{"id":"2594671f-87e0-46a7-ad73-e9e7e8597c26","arxiv_id":"2508.02415","paper_version":2,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":5.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":5,"one_line_summary":"Mn3Sn(0001) epitaxial films show a 0.9% spin Hall angle, a 44.4 (hbar/e) Ohm^-1 cm^-1 spin Hall conductivity, 72% interface transparency, and a spin diffusion length above 15 nm at room temperature.","lead":"Epitaxial films of the antiferromagnet Mn3Sn and Mn3Sn/permalloy stacks were measured for their ability to generate and carry spin currents. The paper reports a 0.9% spin Hall angle, a spin Hall conductivity near 44.4 (hbar/e) Ohm^-1 cm^-1, a spin-mixing conductance of 28.52 nm^-2, about 72% interface spin transparency, and a spin diffusion length above 15 nm at room temperature.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Abstract omits the control measurements needed to attribute the FMR voltages to spin pumping and the inverse spin Hall effect; without them, the quoted spin-Hall, interfacial, and diffusion-length parameters are unverified.","rationale":"The supplied full text is a mojibake rendition and includes a header from arXiv:2508.02414, so my review is necessarily limited to the abstract and the Pith reader's report. I agree with the reader's weakest-assumption identification: the interpretation of the measured DC voltages and linewidth changes as spin-pumping-driven spin-charge conversion is the foundation on which all quantitative conclusions rest. I considered whether another concern was more load-bearing, such as internal consistency of the quoted parameters or physical plausibility of a 15 nm spin diffusion length in an epitaxial antiferromagnet, but none of these could be checked against the corrupted text, and none is logically prior to the signal-identification problem. I therefore treat the parasitic contamination concern as the single load-bearing issue. The proposed test is the standard, decisive one: angular symmetry under magnetization reversal separates the odd inverse-spin-Hall contribution from the even rectification and thermoelectric contributions, and the power and thickness dependences test the spin-transport model. Because the concern is real but the evidence needed to evaluate it is absent from the reviewed material, the correct verdict remains unverified. I am not moving the reader's verdict.","tokens_in":10690,"tokens_out":6118,"duration_ms":83033,"concrete_test":"Perform a control experiment on the same Mn3Sn(0001)/Py stack under FMR: rotate the in-plane magnetic field through 360 degrees and record the DC voltage for several RF powers. Fit the angular dependence to a superposition of an odd component (V(phi) = -V(-phi), expected for the inverse spin Hall effect from a spin current polarized along the magnetization) and an even component (spin rectification and thermoelectric effects). Require that the odd component be linear in RF power and scale monotonically with Mn3Sn thickness, saturating for thicknesses beyond the claimed spin diffusion length; if the odd component is absent or does not survive subtraction of rectification and thermal baselines, the extracted interfacial and bulk spin-transport parameters are not supported.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim reduces to the assertion that the DC voltage recorded under ferromagnetic resonance in Mn3Sn(0001)/Ni81Fe19 is produced by spin pumping from the permalloy followed by spin-to-charge conversion in Mn3Sn. Every headline number - the 0.9% spin Hall angle, the 44.4 (hbar/e) ohm^-1 cm^-1 spin Hall conductivity, the 28.52 nm^-2 spin-mixing conductance, the 72% transparency, and the >15 nm spin diffusion length - is extracted from that identification. The abstract does not display the control measurements that would establish this identification: no in-plane field-angle sweep, no RF-power sweep, no frequency dependence, no reference sample, and no thickness series is shown. In metallic bilayers, the measured FMR-induced DC voltage can be dominated by spin rectification from anisotropic magnetoresistance or the anomalous Hall effect, and by thermoelectric voltages from RF heating; each of these has a different symmetry and scaling. If any of these parasitic contributions are present in the reported data, the extracted spin Hall angle, spin-mixing conductance, transparency, and spin diffusion length are not the intrinsic values claimed. The full text supplied here is corrupted and contains a header from arXiv:2508.02414, so I cannot determine whether the experiments contain the necessary controls. The concern is therefore not an internal contradiction but an unverified prerequisite.