Phase Diagram of Infinite Layer Praseodymium Nickelate Pr${}_{1-x}$Sr${}_x$NiO${}_2$ Thin Films

Abstract

We report the phase diagram of infinite layer Pr${}_{1-x}$Sr${}_x$NiO${}_2$ thin films synthesized via topotactic reduction from the perovskite precursor phase using CaH${}_2$. Based on the electrical transport properties, we find a doping-dependent superconducting dome extending between $x$ = 0.12 and 0.28, with a maximum superconducting transition temperature $T_{\mathrm{c}}$ of 14 K at $x$ = 0.18, bounded by weakly insulating behavior on both sides. In contrast to the narrower dome observed in Nd${}_{1-x}$Sr${}_x$NiO${}_2$, a local $T_{\mathrm{c}}$ suppression near $x$ = 0.2 was not observed for the Pr${}_{1-x}$Sr${}_x$NiO${}_2$ system. Normal state Hall effect measurements indicate mixed carrier contributions of both electrons and holes, and show a sign change in the Hall coefficient as functions of temperature and $x$, quite similar to that in Nd${}_{1-x}$Sr${}_x$NiO${}_2$. Also similar is the observation of a minimum in the normal state resistivity associated with the superconducting compositions. These findings indicate an infinite layer nickelate phase diagram that is relatively insensitive to the rare-earth element, but suggest that disorder arising from the variations of the ionic radii on the rare-earth site affects the superconducting dome.

17 pages, 3 figures