Source zotero
Authors Not available in this batch.
arXiv / Publisher https://www.sciencedirect.com/science/article/pii/S2095927324005164
PDF Not available in this batch.
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Published 2024-10-29
Research paradigm Experimental
Sample form Unknown

Summary

After several decades of studies of high-temperature superconductivity, there is no compelling theory for the mechanism yet; however, the spin fluctua…

Materials

Methods

  • inelastic neutron scattering

Keywords

Not available in this batch.

Highlights

Not available in this batch.

Conclusions

Not available in this batch.

Main claims

  • Strong interlayer magnetic exchange coupling exists in La3Ni2O7−δ, with spin excitations centered around 45 meV.
    • Evidence: Spin excitations are observed in INS spectra with a broad feature near 45 meV,Linear spin-wave theory with interlayer coupling SJ_perp ≈ 60 meV reproduces the spectral weight
  • Static long-range magnetic order is absent, but short-range spin correlations persist.
    • Evidence: No magnetic Bragg peaks were detected in neutron powder diffraction at 10 K,Only diffuse magnetic scattering is observed in INS

Workflow

  • neutron powder diffraction for structural refinement — Long-range magnetic order is not detected by diffraction, but structural phases are well characterized.
    • Materials: La3Ni2O7−δ powder
    • Methods: GPPD at CSNS; Rietveld refinement (GSAS)
    • Observations: no new peaks or clear magnetic intensity at 10K; coexistence of Amam (56%) and Fmmm (41%) phases; refined lattice parameters and atomic positions
  • inelastic neutron scattering (INS) measurement — Spin excitations in La3Ni2O7−δ are broad and centered at ≈45 meV, indicating strong magnetic fluctuations.
    • Materials: La3Ni2O7−δ powder
    • Methods: INS on MERLIN spectrometer (ISIS)
    • Observations: diffuse magnetic scattering at low T; broad spin excitation centered around 45 meV; non-dispersive spectrum
  • linear spin-wave theory simulation — The observed spin excitations are consistent with either single spin-charge stripe or double spin stripe order, but not double spin-charge stripe.
    • Materials: magnetic structure models from literature (µSR, RIXS, NMR)
    • Methods: linear spin-wave theory using SpinW
    • Observations: simulations with reduced exchange coupling (SJ≈2-4 meV, SJ_perp≈57-67 meV) give spectral weight around 45 meV; double spin-charge stripe gives too narrow mode