High pressure study of UTe2 in pulsed magnetic field

The unconventional superconductivity in the heavy-fermion paramagnet UTe2 has recently attracted a lot of attention, particularly due to the reinforcement of superconductivity with magnetic field, and the probable spin-triplet and possibly topological nature of the superconducting order parameter[1-4]. Pressure is a powerful tuning parameter in this system inducing multiple superconducting phases, changes of the magnetic anisotropy, and long range magnetic order[5-11]. A challenge is now to characterize the effects of combined pressure and magnetic fields applied along variable directions in this strongly anisotropic paramagnet. Several studies under pressure in high static magnetic field have been published, but a full investigation of this system requires magnetic field higher than the maximum available static magnetic fields[7,12,13]. Here, we present an investigation of the electrical resistivity of UTe2 under pressure up to 3 GPa and pulsed magnetic fields up to 58T applied along the hard magnetic directions b and c. We show that, near the critical pressure, a field-enhancement of superconductivity coincides with a boost of the effective mass related to the collapse of metamagnetic and critical fields. These new elements improve our understanding of the interplay between magnetism and superconductivity, and the complex p-T-H phase diagram of this system.

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