Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 106: Complex Oxides: Bulk Properties, Surfaces and Interfaces (joint session TT/MA/KFM)

TT 106.10: Vortrag

Freitag, 16. März 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 Klingeler^{1, 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 T_N = 17 K.