Effects of rare-earth magnetism on the superconducting upper critical field in infinite-layer nickelates
Bai Yang Wang, Tiffany C. Wang, Yu‐Te Hsu, Motoki Osada, Kyuho Lee, Chunjing Jia, Caitlin Duffy, Danfeng Li, Jennifer Fowlie, M. R. Beasley, Thomas Devereaux, I. R. Fisher, N. E. Hussey, Harold Y. Hwang
Abstract
The search for superconductivity in infinite-layer nickelates was motivated by analogy to the cuprates, and this perspective has framed much of the initial consideration of this material. However, a growing number of studies have highlighted the involvement of rare-earth orbitals; in that context, the consequences of varying the rare-earth element in the superconducting nickelates have been much debated. Here, we show notable differences in the magnitude and anisotropy of the superconducting upper critical field across the La-, Pr-, and Nd-nickelates. These distinctions originate from the 4 f electron characteristics of the rare-earth ions in the lattice: They are absent for La 3+ , nonmagnetic for the Pr 3+ singlet ground state, and magnetic for the Nd 3+ Kramer’s doublet. The unique polar and azimuthal angle-dependent magnetoresistance found in the Nd-nickelates can be understood to arise from the magnetic contribution of the Nd 3+ 4 f moments. Such robust and tunable superconductivity suggests potential in future high-field applications.