We report a high resolution resonant inelastic x-ray scattering investigation of the bilayer manganites La2−2xSr1+2xMn2O7 with x=0.36 and 0.5. The momentum dependence along the crystallographic (110) direction for energy losses 1eV≤ΔE≤15eV has been measured in detail with the data analysis focusing on the energy loss region 1eV≤ΔE≤5eV, which includes a strong peak located at ΔE≈2eV. We observe a clear dispersion of up to 0.5eV in the measured q range, which is direct evidence of the non-local character of this excitation. Further, we found that the intensity in this low energy region strongly depends on both the reduced wave vector q=(h,h,0), h=0.1−0.5, and temperature, i.e. different ordered phases. Results can be explained via an intersite d−d charge transfer excitation, proposed for pseudo-cubic manganites, where the hopping rate is strongly increased (decreased) by ferromagnetic (antiferromagnetic) alignment of neighboring in-plane Mn ion core spins.
@article{arxiv.1007.2283,
title = {d-d Excitations in Bilayer Manganites Probed by Resonant Inelastic X-ray Scattering},
author = {F. Weber and S. Rosenkranz and J. -P. Castellan and R. Osborn and J. F. Mitchell and H. Zheng and D. Casa and J. H. Kim and T. Gog},
journal= {arXiv preprint arXiv:1007.2283},
year = {2011}
}