Search

Quantum fluctuations inherent in electronic systems positioned close to magnetic instabilities can lead to novel collective phenomena. One such material, β -Ti 6 Sn 5 , sits close to ferromagnetic (FM) instability and can be pushed to an itinerant FM-ordered state with only minute magnetic or non-magnetic doping. The binary nature of this compound, however, limits the tuning variables that can be applied to study any emergent physics, which are likely to be sensitive to the introduction of chemical disorder.Accordingly, we grew high-quality single crystals of a new quaternary compound Zr 3 V 3 GeSn 4 from a Sn-rich self flux, and determined the structure with single-crystal X-ray diffraction. Zr 3 V 3 GeSn 4 forms in an ordered derivative of the hexagonal β -Ti 6 Sn 5 structure with Zr and V atomic positions that show no indication of site interchange. Ge likewise occupies a single unique atomic position. The V site, which would be the one most likely to give rise to any magnetic character, is located at the center of a distorted octahedron of Sn, with such octahedra arranged in face-sharing chains along the crystallographic c axis, while the chains themselves are organized in a kagome geometry. Zr 3 V 3 GeSn 4 represents the second known quaternary phase within this system, suggesting that other compounds with this structure type await discovery. [ABSTRACT FROM AUTHOR]

Single crystals of a new multinary chromium carbide, La21Cr8-2aAlbGe7-bC12 (henicosa­lanthanum octa­chromium aluminium hexa­germanium dodeca­carbide), were grown from an La-rich self flux and were characterized by single-crystal X-ray diffraction. The face-centered cubic crystal structure is composed of isolated and geometrically frustrated regular Cr tetra­hedra that are co-centered within regular C octa­hedra. These mutually separated Cr4-aC6 clusters are distributed throughout a three-dimensional framework of Al, Ge, and La. The title compound is isotypic with La21-Mn8X7C12 and R21Fe8X7C12 (R = La, Ce, Pr; X = Al, Bi, Ge, Sn, Sb, Te) and represents the first example of a Cr-based compound with this structure-type. [ABSTRACT FROM AUTHOR]

Improved methods for the flux growth of single crystals of the important battery material LiFePO4 have been developed, allowing the facile preparation of single crystals up to 1 cm across with well-developed facets at relatively low temperatures. The structural characterization of these samples by both powder X-ray diffraction and single crystal diffraction (X-ray and neutron) indicates that the samples are typically stoichiometric with a very low concentration of Fe defects on the Li site, though crystals with larger concentrations of defects can be specifically grown using Fe-rich fluxes. These defects occur through the formation of a Fe-rich (Li1-2xFex)FePO4 partial solid solution, in contrast to the antisite defects more commonly discussed in the literature which would preserve the ideal LiFePO4 stoichiometry. The LiFePO4 defects are shown to be sarcopside-like (2 Li+ ? Fe2+ + vacancy) based on compositions refined from single crystal diffraction data, the observed dependence of unit cell parameters on defect concentration, and their observed phase behavior (defects only appear in growths from fluxes which are Fe-rich relative to stoichiometric LiFePO4). The distribution of defects has been studied by aberration corrected scanning transmission electron microscopy and was found to be highly inhomogenous, suggesting that defect-containing crystals may consist of endotaxial intergrowths of olivine LiFePO4 and sarcopside Fe3(PO4)2 in a manner that minimizes the detrimental influence of FeLi defects on the rate of Li-ion transport within crystallites. [ABSTRACT FROM AUTHOR]

Large single crystals of LiFePO4 (up to 1 cm diagonal) are obtained besides Li3PO4 and Fe2ClPO4 by the flux growth method using Li3PO4, LiCl, FeCl2, and LiFePO4 as starting materials (graphite crucible, 810 °C, 2 h). [ABSTRACT FROM AUTHOR]