Field-reentrant superconductivity close to a metamagnetic transition in the heavy-fermion superconductor UTe\(_2\)

• Published in: arXiv.org 2019-05
• Main Authors: Knebel, Georg, Knafo, William, Pourret, Alexandre, Niu, Qun, Vališka, Michal, Braithwaite, Daniel, Lapertot, Gérard, Nardone, Marc, Zitouni, Abdelaziz, Mishra, Sanu, Sheikin, Ilya, Seyfahrt, Gabriel, Jean-Pascal Brison, Aoki, Dai, Flouquet, Jacques
• Format: Article
• Language: English
• Subjects: Critical field (superconductivity); Dependence; Fermions; Heavy fermion superconductors; Magnetic fields; Magnetic variations; Magnetoresistivity; Superconductivity
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1905.05181

We present a study of the upper critical field of the newly discovered heavy fermion superconductor UTe\(_2\) by magnetoresistivity measurements in pulsed magnetic fields up to 60~T and static magnetic fields up to 35~T. We show that superconductivity survives up to the metamagnetic transition at \(H_{\rm m} \approx 35\)~T at low temperature. Above \(H_{\rm m}\) superconductivity is suppressed. At higher temperature superconductivity is enhanced under magnetic field leading to reentrance of superconductivity or an almost temperature independent increase of \(H_{\rm c2}\). By studying the angular dependence of the upper critical field close to the \(b\) axis (hard magnetization axis) we show that the maximum of the reentrant superconductivity temperature is depinned from the metamagnetic field. A key ingredient for the field-reinforcement of superconductivity on approaching \(H_{\rm m}\) appears to be an immediate interplay with magnetic fluctuations and a possible Fermi-surface reconstruction.