Resonant X-ray scattering spectroscopy study on bilayer nickelates La₂PrNi₂O₇

The discovery of high-temperature superconductivity in bilayer nickelates has raised great effort towards addressing key ingredients for superconductivity. A central player is magnetic correlations, which are intimately linked to superconductivity in other high T_c systems. Studies in the bulk materials suggest a seemingly competitive relationship between spin density wave (SDW) order and the superconductivity --- upon suppressing the density wave order at high pressure, superconductivity emerges. In thin films, strong SDW order has been found across a large range of substrate strain, with a characteristic wavevector Q_SDW = (0.25, 0.25) and a transition temperature around 150 K, comparable to the bulk. In this talk, I will present our X-ray scattering spectroscopy study of superconducting La₂PrNi₂O₇ thin films. The electronic structure and the magnetic ground state properties will be discussed.