Resistive upper critical fields and anisotropy of an electron-doped infinite-layer cuprate

Abstract

We report a transport study down to 2 K and in high magnetic fields up to 20 T of a highly $c$-axis-oriented epitaxial thin film of electron-doped ``infinite-layer'' cuprate superconductor ${\text{Sr}}_{1\ensuremath{-}x}{\text{La}}_{x}{\text{CuO}}_{2}$ with ${T}_{c}$ of 26 K. A 16 T magnetic field perpendicular to the $ab$ plane of the film completely suppresses superconductivity, even at the lowest temperature. Perpendicular magnetic fields shift the resistive transition to lower temperatures, without significant broadening, in a way similar to that seen in conventional superconductors. The upper critical field ${H}_{c2\ensuremath{\perp}}(T)$ exhibits an almost linear temperature dependence. It is shown that electron-doped infinite-layer cuprate presents three-dimensional superconductivity due to a weaker anisotropy $(\ensuremath{\gamma}=15)$ and smaller ${H}_{c2\ensuremath{\perp}}(T)$ values than the ones of hole-doped cuprates.