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript reports an experimental study of spin pumping and spin-to-charge conversion in epitaxial (0001)-oriented Mn3Sn thin films and Mn3Sn/Ni81Fe19 heterostructures. From ferromagnetic-resonance measurements the authors extract a spin Hall angle of 0.9%, a nearly isotropic in-plane spin Hall conductivity of about 44.4 (hbar/e) ohm^-1 cm^-1 at room temperature, a spin-mixing conductance of 28.52 nm^-2, an interfacial spin transparency of about 72%, and a spin diffusion length exceeding 15 nm. The spin Hall conductivity is attributed to a combination of intrinsic and extrinsic contributions, with support from first-principles calculations. The abstract is the only readable part of the supplied manuscript; the full text is corrupted and partly replaced by text from another arXiv submission, so the technical content cannot be independently checked.","tokens_in":10975,"tokens_out":3764,"duration_ms":42670,"significance":"If the reported parameters are correct, the work would establish epitaxial Mn3Sn(0001) as a promising room-temperature antiferromagnetic spin source and spin-transport medium, with a spin Hall conductivity in a useful range, a high interfacial spin transparency, and a long spin diffusion length. The combination of topological Weyl semimetal physics with practical spin-pumping measurements is of clear interest to the spintronics community. The central quantitative claims, however, rest on an experimental identification that is not visible in the supplied version of the manuscript; the paper's value therefore depends on the controls and raw-data analysis that a revised, readable version must provide.","major_comments":[{"comment":"The supplied full text is corrupted to the point of illegibility and contains a header from a different arXiv paper, 'arXiv:2508.02414v1 [cs.LG] 4 Aug 2025'; as a result, the methods, raw data, sample details, and extraction equations for theta_SH, sigma_SH, G_updown, T, and lambda_sd cannot be checked. This is load-bearing because every headline number derives from identifying the measured DC voltage under ferromagnetic resonance with spin-pumping-driven spin-to-charge conversion in Mn3Sn; without a readable description of that identification, the central claims are not verifiable.","section":"Full text (post-abstract)"},{"comment":"The abstract reports no control measurements that would separate the spin-pumping-induced inverse spin Hall voltage from spin rectification (AMR/AHE) and thermoelectric voltages: no in-plane field-angle sweep, RF-power scaling, frequency dependence, reference sample lacking Mn3Sn, or Mn3Sn thickness series is shown. Since the extracted spin Hall angle, spin-mixing conductance, transparency, and spin diffusion length all depend on that separation, these parameters are unestablished until such controls are provided.","section":"Abstract"},{"comment":"The headline precision is not supported by the abstract: sigma_SH = 44.4 (hbar/e) ohm^-1 cm^-1 and G_updown = 28.52 nm^-2 are quoted without uncertainties, and the claim of a nearly isotropic in-plane spin Hall conductivity requires an angular or multi-direction measurement that is not described. The authors should provide error bars and define the averaging procedure used for 'nearly isotropic'.","section":"Abstract"},{"comment":"The attribution of the spin Hall conductivity to 'a combination of intrinsic and extrinsic contributions' cannot be evaluated from the abstract, and distinguishing intrinsic from extrinsic mechanisms normally requires temperature, disorder, or thickness-dependent data; the full text, which might contain such data, is unreadable in the supplied version.","section":"Abstract"}],"minor_comments":[{"comment":"The notation '~44.4' combines an approximate tilde with a precise-looking number; please report the fitted value and its uncertainty consistently.","section":"Abstract"},{"comment":"The manuscript must be reset from the original source before any technical review is possible; the current version contains garbled text and an arXiv header from an unrelated submission.","section":"Full text"},{"comment":"The statement that the spin diffusion length 'exceeds 15 nm' should be accompanied by the method of determination (for example, a thickness series or an oblique spin-pumping geometry) and by the uncertainty bound.","section":"Abstract"},{"comment":"The abstract mentions 'limitations' of Mn3Sn without specifying them; the conclusions should state which parameters (for example, conductivity, transparency, or magnetization dynamics) limit practical efficiency.","section":"Abstract"}],"recommendation":"major_revision","confidential_remarks":"The version of the manuscript supplied for review is largely unreadable, and I cannot tell whether this is a submission error or a pipeline artifact; either way, the technical evaluation cannot proceed on the current text. I would be willing to re-review a clean version that includes the control measurements and data analysis requested in the major comments."