Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2

article Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2 published yes Valeska Zambra author 467ed36b-dc96-11ea-b7c8-b043a380b2820000-0002-8806-5719 Amit Nathwani author 1a362536-4d02-11f1-8543-8351136efc50 Muhammad Nauman author 32c21954-2022-11eb-9d5f-af9f93c24e710000-0002-2111-4846 Sylvia K. Lewin author Corey E. Frank author Nicholas P. Butch author Arkady Shekhter author B. J. Ramshaw author Kimberly A Modic author 13C26AC0-EB69-11E9-87C6-5F3BE66974250000-0001-9760-3147 KiMo department GradSch department Gaining leverage with spin liquids and superconductors project UTe2 exhibits the remarkable phenomenon of re-entrant superconductivity, whereby the zero-resistance state reappears above 40 tesla after being suppressed with a field of around 10 tesla. One potential pairing mechanism, invoked in the related re-entrant superconductors UCoGe and URhGe, involves transverse fluctuations of a ferromagnetic order parameter. However, the requisite ferromagnetic order—present in both UCoGe and URhGe—is absent in UTe2, and neutron scattering shows instead that the magnetic susceptibility is peaked at an antiferromagnetic wavevector. Here, we measure the magnetotropic susceptibility of UTe2 across two field-angle planes. This quantity is sensitive to the magnetic susceptibility in a direction transverse to the applied magnetic field—a quantity that is not accessed in conventional magnetization measurements. We observe a very large decrease in the magnetotropic susceptibility over a broad range of field orientations, indicating a large increase in the transverse magnetic susceptibility. Because our technique probes the magnetic susceptibility in the long wavelength (q = 0) limit, this suggests that the strong transverse susceptibility arises from ferromagnetic spin fluctuations. These ferromagnetic fluctuations are likely important for understanding the pairing mechanism in UTe2, as all three superconducting phases of UTe2 surround this region of enhanced susceptibility in the field-angle phase diagram. https://research-explorer.ista.ac.at/download/21845/21850/2026_NatureComm_Zambra.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ Springer Nature2026 eng Nature Communications 2041-1723 2506.0898410.1038/s41467-026-71899-7 17 https://research-explorer.ista.ac.at/record/21174 Zambra, Valeska, Amit Nathwani, Muhammad Nauman, Sylvia K. Lewin, Corey E. Frank, Nicholas P. Butch, Arkady Shekhter, B. J. Ramshaw, and Kimberly A Modic. “Giant Transverse Magnetic Fluctuations at the Edge of Re-Entrant Superconductivity in UTe2.” Nature Communications. Springer Nature, 2026. <a href="https://doi.org/10.1038/s41467-026-71899-7">https://doi.org/10.1038/s41467-026-71899-7</a>. Zambra, V., Nathwani, A., Nauman, M., Lewin, S. K., Frank, C. E., Butch, N. P., … Modic, K. A. (2026). Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2. Nature Communications. Springer Nature. <a href="https://doi.org/10.1038/s41467-026-71899-7">https://doi.org/10.1038/s41467-026-71899-7</a> V. Zambra, A. Nathwani, M. Nauman, S.K. Lewin, C.E. Frank, N.P. Butch, A. Shekhter, B.J. Ramshaw, K.A. Modic, Nature Communications 17 (2026). Zambra V, Nathwani A, Nauman M, et al. Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2. Nature Communications. 2026;17. doi:<a href="https://doi.org/10.1038/s41467-026-71899-7">10.1038/s41467-026-71899-7</a> Zambra V, Nathwani A, Nauman M, Lewin SK, Frank CE, Butch NP, Shekhter A, Ramshaw BJ, Modic KA. 2026. Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2. Nature Communications. 17, 3742. Zambra, Valeska, et al. “Giant Transverse Magnetic Fluctuations at the Edge of Re-Entrant Superconductivity in UTe2.” Nature Communications, vol. 17, 3742, Springer Nature, 2026, doi:<a href="https://doi.org/10.1038/s41467-026-71899-7">10.1038/s41467-026-71899-7</a>. V. Zambra et al., “Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe2,” Nature Communications, vol. 17. Springer Nature, 2026. 218452026-05-10T22:02:15Z2026-05-11T06:36:00Z