Large upper critical fields and dimensionality crossover of superconductivity in the infinite-layer nickelate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>La</mml:mi><mml:mrow><mml:mn>0.8</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>Sr</mml:mi><mml:mrow><mml:mn>0.2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>NiO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Wei Wei, Wenjie Sun, Yue Sun, Yongqiang Pan, Gangjian Jin, Feng Yang, Yueying Li, Zengwei Zhu, Yuefeng Nie, Zhixiang Shi
Abstract
The recent discovery of superconductivity in nickelates, sharing structural and electronic similarities with cuprates, is crucial for understanding the high-${T}_{c}$ superconducting pairing mechanism. Here, the authors study the ${H}_{c2}$ of a high-quality La${}_{0.8}$Sr${}_{0.2}$NiO${}_{2}$ thin film. Significantly large ${H}_{c2}$ ($\ensuremath{\sim}$ 40 T for $H$ || $c$ and $\ensuremath{\sim}$ 52 T for $H$ || $a\phantom{\rule{0}{0ex}}b$) are obtained. The anisotropy decreases from $\ensuremath{\sim}$10 near ${T}_{c}$ to $\ensuremath{\sim}$1.5 at 2 K, which confirms a crossover from 2D to 3D superconductivity based on the angle dependence of ${H}_{c2}$.