Dr. Jennifer Fowlie - Coexistence of magnetism and superconductivity in infinite-layer nickelates

The discovery of superconductivity in Nd0.8Sr0.2NiO2 [1] introduced a new type of layered superconductor that is now known to be a part of a growing family of nickelate superconductors.In the infinite-layer nickelate system, RNiO2, X-ray scattering work has uncovered magnetic excitations that persist across the superconducting dome [2], while neutron scattering on bulk powder samples of the parent compound suggests no long-range magnetic order [3]. This already hints at a difference between the superconducting nickelates and the superconducting cuprates, in which the parent compounds are long-range ordered and the order is quenched with hole doping [4]. In order to probe the intrinsic magnetic character of these compounds, we have carried out low energy muon spin rotation studies on these materials [5]. We observe magnetism that starts to appear at around 150 K and holds down to the lowest temperature measured, which is within the superconducting state. The coexistence of magnetism with superconductivity, as well as the high temperature onset, highlights the nickelates as qualitatively distinct from the doped cuprates. This may be as a result of their proposed multi-orbital nature.

(1] D. Li et al, Nature 572 (2019) 624

[2] H. Lu et al, Science 373 (2021) 213

[3] M. A. Hayward and M. J. Rosseinsky, Solid State Sciences 5 (2003) 839

[4] B. Keimer et al, Nature 518 (2015) 179

[5] J. Fowlie et al, Nature Physics (in press) (2022) arXiv: 2201.11943