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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 28: Complex Oxides: Bulk Properties, Surfaces and Interfaces (joint session TT/MA/KFM)
KFM 28.10: Talk
Friday, March 16, 2018, 12:00–12:15, H 0110
Growth and characterization of Pmnb-Li2FeSiO4 single crystals — •Waldemar Hergett1, Christoph Neef1, Hubert Wadepohl2, Hans-Peter Meyer3, Mahmoud Abdel-Hafiez4, and Rüdiger Klingeler1, 5 — 1Kirchhoff Institute of Physics, Heidelberg University, Heidelberg, Germany — 2Institute of Inorganic Chemistry, Heidelberg University, Heidelberg, Germany — 3Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany — 4Institute of Physics, Goethe University, Frankfurt, Germany — 5Center for Advanced Materials, Heidelberg University, Heidelberg, Germany.
Li2FeSiO4 single crystals featuring the high temperature Pmnb phase were grown by the high-pressure optical floating zone method. The resulting single crystals have been characterized by means of polarised-light and electron microscopy, EDX, powder and single crystal X-ray diffraction. The impact of the growth parameters and of the applied pressure on the crystal quality was investigated. The single crystal structure of the Pmnb-polymorph was solved for the first time. It exhibits layers of corner-sharing FeO4- and SiO4-tetrahedra in the crystallographic ac-planes which alternate with layers of LiO4-tetrahedra. Magnetisation and specific heat studies confirm the high quality of the crystals and show a sharp λ-like anomaly associated with the onset of long-range antiferromagnetic order at TN = 17 K.