub 2} using hydrazine as a reducing agent. Addition of different ligands to the reaction produces nanoparticles, nanorods, and nanoplatelets of different sizes. Small nanoparticles synthesized in this manner show suppression of the magnetic phase transition to lower temperatures. Using muon spin relaxation spectroscopy and synchrotron x-ray diffraction, we have determined that the volume fraction of the high-temperature phase, characterized by a rhombohedral structure and paramagnetism, gradually declines with decreasing temperature, in contrast to the sharp transition observed in bulk V{sub 2}O{sub 3}.

Surface-Enhanced Infrared Spectroscopy and Neutron Reflectivity Studies of Ubiquinone in Hybrid Bilayer Membranes under Potential Control.

Abstract: Surface-enhanced infrared adsorption spectroscopy (SEIRAS) and neutron reflectometry (NR) were employed to characterize ubiquinone (UQ) containing hybrid bilayer membranes. The biomimetic membrane was prepared by fusing phospholipid vesicles on a hydrophobic octadecanethiol monolayer self-assembled on a thin gold film. Using SEIRAS, the assembly of the membrane is monitored in situ. The presence of ubiquinone is verified by the characteristic carbonyl peaks from the quinone ester. A well-ordered distal lipid leaflet results from fusion of vesicles with and without the addition of ubiquinone. With applied potential, the hybrid bilayer membrane in the absence of UQ behaves in the same way as previously reported solid supported phospholipid membranes. When ubiquinone is incorporated in the membrane, electric field induced changes in the distal leaflet are suppressed. Changes in the infrared vibrations of the ubiquinone due to applied potential indicate the head groups are located in both polar and nonpolar environments. The spectroscopic data reveal that the isoprenoid unit of the ubiquinone is likely lying in the midplane of the lipid bilayer while the head has some freedom to move within the hydrophobic core. The SEIRAS experiments show redox behavior of UQ incorporated in a model lipid membrane that are otherwise inaccessible with traditional electrochemistry techniques.