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Quick take: this is a routine but useful materials-parameter paper. The abstract claims that epitaxial (0001) Mn3Sn films generate and transmit spin currents at room temperature, with a spin Hall angle of 0.9%, a nearly isotropic spin Hall conductivity of about 44.4 (hbar/e) ohm^-1 cm^-1, a spin-mixing conductance of 28.52 nm^-2, an interfacial transparency of ~72%, and a spin diffusion length above 15 nm. If those numbers are right, Mn3Sn joins the short list of documented antiferromagnetic spin sources with a long spin diffusion length. The 0.9% spin Hall angle is modest compared with heavy metals, so the impact stays inside the spintronics subfield rather than restructuring it. The measurement approach is established, so the new content is material parameters, not a new mechanism.\n\nWhat the paper does well, as far as the abstract shows: it combines spin-pumping FMR with spin-to-charge conversion measurements on an epitaxial, noncollinear antiferromagnet, and it explicitly mentions intrinsic and extrinsic contributions discussed alongside first-principle calculations. That is the right level of engagement for this kind of study. The citation pattern is not visible, so I cannot judge that.\n\nThe soft spot is exactly what the stress-test note flags: all the headline numbers rest on identifying the measured FMR voltage as spin-pumping-driven spin-to-charge conversion in Mn3Sn. The abstract does not display the control measurements that would rule out spin rectification, thermoelectric voltages, or other parasitic contributions. That is a real concern, but it is also a standard one in FMR spin-pumping papers, and the abstract says the study is systematic. I cannot check whether the controls are in the full paper because the supplied text is corrupted and interleaved with a header from a different arXiv submission. So this is an unverified prerequisite, not an internal contradiction. Minor point: the abstract gives no error bars, so the six significant figures on the spin-mixing conductance and transparency seem optimistic.\n\nWho should read it: people working on antiferromagnetic spintronics or spin-orbit torques in Mn3Sn. If the controls are in place, this is a solid reference data point. The paper deserves a serious referee time, but the referee must check the symmetry and scaling of the measured DC voltage against the parasitic candidates.\n\nMy recommendation: send it to peer review, but ask the authors to either show the control sweeps or soften the parameter claims. I would not cite it myself until I can read the full methods and see the linewidth and voltage data.","headline":"A plausible material-characterization paper on Mn3Sn spin pumping, but the supplied full text is corrupted so the numbers are unverifiable from what I can see.","tokens_in":11480,"tokens_out":1183,"would_cite":false,"duration_ms":16963,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Epitaxial Mn3Sn(0001) films act as room-temperature antiferromagnetic spin-current sources, with a 0.9% spin Hall angle and a spin diffusion length above 15 nm.","keywords":["Mn3Sn","noncollinear antiferromagnet","spin pumping","spin Hall effect","spin diffusion length","spin-mixing conductance","Weyl semimetal","spintronics"],"falsifier":"A control experiment on a Mn3Sn film with no permalloy layer, or with a nonmagnetic spacer inserted at the interface, should show a vanishing spin-pumping voltage and no resonance linewidth enhancement. Likewise, an angular scan of the voltage against the applied field direction should follow the inverse-spin-Hall symmetry; observing a substantial voltage with the wrong angular dependence would falsify the spin-pumping interpretation.","tokens_in":10539,"feed_emoji":"🧲","tokens_out":5928,"duration_ms":68631,"temperature":0.7,"pith_summary":"The paper aims to show that the noncollinear antiferromagnet Mn3Sn can do two jobs at once: generate a spin current from an adjacent ferromagnet and carry that spin current through its own bulk, converting it to a charge voltage. Working with epitaxial (0001)-oriented films, the authors measure a spin Hall angle of 0.9% and a nearly isotropic in-plane spin Hall conductivity of about $44.4\\,(\\hbar/e)\\,\\Omega^{-1}\\,\\mathrm{cm}^{-1}$ at room temperature, and they attribute the effect to both intrinsic Berry-curvature and extrinsic scattering contributions. In Mn3Sn/Ni81Fe19 bilayers they extract a spin-mixing conductance of $28.52\\,\\mathrm{nm}^{-2}$ and an interfacial spin transparency near 72%, with a spin diffusion length above 15 nm. If these numbers hold, Mn3Sn is one of the few antiferromagnets that can serve as a room-temperature spin source, spin conductor, and spin-charge converter in one film.","feed_headline":"Antiferromagnetic Mn3Sn sources spin currents at room temperature","feed_subtitle":"Spin Hall angle 0.9%, interfacial transparency 72%, spin diffusion length above 15 nm at room temperature.","key_machinery":"The central object is the Mn3Sn(0001)/Ni81Fe19 bilayer measured by spin-pumping ferromagnetic resonance. The permalloy layer is driven to resonance; its decaying magnetization