Spin Dynamics and Unconventional Coulomb Phase in Nd2Zr2O7

M. Léger (1) , Elsa Lhotel (1) , M. Ciomaga Hatnean (2) , J. Ollivier (3) , A. r. R Wildes (3) , S. Raymond (4) , E. Ressouche (4) , G. Balakrishnan (2) , S. Petit (5, 6)

1 NEEL - MagSup - Magnétisme et Supraconductivité
2 University of Warwick [Coventry]
3 ILL - Institut Laue-Langevin
4 MEM - Modélisation et Exploration des Matériaux
5 LLB - UMR 12 - Laboratoire Léon Brillouin
6 NFMQ - LLB - Nouvelles frontières dans les matériaux quantiques

We investigate the temperature dependence of the spin dynamics in the pyrochlore magnet Nd2Zr2O7 by neutron scattering experiments. At low temperature, this material undergoes a transition towards an "all in-all out" antiferromagnetic phase and the spin dynamics encompass a dispersion-less mode, characterized by a dynamical spin ice structure factor. Unexpectedly, this mode is found to survive above TN ≈ 300 mK. Concomitantly, elastic correlations of the spin ice type develop. These are the signatures of a peculiar correlated paramagnetic phase which can be considered as a new example of Coulomb phase. Our observations near TN do not reproduce the signatures expected for a Higgs transition, but show reminiscent features of the "all in-all out" order superimposed on a Coulomb phase.

Mots clés: Condensed Matter; Electronic Properties

Domaines: Science des matériaux [cond-mat.mtrl-sci]

M. Léger, Elsa Lhotel, M. Ciomaga Hatnean, J. Ollivier, A. r. R Wildes, et al.. Spin Dynamics and Unconventional Coulomb Phase in Nd2Zr2O7. Physical Review Letters, 2021, 126 (24), pp.247201. ⟨10.1103/PhysRevLett.126.247201⟩. ⟨hal-03285011v2⟩