Bulk electronic properties of the bilayered manganiteLa1.2Sr1.8Mn2O7from hard-x-ray photoemission

Abstract

We have performed hard-x-ray photoemission experiments at photon energy close to $6\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$ on the ferromagnetic bilayered manganite ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ across its transition temperature ${T}_{C}$. Differences in both core level and valence band spectra have been observed as a function of temperature: We correlate the energy shift of the O $1s$ peak with a charge-transfer associated with the structural change taking place at the transition. A prominent shoulder on the low binding energy side of the Mn $2p$ core level that is observed below ${T}_{C}$ is tentatively ascribed to increased nonlocal screening in the ordered ferromagnetic phase.