We investigate high-energy spin excitations in hole-doped La₂-ₗCaₗCuO₄-⏓ films across a broad Ca doping range x = 0. 05-0. 50 using resonant inelastic x-ray scattering (RIXS). Polarization analysis and incident-photon energy detuning measurements confirm the persistence of collective paramagnon excitations up to x = 0. 50. Consistent with previous studies on other cuprate families, we observe a pronounced crossover near x = 0. 15, where paramagnon spectral weight is transferred to incoherent spin-flip excitations associated with the particle-hole continuum. The overall behavior of paramagnons in LCCO resembles that in other hole-doped cuprates and appears insensitive to the persistence of superconductivity at high doping levels in LCCO - up to at least x = 0. 50, as demonstrated in prior work. These findings support the view that high-energy magnetic excitations probed by RIXS are not a major contributor to superconducting pairing, in line with theories of spin-fluctuation mediated superconductivity.
Hameed et al. (Mon,) studied this question.