{"schemaVersion":"1.0","revision":"414f1e850a9ed04cee70","note":{"id":"yang-eu-nickelate-reentrance","title":"Eu-doped nickelates: re-entrance without a settled pairing mechanism","summary":"Separate sample-specific zero resistance, diamagnetic screening and resistance-contour criteria in Sm/Ca/Eu infinite-layer films; keep exchange compensation, magnetic order and pairing symmetry as distinct questions.","kind":"research-note-and-cross-topic-analysis","modifiedAt":"2026-10-19T00:19:22.329110+00:00","aliases":["Yang","Eu-doped infinite-layer nickelate","Sm0.95-xCa0.05EuxNiO2","SCE","field reentrant superconductivity","Jaccarino Peter","磁场再入超导"],"evidenceTypes":["experiment","theory"],"relatedCodes":["D5","D15","G3","G5","H7","H9"],"review":{"checkedAt":"2026-10-19","scope":"Selected passages and figures in author manuscript arXiv:2508.14666v3 (25 April 2026), compared with the publisher abstract. The complete final published text has not been checked.","limitations":["Author self-review, not independent scientific review or a reproduction of the transport measurements.","The later author version is not assumed identical to the final journal article; full final text, correction history, calibration and raw-data analysis remain open.","Resistance-contour criteria, zero resistance and screening are different observables. None alone settles the magnetic structure or pairing symmetry."]},"sections":[{"id":"material-and-version","title":"Identify the material and the version","markdown":"Yang and colleagues study Sm0.95−xCa0.05EuxNiO2 (SCEₓ), an infinite-layer nickelate film series with fixed nominal Ca substitution. It is not Eu-substituted bilayer La3Ni2O7. The measured Eu valence is mixed and varies with composition, so nominal x is not a direct count of identical Eu²⁺ moments.\n\nThis note reads the revised author manuscript dated 25 April 2026. The journal article was published online on 23 April 2026. The publisher abstract supports the broad re-entrance report, but access to that abstract does not establish equivalence of all final and author-version figures. The separate Nd/Eu nickelate study discussed in G3 and G5 concerns another material series; its magnetic interpretation cannot simply be transferred here.","evidenceType":"experiment","sourceIds":["yang-author-v3"],"sourceRelationship":"direct-support"},{"id":"sample-conditions","title":"Keep each field scale with its sample and criterion","markdown":"The selected author text and Figure 2 distinguish the following observations. Fields are perpendicular to the film plane (H∥c) for these comparisons.\n\n| Sample | Temperature or protocol | Reported observation | Interpretation boundary |\n| --- | --- | --- | --- |\n| SCE0.34, about 54 unit cells | 2 K transport | Zero resistance returns above about 6.23 T | Recovery field, not a universal upper critical field |\n| Same SCE0.34 specimen | Temperature sweeps at fixed field | Mutual-inductance screening at 9 and 12 T; absent at 3 T | Supports the superconducting interpretation; no bulk volume fraction is inferred here |\n| SCE0.32 | 3 K transport | Resistance returns to zero near 13.04 T | Not the upper boundary of the high-field phase |\n| SCE0.32 | 1.7 K transport | High-field zero resistance persists above about 32 T | Different temperature from the 13.04 T statement |\n\nThese temperatures describe measurement conditions, not interchangeable transition temperatures. Figure 3 instead marks open-circle phase boundaries using 0.5Rn, with Rn the high-field normal-state resistance. Those contours must not be relabeled zero-resistance boundaries. No material-Tc record is created from this table.","evidenceType":"experiment","sourceIds":["yang-author-v3"],"sourceRelationship":"direct-support"},{"id":"angles-and-version-correction","title":"Angular behavior and an unresolved inherited number","markdown":"The angle θ is measured from the film normal. The angular maps use different temperatures: 4.2 K for x=0.33 and 0.36, 1.5 K for x=0.38, and 0.3 K for x=0.40. Their changing angular windows cannot support a universal assertion that in-plane re-entrance is absent. The manuscript also distinguishes intermediate-doping compensation-like behavior from stronger deviations at x=0.40.\n\nThe inherited notes attribute persistence to 45 T at 0.3 K to SCE0.36. That exact sample–temperature–field tuple was not verified in the selected v3 pages. Extended Data Figure 9 labels SCE0.36 at 4.2 K and SCE0.40 at 0.3 K; it also has a caption saying “up to 45 T” although its upper panels extend to 60 T. These version and panel details require resolution before the inherited tuple is used as a current verified result. A measurement ceiling would in any case provide a bound, not a measured high-field endpoint.","evidenceType":"experiment","sourceIds":["yang-author-v3"],"sourceRelationship":"direct-support"},{"id":"compensation-and-magnetism","title":"What the magnetic evidence can and cannot establish","markdown":"Nonlinear Hall response after linear-background subtraction and hysteretic magnetoresistance motivate magnetic explanations. They do not by themselves identify uniform ferromagnetism, its volume fraction, or a particular pairing state. The v3 discussion explicitly leaves long-range magnetic order and its structure undetermined.