摘要
After several decades of studies of high-temperature superconductivity, there is no compelling theory for the mechanism yet; however, the spin fluctua…
材料
方法
- inelastic neutron scattering
关键词
本批次暂无数据。
亮点
本批次暂无数据。
结论
本批次暂无数据。
主要论断
- Strong interlayer magnetic exchange coupling exists in La3Ni2O7−δ, with spin excitations centered around 45 meV.
- 证据: 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.
- 证据: No magnetic Bragg peaks were detected in neutron powder diffraction at 10 K,Only diffuse magnetic scattering is observed in INS
研究流程
- neutron powder diffraction for structural refinement — Long-range magnetic order is not detected by diffraction, but structural phases are well characterized.
- 材料: La3Ni2O7−δ powder
- 方法: GPPD at CSNS; Rietveld refinement (GSAS)
- 观察: 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.
- 材料: La3Ni2O7−δ powder
- 方法: INS on MERLIN spectrometer (ISIS)
- 观察: 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.
- 材料: magnetic structure models from literature (µSR, RIXS, NMR)
- 方法: linear spin-wave theory using SpinW
- 观察: 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