A superconducting praseodymium nickelate with infinite layer structure

A variety of nickel oxide compounds have long been studied for their manifestation of various correlated electron phenomena. Recently, superconductivity was observed in nanoscale infinite layer nickelate thin films of Nd${}_{0.8}$Sr${}_{0.2}$NiO${}_2$, epitaxially stabilized on SrTiO${}_3$ substrates via topotactic reduction from the perovskite precursor phase. Here we present the synthesis and properties of PrNiO${}_2$ thin films on SrTiO${}_3$. Upon doping in Pr${}_{0.8}$Sr${}_{0.2}$NiO${}_2$, we observe superconductivity with a transition temperature of 7-12 K, and robust critical current density at 2 K of 334 kA/cm${}^2$. These findings indicate that superconductivity in the infinite layer nickelates is relatively insensitive to the details of the rare earth 4$f$ configuration. Furthermore, they motivate the exploration of a broader family of compounds based on two-dimensional NiO${}_2$ planes, which will enable systematic investigation of the superconducting and normal state properties and their underlying mechanisms.