Spin excitations in superconducting single-crystalline La4Ni3O10

The captivating realm of nickelates, characterized by the multiple oxidation states of nickel, has been a subject of intense interest. A breadth of fascinating materials has been uncovered, including superconducting infinite-layer nickelates, and the bilayer Ruddlesden-Popper La3Ni2O7 superconductor under pressure. Recently, pressure-induced bulk superconductivity has been observed in trilayer La4Ni3O10. In contrast to the weak magnetism in La3Ni2O7, La4Ni3O10 exhibits a strong magnetic order at ambient pressure. External pressure suppresses this magnetic order and induces superconductivity at 30 K. These results suggest an unconventional superconducting mechanism in which magnetism may play an important role. We propose to perform Ni L-edge RIXS on single-crystalline La4Ni3O10 to study the spin excitations and determine the effective exchange couplings. This information is crucial to understanding the magnetism and its relationship with superconductivity in nickelates.