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)A˚ , b=14.793(9)A˚ , c=17.126(8)A˚). We determine the magnetically ordered structure, concluding that below TN=19.5K 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 330mK, 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.
@article{arxiv.2104.06119,
title = {Crystallographic and magnetic structure of UNi$_4$$^{11}$B},
author = {J. Willwater and S. Süllow and M. Reehuis and R. Feyerherm and H. Amitsuka and B. Ouladdiaf and E. Suard and M. Klicpera and M. Vališka and J. Pospíšil and V. Sechovský},
journal= {arXiv preprint arXiv:2104.06119},
year = {2021}
}