Tensile strain effect on superconductivity and thermally activated vortex motion in $\mathrm{Sr}_{1-x}\mathrm{Eu}_{x}\mathrm{Cu}\mathrm{O}_{2+y}$ thin films

Abstract We report the superconducting properties of tensile-strained infinite-layer cuprate Sr 1− x Eu x CuO 2+ y thin films fabricated on KTaO 3 substrates via molecular beam epitaxy. The doping-dependent superconducting phase diagram shows an optimal doping level of $x\ \sim $ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>x</mml:mi> <mml:mspace/> <mml:mo>∼</mml:mo> </mml:math> 0.184 and a broader dome shifting to higher doping range due to reduced intralayer hopping and enhanced interlayer magnetic coupling. The characteristic of two-dimensional superconductivity is observed by Berezinskii-Kosterlitz-Thouless transition and the angle-resolved magnetoresistance measurements. Moreover, the temperature-dependent upper critical field and thermally-activated vortex motion under the in-plane and out-of-plane magnetic fields exhibit strong anisotropy, which further reveal the anisotropic nature of the superconductivity in infinite-layer cuprates.