Inelastic-neutron-scattering measurements were performed on a single crystal of the heavy-fermion paramagnet UTe2 above its superconducting temperature. We confirm the presence of antiferromagnetic fluctuations with the incommensurate wavevector k1=(0,0.57,0). A quasielastic signal is found, whose momentum-transfer dependence is compatible with fluctuations of magnetic moments μ∥a, with a sine-wave modulation of wavevector k1 and in-phase moments on the nearest U atoms. Low dimensionality of the magnetic fluctuations, consequence of the ladder structure, is indicated by weak correlations along the direction c. These fluctuations saturate below the temperature T1∗≃15~K, in possible relation with anomalies observed in thermodynamic, electrical-transport and nuclear-magnetic-resonance measurements. The absence or weakness of ferromagnetic fluctuations, in our data collected at temperatures down to 2.1 K and energy transfers from 0.6 to 7.5 meV, is emphasized. These results constitute constraints for models of magnetically-mediated superconductivity in UTe2.
@article{arxiv.2106.13087,
title = {Low-dimensional antiferromagnetic fluctuations in the heavy-fermion paramagnetic ladder UTe$_2$},
author = {W. Knafo and G. Knebel and P. Steffens and K. Kaneko and A. Rosuel and J. -P. Brison and J. Flouquet and D. Aoki and G. Lapertot and S. Raymond},
journal= {arXiv preprint arXiv:2106.13087},
year = {2021}
}