Signature of Superconductivity in Pressurized Trilayer-Nickelate Pr₄Ni₃O_10–δ

Abstract The discovery of high-temperature superconductivity in La₃Ni₂O₇ and La₄Ni₃O₁₀ under pressure has garnered extensive attention. Herein, we report systematic investigations on the structure, magnetism, and electrical resistance evolutions of Pr₄Ni₃O_10–δ polycrystalline samples under various pressures. Pr₄Ni₃O_10–δ exhibits density wave transitions on Ni and Pr sublattices at approximately 157.6 and 4.3 K, respectively. The density wave can be progressively suppressed by pressure. A structural transformation from the monoclinic P2₁/a space group to the tetragonal I4/mmm occurs around 20 GPa. An apparent drop in resistance with an evident magnetic field dependence is observed at pressures above 20 GPa, indicating the emergence of superconductivity. The discovery of superconductivity in Pr₄Ni₃O_10–δ broadens the family of nickelate superconductors. Pr₄Ni₃O_10–δ provides a new platform for investigation of the mechanisms of superconductivity in the Ruddlesden–Popper phases of nickelates.