Phase diagram of infinite layer praseodymium nickelate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Pr</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Sr</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>NiO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> thin films
Motoki Osada, Bai Yang Wang, Kyuho Lee, Danfeng Li, Harold Y. Hwang
Abstract
We report the phase diagram of infinite layer ${\mathrm{Pr}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{NiO}}_{2}$ thin films synthesized via topotactic reduction from the perovskite precursor phase using ${\mathrm{CaH}}_{2}$. 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 ${\mathrm{Nd}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{NiO}}_{2}$, a local ${T}_{\mathrm{c}}$ suppression near $x=0.2$ was not observed for the ${\mathrm{Pr}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{NiO}}_{2}$ 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 ${\mathrm{Nd}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{NiO}}_{2}$. 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.