Pressure-induced monotonic enhancement of Tc to over 30 K in superconducting Pr0.82Sr0.18NiO2 thin films

Abstract

The successful synthesis of superconducting infinite-layer nickelate thin films with the highest T_c ≈ 15 K has ignited great enthusiasm for this material class as potential analogs of the high-T_c cuprates. Pursuing a higher T_c is always an imperative task in studying a new superconducting material system. Here we report high-quality Pr_0.82Sr_0.18NiO₂ thin films with T_c^onset ≈ 17 K synthesized by carefully tuning the amount of CaH₂ in the topotactic chemical reduction and the effect of pressure on its superconducting properties by measuring electrical resistivity under various pressures in a cubic anvil cell apparatus. We find that the onset temperature of the superconductivity, T_c^onset, can be enhanced monotonically from ~17 K at ambient pressure to ~31 K at 12.1 GPa without showing signatures of saturation upon increasing pressure. This encouraging result indicates that the T_c of infinite-layer nickelates superconductors still has room to go higher and it can be further boosted by applying higher pressures or strain engineering in the heterostructure films.

Despite much recent effort, the highest reported T_c of the infinite-layer nickelates remains lower than 15 K. Here, the authors apply pressure to Pr_0.82Sr_0.18NiO₂ thin films and observe a monotonic increase of T_c to 31 K at 12.1 GPa, an increase that does not level off with increasing pressure.