Field re-entrant superconductivity in Eu-doped infinite-layer nickelates
/ Authors
Mingwei Yang, Jiayin Tang, Xianfeng Wu, Heng Wang, Wenjing Xu, Haoliang Huang, Zhicheng Pei, W. Meng, Guangli Kuang, Mingwei Yang
and 12 more authors
Jinfeng Xu, Sixia Hu, Junfeng Wang, Liang Li, Zerui Wang, Chuanying Xi, Li Pi, Qingyou Lu, Ziqiang Wang, Qikun Xue, Zhuoyu Chen, Danfeng Li
/ Abstract
Intertwined superconducting and magnetic orders may give rise to exotic quantum phases, including field-induced and re-entrant superconductivity. However, such magnetism-enhanced superconductivity has remained elusive in superconductors with higher transition temperatures. While infinite-layer nickelates represent a new class of unconventional superconductors, the impact of rare-earth magnetism on superconducting properties remains largely unexplored. Here, we show that Eu-doped infinite-layer nickelate Sm$_{0.95-x}$Ca$_{0.05}$Eu$_x$NiO$_2$ exhibits a magnetic-field-induced re-entrant superconducting phase in the Eu-rich over-doped regime. Zero-resistance transport and high-field diamagnetic screening confirm the superconducting nature of this phase, which emerges after the initial suppression of low-field superconductivity and remains robust across a broad range of temperatures, fields and field orientations. In the same doping range, we observe nonlinear Hall transport and hysteretic magnetoresistance, indicating the unconventional nature of the re-entrant behaviour. While partially consistent with a compensation mechanism between the Eu-derived exchange field and the applied field, our data reveal pronounced deviations from this model at the highest-doping levels. Our findings establish infinite-layer nickelates as a fertile platform for exploring magnetically driven high-field superconductivity in strongly correlated oxides.
Journal: Nature