pumps a spin current into Mn3Sn, broadening the resonance line (giving the spin-mixing conductance) and producing a voltage via the inverse spin Hall effect in Mn3Sn (giving the spin Hall angle and conductivity). Thickness-dependent measurements yield the spin diffusion length. The noncollinear Kagome spin order and Weyl-node Berry curvature are invoked as the intrinsic source of the large spin Hall conductivity.","core_discovery":"The paper's central claim is that epitaxial (0001)-oriented Mn3Sn acts as an efficient spin-current generator and spin-transport medium at room temperature. Spin pumping from a Ni81Fe19 layer injects a spin current across a Mn3Sn(0001)/Ni81Fe19 interface; the inverse spin Hall effect in Mn3Sn converts it into a charge voltage. The authors extract a spin Hall angle of 0.9%, a nearly isotropic spin Hall conductivity of about $44.4\\,(\\hbar/e)\\,\\Omega^{-1}\\,\\mathrm{cm}^{-1}$, a spin-mixing conductance of $28.52\\,\\mathrm{nm}^{-2}$, an interfacial spin transparency of about 72%, and a spin diffusion length exceeding 15 nm. They interpret the spin Hall conductivity as the sum of intrinsic Berry-curvature and extrinsic contributions, supported by first-principles calculations. The conclusion is that Mn3Sn is suitable as a topological antiferromagnetic material for spin transport and conversion.","pith_inferences":["One implication the authors leave implicit: the same Mn3Sn layer could simultaneously serve as spin generator, spin conductor, and spin detector, so a single antiferromagnetic film might replace the ferromagnet/heavy-metal bilayer in some spintronic functions.","A testable extension would be to measure the spin Hall conductivity as a function of Mn3Sn thickness and temperature; if the extrinsic contribution dominates in thinner films, the effective spin Hall angle should shrink with decreasing thickness, which would be a direct fingerprint of the proposed intrinsic-plus-extrinsic decomposition.","Comparing the voltage amplitude with a reference sample using a known spin Hall metal such as platinum, under identical spin-pumping conditions, would place the 0.9% angle on an absolute scale and reveal whether interface oxidation, rather than the Mn3Sn bulk, limits the observed transparency."],"forward_implications":["A room-temperature antiferromagnet that both sources and conducts spin currents could replace heavy-metal layers in spin-orbit-torque devices, since Mn3Sn adds no net magnetization to the stack.","The near-isotropic in-plane spin Hall conductivity means the spin-charge conversion efficiency does not depend strongly on crystal orientation, simplifying device fabrication.","The spin diffusion length above 15 nm allows spin information to travel through a sizeable Mn3Sn layer, enabling spintronic devices that use Mn3Sn as the spin-transport channel.","The coexistence of intrinsic and extrinsic contributions implies the spin Hall angle may be tunable by alloying, strain, or thickness without redesigning the interface."],"supporting_citations":[],"fun_headline_variants":["Mn3Sn thin films pump spin currents at room temperature","Topological Mn3Sn converts spin to charge with 0.9% Hall angle","Antiferromagnetic Mn3Sn sources spin currents","Mn3Sn spin diffusion length exceeds 15 nm at room temperature","Room temperature spin currents from antiferromagnetic Mn3Sn"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The results rest on the assumption that the measured electrical signals come from spin currents pumped into Mn3Sn and not from other voltage effects at the interface or in the magnetic layer; if that separation is incomplete, all the quoted efficiencies are unreliable.","fun_headline_variants_meta":{"raw":{"variants":["Mn3Sn thin films pump spin currents at room temperature","Topological Mn3Sn converts spin to charge with 0.9% Hall angle","Antiferromagnetic Mn3Sn sources spin currents","Mn3Sn spin diffusion length exceeds 15 nm at room temperature","Room temperature spin currents from antiferromagnetic Mn3Sn"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.002302,"raw_usage":{"total_tokens":8936,"prompt_tokens":1055,"completion_tokens":7881,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":671,"completion_tokens_details":{"reasoning_tokens":7794}},"tokens_in":671,"tokens_out":7881,"duration_ms":63248,"temperature":1.0,"reasoning_tokens":7794,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T04:57:43.623021+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A control experiment on a Mn3Sn film with no permalloy layer, or with a nonmagnetic spacer inserted at the interface, should show a vanishing spin-pumping voltage and no resonance linewidth enhancement. Likewise, an angular scan of the voltage against the applied field direction should follow the inverse-spin-Hall symmetry; observing a substantial voltage with the wrong angular dependence would falsify the spin-pumping interpretation.","supporting_citations":[],"review_version":1}