# LSCO magnetic excitations: persistence within a measured window

Follow the momentum range, linewidth and intensity corrections before drawing a conclusion about superconducting pairing.

## Review scope

Selected journal text, Figure 3 and supplementary fitting, normalization and spectral-weight sections. The sample-thickness discrepancy remains unresolved.

- Author self-review; no independent scientific acceptance or raw-data refitting.
- The journal main text and supplementary Table I disagree on two sample thicknesses. No silent reconciliation is applied.
- Study 3 adds limited coverage to studies 2, 5 and 9; six inherited series studies remain pending.

## Persistence has a momentum window

Dean and colleagues find broadened magnetic excitations in LSCO up to $x=0.40$. Their reported fitted window is $\mathbf Q=(0.18\text{–}0.40,0)$ in reciprocal lattice units. It complements neutron measurements near $(0.5,0.5)$. Similar dispersion and comparable integrated intensity in this window do not establish conservation across the whole Brillouin zone.

Evidence: experiment. Source relationship: direct-support. Sources: dean-journal.

## Widths and intensities need their corrections

The resolution is 130 meV **HWHM**, not FWHM. Fits include a thermal factor and resolution convolution. Unresolved phonon/multispin scattering contributes an estimated 15% overestimate to width and intensity. Supplementary intensity corrections include a changed incident flux and a 0.78 factor for the nominally thicker films; instrumental instability enters the uncertainty.

Evidence: experiment. Source relationship: direct-support. Sources: dean-journal, dean-supplement.

## An unresolved sample-thickness discrepancy

The main-text grouping assigns approximately 53 nm to $x=0.16$ and 99 nm to $x=0.26$. Supplementary Table I instead lists $97\pm3$ nm and $52\pm3$ nm, respectively. The normalization discussion follows the former grouping. These records are not reconciled here; the corrected intensities have not been independently reproduced.

Evidence: experiment. Source relationship: direct-support. Sources: dean-journal, dean-supplement.

## What the spectral-fraction estimate assumes

The quoted 27% spectral fraction comes from an undoped spin-wave calculation. Extending its persistence with doping assumes comparable scaling along an unmeasured diagonal direction.

Evidence: experiment. Source relationship: direct-support. Sources: dean-supplement.

## Use spectral evidence to constrain a pairing model

Editorially, persistence of an excitation is one constraint on a pairing theory. It cannot by itself select a unique interaction or explain the transition temperature. Compare the relevant momentum, energy and sample conditions, rather than treating an integrated signal as a complete pairing kernel.

Evidence: experiment. Source relationship: context-for-editorial-analysis. Sources: dean-supplement.

## Coverage within the inherited research series

This note covers study 3. [Interface localization](/scwiki/library/cuprate-interface-layer-order) covers studies 2 and 9; [THz conductivity](/scwiki/library/bilbro-thz-fluctuation-window) covers study 5. Six studies and additional cross-topic comparisons remain pending.

Each source keeps its own uncertainty and access limits. The source-note merge remains partial; a linked paper does not mean every claim has been independently reviewed.

Evidence: experiment. Source relationship: context-for-editorial-analysis. Sources: .

## Sources

dean-journal: M. P. M. Dean and colleagues. [Persistence of magnetic excitations in La2−xSrxCuO4 from the undoped insulator to the heavily overdoped non-superconducting metal](https://markdean.info/assets/pdf/dean2013persistence.pdf). journal-article; Published online 2013-08-04; Nature Materials 12, 1019–1023 (2013), journal-formatted PDF hosted by the author. Selected pages 1–4; Figure 3 inspected. Raw data not refitted.

dean-supplement: M. P. M. Dean and colleagues. [Supplementary Information to Persistence of magnetic excitations in LSCO](https://markdean.info/assets/pdf/dean2013persistence_supp.pdf). journal-article; Associated article published online 2013-08-04; Journal Supplementary Information, author-hosted 14-page PDF. Selected pages 6 and 9–12; pixels 6, 10 and 12 inspected. Thickness discrepancy unresolved.

## Editorial corrections

- Coverage of the measurement: Retain the measured momentum window and the assumptions behind extrapolation.
- Confidence in intensity comparison: Keep normalization uncertainty and the unresolved primary-source discrepancy visible.

## Provenance

papers/CROSS_D3_D11_BozovicInterface.md; commit 0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf; SHA-256 8f299055adac85ea95c5dca9a35c6939305162fa1c0f36e4a8f6d58211a7be83; partial-merge. Coverage: Dean magnetic-excitation comparison only. Other interface and THz evidence has separate notes; remaining CROSS claims require review.

papers/library/Bozovic_Cuprate-Interface-Series_READING_NOTES.md; commit 0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf; SHA-256 6c0b3484dbfe9831b95e8f1ad578c2889e9c88b5e25c6954bb09160df741f0ee; partial-merge. Coverage: Study section 3: Dean magnetic excitations only. Other study coverage is documented separately; six series studies remain pending.

Original concise synthesis and editorial analysis. The PDFs retain a publisher copyright notice; no open reuse license is asserted and no paper figures are reproduced.

Note ID: dean-lsco-magnetic-excitations. Revision: b388fdbf09cd08339b08.