Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 4: f-Electron Systems

TT 4.12: Vortrag

Montag, 18. März 2024, 12:45–13:00, H 3005

Magnetic behaviour of UNi₄B in high magnetic fields — •Philip Schröder¹, Jannis Willwater¹, Stefan Süllow¹, Manfred Reehuis², Hiroshi Amitsuka³, Bachir Ouladdiaf⁴, Romain Sibille⁵, Milan Klicpera⁶, Michael Vališka⁶, Jiří Pospíšil⁶, and Vladimír Sechovský⁶ — ¹Institut für Physik der Kondensierten Materie, TU Braunschweig, Germany — ²Helmholtz-Center Berlin for Materials and Energy, Berlin, Germany — ³Department of Physics, Hokkaido University, Japan — ⁴Institute Laue-Langevin, Grenoble, France — ⁵Paul Scherrer Institut, Villingen, Switzerland — ⁶Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic

UNi₄B is a rare example of an ising-like f-electron magnet with a highly unusual form of partial antiferromagnetic ordering at T_N = 19.5 K. Only two thirds of the U-ions participate in long-range magnetic order and form a vortex-like magnetic structure in the pseudo-hexagonal plane. Measurements of the elastic constants verified a complex and highly anisotropic phase diagram, including a plethora of magnetic high field phases. Here we present a comprehensive study of the evolution of the ordered state of UNi₄B in its high field spin-reorienting phases III and III‘ on a microscopic level. We discuss the results of multiple elastic neutron scattering experiments on single crystalline UNi₄B in magnetic fields up to 10 T for H||b and in magnetic fields up to 12 T for H||c. This behaviour might indicate a spin-reorientation and a previously proposed quadrupolar contribution of the non ordering third of U-ions.