d-d Excitations in Bilayer Manganites Probed by Resonant Inelastic X-ray Scattering

Abstract

We report a high resolution resonant inelastic x-ray scattering investigation of the bilayer manganites La${}_{2-2x}$Sr${}_{1+2x}$Mn${}_2$O${}_7$ with $x=0.36$ and $0.5$. The momentum dependence along the crystallographic $(110)$ direction for energy losses $1\mathrm{eV}\le \mathrm{\Delta E}\le 15\mathrm{eV}$ has been measured in detail with the data analysis focusing on the energy loss region $1\mathrm{eV}\le \mathrm{\Delta E}\le 5\mathrm{eV}$, which includes a strong peak located at $\Delta E\approx 2\mathrm{eV}$. We observe a clear dispersion of up to $0.5\mathrm{eV}$ in the measured $\text{q}$ 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 $\text{q}=(h,h,0)$, $h=0.1-0.5$, 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.

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Cited by in corpus (6)

• Resonant inelastic x-ray scattering operators for $t_{2g}$ orbital systems
• Signatures of electronic polarons in La${}_{1-x}$Sr${}_{1+x}$MnO${}_4$ observed by electron energy-loss spectroscopy
• Strongly momentum-dependent screening dynamics in La${}_{0.5}$Sr${}_{1.5}$MnO${}_4$ observed with resonant inelastic x-ray scattering
• Evidence of photo-induced dynamic competition of metallic and insulating phase in a layered manganite
• Excitations across the equilibrium and photoinduced `hidden' states of magnetoresistive manganites
• Momentum dependence in K-edge resonant inelastic x-ray scattering and its application to screening dynamics in CE-phase La${}_{0.5}$Sr${}_{1.5}$MnO${}_4$