The newly discovered superconductivity in infinite-layer nickelate superconducting films has attracted much attention, largely because their crystalline and electronic structures are similar to those of high-T _c cuprate superconductors. The upper critical field can provide a great deal of information on the subject of superconductivity, but detailed experimental data are still lacking for these films. We present the temperature- and angle-dependence of resistivity, measured under different magnetic fields H in Nd_0.8Sr_0.2NiO₂ thin films. The onset superconducting transition occurs at about 16.2 K at 0 T. Temperature-dependent upper critical fields, determined using a criterion very close to the onset transition, show a clear negative curvature near the critical transition temperature, which can be explained as a consequence of the paramagnetically limited effect on superconductivity. The temperature-dependent anisotropy of the upper critical field is obtained from resistivity data, which yields a value decreasing from 3 to 1.2 with a reduction in temperature. This can be explained in terms of the variable contribution from the orbital limit effect on the upper critical field. The angle-dependence of resistivity at a fixed temperature, and at different magnetic fields, cannot be scaled to a curve, which deviates from the prediction of the anisotropic Ginzburg–Landau theory. However, at low temperatures, the resistance difference can be scaled via the parameter H^β |cosθ| (β = 6–1), with θ being the angle enclosed between the c-axis and the applied magnetic field. As the first detailed study of the upper critical field of nickelate thin films, our results clearly indicate a small anisotropy, and a paramagnetically limited effect, in terms of superconductivity, in nickelate superconductors.

_{新发现的无限层镍酸盐超导薄膜的超导性引起了广泛关注，主要是因为它们的晶体结构和电子结构与高温铜酸盐}超导体 相似。上临界场可以提供大量关于超导主题的信息，但这些薄膜仍然缺乏详细的实验数据。我们展示了电阻率的温度和角度依赖性，在 Nd _0.8 Sr _0.2 NiO ₂的不同磁场H下测量薄膜。起始超导转变发生在 0 T 时约 16.2 K。使用非常接近起始转变的标准确定的与温度相关的上临界场在临界转变温度附近显示出明显的负曲率，这可以解释为对超导性的顺磁限制效应。上临界场与温度相关的各向异性是从电阻率数据中获得的，随着温度的降低，该值会从 3 降低到 1.2。这可以用轨道极限效应对上临界场的可变贡献来解释。在固定温度和不同磁场下，电阻率与角度的关系不能缩放为曲线，这偏离了各向异性金茨堡-朗道理论的预测。然而，在低温下，电阻差可以通过参数来缩放H ^β |cos θ | （β = 6-1），其中θ是c轴和施加的磁场之间的夹角。作为对镍酸盐薄膜上临界场的第一次详细研究，我们的结果清楚地表明了镍酸盐超导体的小各向异性和顺磁限制效应，就超导性而言。