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MM: Fachverband Metall- und Materialphysik
MM 17: Postersession I
MM 17.29: Poster
Monday, March 16, 2015, 18:00–20:00, Poster E
Pressure-induced spin transition of Fe2+ in siderite FeCO3 studied by x-ray Raman scattering — •Christopher Weis1, Christian Sternemann1, Max Wilke2, Valerio Cerantola3, Christoph J. Sahle4, Georg Spiekermann5, and Metin Tolan1 — 1Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany — 2Helmholtz-Zentrum Potsdam, German Research Centre for Geoscience (GFZ), 14473 — 3Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany — 4ESRF, 38043 Grenoble Cedex 9, France — 5Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
Pressure-induced electronic and/or structural transitions of iron bearing compounds at conditions of the inner earth fundamentally affect the material’s properties, e.g. sound velocitiy and density. Siderite (FeCO3) forms a complete solid solution with magnesite (MgCO3). Owing to the low solubility of carbon in the mantle it is a candidate for carbon storage and a key mineral to understand the Earth’s carbon cycle. Lavina et al. [1] applied high-pressure x-ray diffraction to siderite and found a high-spin to low-spin transition to occur at 43-49 GPa with a sharp volume collapse of 10 % at a pressure of 44 to 45 GPa. We investigated changes in the electronic structure of a siderite single crystal for pressures up to 50 GPa using a Boehler-Almax diamond anvil cell with helium as pressure medium by x-ray Raman scattering at the iron M2,3-edge and L2,3-edge. The course of the spin transition up to 50 GPa is discussed by the observed spectral changes. [1] B. Lavina et al., Geophys. Res. Lett. 36, L23306 (2009)