论文标题
通过运输测量值揭示的物理特性，超导nd $ _ {0.8} $ sr $ _ {0.2} $ nio $ _ {2} $薄膜
Physical properties revealed by transport measurements on superconducting Nd$_{0.8}$Sr$_{0.2}$NiO$_{2}$ thin films
论文作者
论文摘要
新发现的无限层镍超导膜中的超导性引起了很多关注，因为它们的结晶和电子结构与高$ T_C $ t_c $ cuprate超导体相似。上临界场可以提供有关超导性的大量信息，但是这些电影中仍然缺乏详细的实验数据。在这里，我们介绍了在ND $ _ {0.8} $ sr $ _ {0.2} $ niO $ _ {2} $薄膜下测得的电阻率（$ h $）（$ h $）的电阻率的温度和角度依赖性。发作超导转变发生在0 t的大约16.2 k处。通过使用非常接近发作过渡的标准确定的温度依赖性上部临界场在临界过渡温度附近显示出明显的负曲率，这被解释为对超导对超导率的参数效果的结果。从电阻率数据获得了上临界场的温度依赖性各向异性，该数据可在降低温度的情况下从3降低到1.2。这可以通过轨道极限对上临界场的效应产生的可变贡献来解释。固定温度和不同磁场的角度依赖性电阻率不能缩放到一条曲线，这偏离了各向异性金茨堡 - 兰道理论的预测。但是，在低温下，磁场的电阻率增加可以通过参数$ h^β| \cosθ| $（$ 1 <β<6 $），而$θ$则在$ c $轴和施加的磁场之间包含角度。作为第一个关于镍薄膜上部临界场的详细研究，我们的结果清楚地表明，超导性在镍超导体中的各向异性和顺磁性有限。
The newly found superconductivity in infinite-layer nickelate superconducting films has attracted much attention, because their crystalline and electronic structures are similar to high-$T_c$ cuprate superconductors. The upper critical field can provide much information on superconductivity, but detailed experimental data are still lacking in these films. Here we present temperature and angle dependence of resistivity measured under different magnetic fields ($H$) in Nd$_{0.8}$Sr$_{0.2}$NiO$_{2}$ thin films. The onset superconducting transition occurs at about 16.2 K at 0 T. Temperature dependent upper critical fields determined by using a criterion very close to the onset transition show a clear negative curvature near the critical transition temperature, which is explained as the 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 lowering temperature. This can be explained by a variable contribution from the orbital limit effect on upper critical field. The angle dependent resistivity at a fixed temperature and different magnetic fields cannot be scaled to one curve, which deviates from the prediction of the anisotropic Ginzburg-Landau theory. However, at low temperatures, the increased resistivity by magnetic field can be scaled by the parameter $H^β|\cosθ|$ ($1<β<6$) with $θ$ the angle enclosed between $c$-axis and the applied magnetic field. As the first detailed study on the upper critical field of the nickelate thin films, our results clearly indicate a small anisotropy and paramagnetically limited effect of superconductivity in nickelate superconductors.
