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TT: Fachverband Tiefe Temperaturen
TT 42: Correlated Electrons: f-Electron Systems and Heavy Fermions 2
TT 42.8: Vortrag
Mittwoch, 18. März 2020, 17:00–17:15, HSZ 204
Crystallographic structure and magnetism of UNi4B — •Jannis Willwater1, Stefan Süllow1, Milan Klicpera2, Michal Valiska2, Vladimir Sechovsky2, Bachir Ouladdiaf3, and Hiroshi Amitsuka4 — 1IPKM, TU Braunschweig, Germany — 2Department of Condensed Matter Physics, Charles University, Czech Republic — 3Institut Laue-Langevin, France — 4Department of Condensed Matter Physics, Japan
The frustrated intermetallic magnet UNi4B has been reported to crystallize in a hexagonal crystallographic structure and to exhibit a peculiar type of partial magnetic order at low temperatures. Recently, synchrotron x-ray diffraction data have indicated that the structure is orthorhombic and not hexagonal. The best description of the crystal structure at 300 K was obtained with the space group 63 (Cmcm). In this situation, to understand the nature of the magnetic transitions at low temperature, it requires the determination of the low temperature crystallographic symmetry. Therefore, we have studied a 11B enriched single crystal UNi4B, here using elastic neutron scattering. In our experiment, various structural Bragg peaks forbidden for the Cmcm symmetry have been detected and indicate that the symmetry of the crystal structure is even lower. From fits to our data, we have obtained the best description of the structure with the orthorhombic space group 25 (Pmm2). Further we have detected various magnetic Bragg peaks and established their temperature dependence.