\n\nThe authors fit a WHH-based model including orbital and Pauli pair breaking, spin-orbit scattering and an exchange field. Compensation partially describes intermediate compositions; the fitted exchange fields and scattering parameters remain phenomenological. An empirical factor of two in a Brillouin-function argument improves some fits but is not universal and does not adequately describe x=0.40. Neither this adjustment nor analogy with other re-entrant systems proves spin-triplet pairing.","evidenceType":"theory","sourceIds":["yang-author-v3"],"sourceRelationship":"direct-support"},{"id":"cross-topic-use","title":"Use the result across the Wiki","markdown":"D5 supplies the material-family context; D15 separates substitution, scattering and magnetism; G3 and G5 distinguish re-entrance from a demonstrated compensation mechanism. For H7 and H9, superconducting recovery fields must not become Hall-sign-reversal or anomalous-Hall threshold fields. This note reports no extracted ordinary Hall coefficient.\n\nA stronger scientific assessment still needs version-resolved final figures, criterion and noise-floor checks, sample calibration and local magnetic probes. The present review neither fits the deposited source-data files nor certifies an intrinsic bulk phase or unique microscopic mechanism.","evidenceType":"hypothesis","sourceIds":["yang-author-v3"],"sourceRelationship":"context-for-editorial-analysis"}],"sources":[{"id":"yang-author-v3","title":"Field re-entrant superconductivity in Eu-doped infinite-layer nickelates","authors":"Mingwei Yang and colleagues","url":"https://arxiv.org/abs/2508.14666v3","publicationStatus":"preprint","date":"2026-04-25","dateLabel":"Author version revised","version":"arXiv:2508.14666v3; first submitted 20 August 2025; later author manuscript associated with the published article","checkedAt":"2026-10-19","scope":"Selected pages 2, 4–8, 12–14; Figure 2 (page 19), Figure 3 (page 20), and Extended Data Figure 9 (page 30) inspected. Full final-version equivalence and raw-data reproduction unverified.","doi":"10.48550/arXiv.2508.14666","licenseUrl":"https://creativecommons.org/licenses/by/4.0/","licenseLabel":"CC BY 4.0 (author version)"},{"id":"yang-journal","title":"Field re-entrant superconductivity in Eu-doped infinite-layer nickelates","authors":"Mingwei Yang and colleagues","url":"https://doi.org/10.1038/s41586-026-10547-y","publicationStatus":"journal-article","date":"2026-04-23","dateLabel":"Published online","version":"Nature 653, 1052–1059 (2026); publisher abstract only checked","checkedAt":"2026-10-19","scope":"Previously accessible publisher abstract and publication metadata. Complete final text is subscription restricted; the later author manuscript supplies the detailed selected evidence in this note.","doi":"10.1038/s41586-026-10547-y","licenseUrl":null,"licenseLabel":null}],"provenance":[{"path":"papers/CROSS_D5_D15_Yang2026.md","commit":"0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf","sha256":"33970aef30ac6c132f95921ae2553d6662681ba11301ae6daf97d4a0a056d6a6","disposition":"merge-into","repository":"JackZH26/jzis-superconductivity","coverage":"Whole source-note disposition; the primary scientific review remains limited to the stated scope."},{"path":"papers/library/Yang_Eu-IL-Nickelate-Reentrant-SC_READING_NOTES.md","commit":"0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf","sha256":"7c02489fdb5faf31238beec381fadf8a49c3e9a9fbb33426f7a2011b216fbd47","disposition":"merge-into","repository":"JackZH26/jzis-superconductivity","coverage":"Whole source-note disposition; the primary scientific review remains limited to the stated scope."}],"corrections":[{"issue":"Magnetic order and pairing","inherited":"Ferromagnetic superconductivity and a mixed compensation/triplet explanation stated too strongly.","resolution":"Retain the observed transport and screening, while magnetic order, pairing symmetry and a unique mechanism remain unresolved."},{"issue":"Angular dependence","inherited":"In-plane re-entrance universally excluded.","resolution":"Retain sample-specific angle and temperature dependence, including the broader windows in higher-doping specimens."},{"issue":"Unverified inherited 45 T tuple","inherited":"SCE0.36 at 0.3 K assigned a 45 T persistence result.","resolution":"Do not carry this tuple as verified by v3: selected later panels use SCE0.36 at 4.2 K and SCE0.40 at 0.3 K. Final/version reconciliation remains open."},{"issue":"Threshold and contour criteria","inherited":"Recovery fields and measurement ceilings can be read as upper critical fields.","resolution":"Keep 6.23 T and 13.04 T with their specific samples and temperatures; distinguish zero resistance from the 0.5Rn contour criterion."},{"issue":"Screening and Hall scope","inherited":"Meissner/bulk proof or Hall thresholds inferred from re-entrant transport.","resolution":"Describe mutual-inductance diamagnetic screening without deriving bulk volume fraction; do not invent Hall coefficients or reversal fields."}],"rights":"Original editorial synthesis adapted from Mingwei Yang and colleagues' CC BY 4.0 author manuscript, linked below. Wording, organization and cross-topic analysis have changed; no source figures are reproduced. The journal version and third-party materials retain their own stated rights.","revision":"9f57bca48151c4275ba8"}}