Possible metamagnetism in the high-pressure tetragonal phase of ${\mathrm{UTe}}_2$

A structural orthorhombic-to-tetragonal phase transition was recently discovered in the heavy-fermion compound ${\mathrm{UTe}}_2$ at a pressure $p^{*}\simeq 3-8\mathrm{GPa}$ [Honda et al., J. Phys. Soc. Jpn. 92, 044702 (2023); Huston et al., Phys. Rev. Mater. 6, 114801 (2022)]. In the high-pressure tetragonal phase, a phase transition at $T_x=235K$ and a superconducting transition at $T_{\text{sc}}=2K$ have been revealed. In this work we present an electrical-resistivity study of ${\mathrm{UTe}}_2$ in pulsed magnetic fields up to ${\mu }_{0}H=58T$ combined with pressures up to $p=6\mathrm{GPa}$. The field was applied in a direction tilted by ${30}^{\circ }$ from b to c in the orthogonal structure, which is identified as the direction c' of the tetragonal structure. In the tetragonal phase, the presence of superconductivity is confirmed and signatures of metamagnetic transitions are observed at the fields ${\mu }_0{H}_{x1}=24T$ and ${\mu }_0{H}_{x2}=34T$ and temperatures smaller than $T_x$. We discuss the effects of uniaxial pressure, and we propose that a magnetic ordering drives the transition at $T_x$.