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  Willwater, J.; Süllow, S.; Reehuis, M.; Feyerherm, R.; Amitsuka, H.; Ouladdiaf, B.; Suard, E.; Klicpera, M.; Valiska, M.; Pospísil, J.; Sechovský, V.: Crystallographic and magnetic structure of UNi₄ ¹¹B. Physical Review B 103 (2021), p. 184426/1-8

10.1103/physrevb.103.184426
Open Access Version (externer Anbieter)

Abstract:
We present an extensive powder and single-crystal neutron scattering investigation of the crystallographic structure and magnetic order of the frustrated metallic f-electron magnet UNi4B. We carry out a full refinement of the crystallographic structure and conclude that the low temperature lattice symmetry is orthorhombic [space group Pmm2; cell parameters: a = 6.963(4), b = 14.793(9), c = 17.126(8) Å]. We determine the magnetically ordered structure, concluding that below TN = 19.5 K, the material undergoes a transition into a partially ordered antiferromagnetic state. The magnetic structure is consistent with the existence of toroidal order in this material. We further test the proposal of a second magnetic transition occurring at 330 mK, concluding that the thermodynamic anomalies observed at these temperatures do not reflect modifications of the magnetic structure. Our study provides a consistent picture of the interrelationship of structural and magnetic properties in the frustrated magnet UNi4B previously unresolved.