Thermodynamic evidence for high-field bulk superconductivity in UTe$_{2}$

UTe$_{2}$ has been of great interest in recent years due to its proposed unconventional magnetic field re-enforced spin-triplet superconducting phases persisting at fields far above the simple Pauli limit for $H\parallel b$. A high-field phase also emerges above $40\,\mathrm{T}$ within the field polarized paramagnetic phase when $H$ is applied close to the $[011]$ direction. Here we present thermodynamic evidence of the field stabilized superconducting phases in UTe$_{2}$ via angular dependent magnetocaloric measurements in pulsed magnetic fields. We observe a pronounced heating effect during the metamagnetic transition when $H$ is applied along the $[011]$ direction, within the high field phase, indicative of vortex movement in a bulk superconducting state. Our results support the phase diagram established by previous electrical transport measurements. A more subtle feature observed around $15\,\mathrm{T}$ supports a phase transition between two separate superconducting states when the field orientation is within a few degrees of the $b$ axis.