Berlin 2015 – scientific programme
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KR: Fachgruppe Kristallographie
KR 3: Poster Session on Ferroic Domain Walls - Multiferroics (DF jointly with KR, MA, TT)
KR 3.17: Poster
Monday, March 16, 2015, 19:00–21:00, Poster C
Structural investigation of erythrosiderites by single crystal X-ray diffraction — •Tobias Fröhlich1, Ladisliv Bohatý2, Petra Becker2, and Markus Braden1 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Kristallographie, Universität zu Köln
Erythrosiderites A2[FeX5(H2O)], where A stands for an alkali metal or ammonium ion and X for a halide ion, are antiferromagnets with Néel-temperatures ranging from 6 to 23 K [1]. This family of compounds allows to investigate the impact of structural parameters on the magnetoelectric properties by comparing their closely related structures. The compound (NH4)2[FeCl5(H2O)] was found to be multiferroic with strong magnetoelectric coupling [2]. While most structures of erythrosiderites crystallize in the space group Pnma, Cs2[FeCl5(H2O)] structurally deviates from the other erythrosiderides and crystallizes in space group Cmcm [3]. The structures of (NH4)2[FeCl5(H2O)] and Cs2[FeCl5(H2O)] are investigated by single-crystal X-ray diffraction. Additionally, the non-magnetic compound (NH4)2[InCl5(H2O)] is structurally investigated. Irrespective the absence of magnetism, its crystal structure is very similar to that of (NH4)2[FeCl5(H2O)], therefore it can be used as a reference material to separate magnetoelectric effects.
[1] J. Luzón et al., Physical Review B, 78, 054414 (2008). [2] M. Ackermann, D. Brüning, T. Lorenz, P. Becker, L. Bohatý, New Journal of Physics 15, 123001 (2013). [3] M. Ackermann, T. Lorenz, P. Becker, L. Bohatý, J. Phys.: Condens. Matter 26, 206002 (2014).