Dresden 2017 – wissenschaftliches Programm
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KR: Fachgruppe Kristallographie
KR 3: Crystallography - poster session
KR 3.1: Poster
Mittwoch, 22. März 2017, 18:00–20:00, P4
Structural and magneto-electric investigations of Erythrosiderites — •Tobias Fröhlich1, Daniel Brüning1, Ladislav Bohatý2, Petra Becker2, and Markus Braden1 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Kristallographie, Universität zu Köln
Most erythrosiderites of the form A2[FeX5(H2O)] are magneto-electric without multiferroicity. However, in 2013 it was found that the compound (NH4)2[FeCl5(H2O)] is multiferroic. A comparison of macroscopic and microscopic properties of different compounds of this family reveals interesting insights into the structural order and magnetic coupling. While the crystal structures of most erythrosiderites can be described with space group P n m a , Cs2[FeCl5(H2O)] has space group C m c m . In contrast to the other compounds [1, 2], its magnetic structure is not yet directly determined. However, there are investigations of macroscopic quantities, which allow to predict the magnetic structure [3]. We present a neutron study of the magnetic structure of Cs2[FeCl5(H2O)] , which perfectly explains these measurements. Furthermore, Cs2[FeCl5(H2O)] exhibits a structural phase transition which was discovered in 1987 [4]. By single crystal X-ray diffraction, we solved the structural distortion associated with this transition, which involves a slight monoclinic distortion into space group C2/c .
[1] M. Gabás et al. (1995), J. Phys. Condens. Matter 7 4725-4738 [2] J. Rodrígues-Velamazán, et al. (2015), arXiv [3] M. Ackermann et al. (2014), J. Phys. Condens. Matter 26 506002 [4] J. Chadwick et al. (1987), J. Phys. C: Solid State Phys. 20 3979-3983