Field-induced spin-density wave beyond hidden order in URu2Si2

William Knafo (1) , F. Duc (1) , Frederic Bourdarot (2) , K. Kuwahara (3) , H. Nojiri (4) , D. Aoki (4, 5) , Julien Billette (1) , P. Frings (1) , X. Tonon (6) , E. Lelièvre-Berna (6) , J. Flouquet (5) , P. Regnault (6)

1 LNCMI-T - Laboratoire national des champs magnétiques intenses - Toulouse
2 MDN - Magnétisme et Diffusion Neutronique
3 Ibaraki University
4 Tohoku University [Sendai]
5 IMAPEC - Instrumentation, Material and Correlated Electrons Physics
6 ILL - Institut Laue-Langevin

URu2Si2 is one of the most enigmatic strongly correlated electron systems and offers a fertile testing ground for new concepts in condensed matter science. In spite of 430 years of intense research, no consensus on the order parameter of its low-temperature hidden-order phase exists. A strong magnetic field transforms the hidden order into magnetically ordered phases, whose order parameter has also been defying experimental observation. Here, thanks to neutron diffraction under pulsed magnetic fields up to 40 T, we identify the field-induced phases of URu2Si2 as a spin-density-wave state. The transition to the spin-density wave represents a unique touchstone for understanding the hidden-order phase. An intimate relationship between this magnetic structure, the magnetic fluctuations and the Fermi surface is emphasized, calling for dedicated band-structure calculations.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Electrons fortement corrélés [cond-mat.str-el]; Supraconductivité [cond-mat.supr-con]

William Knafo, F. Duc, Frederic Bourdarot, K. Kuwahara, H. Nojiri, et al.. Field-induced spin-density wave beyond hidden order in URu2Si2. Nature Communications, 2016, 7 (1), pp.13075. ⟨10.1038/ncomms13075⟩. ⟨hal-01943387⟩