{"id":"41a012db-1f17-480c-a18a-b691a90105a1","arxiv_id":"2502.03970","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":4.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":4,"one_line_summary":"Temperature-dependent Raman spectra of Na2Co2TeO6 show phonon anomalies near 17, 30, 70, and 150 K and a broad magnetic continuum, supporting multiple phase transitions and frustrated spin excitations.","lead":"A Raman spectroscopy study of the honeycomb magnet Na2Co2TeO6 reports phonon and magnetic signals tied to four phase transitions between 5 and 300 K, including a possible quantum paramagnetic crossover near 150 K. The work adds a phonon-based fingerprint for Kitaev-spin-liquid candidates that could help identify similar materials.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The 70 K ferroelectric transition is the least secured element of the central claim: it rests on a presumed P6322-to-P63 structural change and on a phonon plateau that could have non-polar origins.","rationale":"The reader's weakest assumption identifies the same load-bearing concern: the ferroelectric transition at ~70 K is the least supported of the four claimed transitions. I agree with a conditional verdict. The Raman anomalies near 30 K, 17 K, and 150 K have independent support from magnetization, specific heat, and neutron-scattering literature, but the 70 K ferroelectric assignment rests on ref [34] and on an ambiguous plateau plus a single weak mode. Because the paper explicitly phrases the structural change as 'suggested' and shows no structural or polarization evidence, the ferroelectric part of the central claim is not established. This does not invalidate the rest of the Raman study; it means the abstract's four-transition claim should be stated with caveats until the P6322-to-P63 transition at 70 K is confirmed. The internal S* onset inconsistency (Section 3.2 and figure captions say below ~50 K, while the Introduction says below ~70 K) further weakens the association of low-frequency modes with the ferroelectric transition, but it is secondary to the missing structural evidence.","tokens_in":20164,"tokens_out":4068,"duration_ms":184821,"concrete_test":"On the same single crystals, measure the Raman spectrum of P* in parallel and crossed polarization configurations from 5 K to 100 K, and combine this with either high-resolution synchrotron X-ray diffraction or dielectric/permittivity measurements across 70 K. If structural refinement shows no P6322-to-P63 transition at ~70 K, or if P* does not follow the polar-mode selection rule expected in P63 and instead responds to a magnetic field like a magnon or two-magnon excitation, then the T_FE assignment should be removed from the central claim. As a complementary check, fit the phonon frequencies and linewidths with a segment-wise model and bootstrap to verify that the slope change at 70 K is statistically significant rather than a visual impression.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's claim of four phase transitions depends on assigning the ~70 K anomaly to a ferroelectric transition. Section 3.2 states that the transition 'is suggested' by a change from P6322 (#182) to polar P63 (#173) and cites ref [34]; no structural, dielectric, or polarization data are presented. The supporting Raman evidence is (i) a nearly constant phonon frequency/FWHM between ~70 K and ~30 K and (ii) the appearance of weak mode P* below ~70 K. A plateau in self-energy parameters is not specific to polar order: it can equally be produced by the onset of short-range magnetic correlations, which are known below ~50 K in this material (ref [31]), competing with anharmonic decay, or by a crossover in available phonon decay channels. P* is a single weak unassigned line; without a symmetry analysis, a magnetic-field response, or a structural measurement, it could be a zone-folded mode from Na/vacancy ordering, a defect/impurity mode, or a magnetic excitation rather than evidence of a polar soft mode. The paper itself hedges in the Introduction, linking the low-frequency modes to 'a structural transition and/or underlying magnetic excitations.' If the 70 K anomaly is not the P6322-to-P63 transition, the abstract's four-transition claim collapses to three transitions plus an uninterpreted plateau, and the suggestion of multiferroic behavior loses its Raman support.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper reports temperature-dependent (5–300 K) and polarization-dependent Raman scattering measurements on single-crystal Na2Co2TeO6, together with DFT-based harmonic phonon calculations. The central claim is that the temperature evolution of phonon self-energies (frequency, linewidth, intensity), the Fano line shape of a low-energy mode S*, the quasi-elastic dynamic Raman susceptibility, and a broad high-frequency continuum reveal four distinct temperature scales: a crossover to a quantum paramagnetic phase near T* ~ 150 K, a ferroelectric transition near TFE ~ 70 K, zigzag antiferromagnetic order near TN ~ 30 K, and a spin-reorientation transition near TSR ~ 17 K. The paper also reports weak modes below ~50–70 K (S* and P*), crystal-field excitations with Kramers-degeneracy lifting, and a temperature-dependent rotation of the polarization pattern of mode P16, which the authors interpret as evidence for tunable optical selection rules across the phase transitions.","tokens_in":20452,"tokens_out":3935,"duration_ms":43183,"significance":"If the four transition temperatures are all correctly identified by Raman spectroscopy, the paper would be a valuable demonstration that a single optical probe tracks the magnetic, polar, and quantum-paramagnetic scales in a Kitaev candidate. The dataset is substantial: spectra over a broad range, multiple phonon modes followed with fine temperature steps near TSR, polarization measurements at four temperatures, and DFT support for mode assignment. The Fano analysis of S*, the Kramers–Kronig treatment of the quasi-elastic response, and the temperature dependence of the magnetic continuum give the manuscript several independent-looking strands of evidence. However, the identification of the 70 K ferroelectric transition is the least secured element of the central claim and is supported only by indirect Raman signatures, while the 17 K spin-reorientation signature is small and presented without statistical quantification. The present evidence is therefore suggestive rather than conclusive for the full four-transition scenario.","major_comments":[{"comment":"The ferroelectric transition at TFE ~ 70 K is the load-bearing claim of the abstract, but the evidence presented is indirect. The text states that the transition 'is suggested' from a P6322 (#182) to polar P63 (#173) structural change and cites reference [34], with no structural, dielectric, or polarization data from this work. The supporting Raman evidence is (i) a near-constant phonon frequency and FWHM between ~70 K and ~30 K and (ii) the appearance of a weak mode P* below ~70 K. A plateau in self-energy parameters is not specific to polar order: it could equally arise from the onset of short-range magnetic correlations, which are known in this material below ~50 K (reference [31]), or from a change in phonon decay channels. Similarly, P* is a single weak unassigned line; without a symmetry analysis, a magnetic-field response, or a structural measurement, it could be a zone-folded mode, a defect/impurity mode, or a magnetic excitation rather than a polar soft mode. If the 70 K anomaly is not the P6322-to-P63 transition, the abstract's four-transition claim reduces to three transitions plus an uninterpreted anomaly, and the multiferroic suggestion loses its Raman support. The authors should either provide additional measurements/analysis that establish the polar nature of the transition or explicitly reframe TFE as an anomaly of unidentified origin.","section":"Section 3.2, Figs. 2 and 3"},{"comment":"There is an internal inconsistency in the onset temperature of the asymmetric low-frequency mode S*. The Abstract and Section 3.1 state that S* appears only below ~50 K, whereas the Introduction states that an asymmetric phonon mode appears below the transition temperature ~70 K and 'potentially corresponds to a structural transition and/or underlying magnetic excitations.' The text also refers separately to P* appearing below ~70 K, but the Introduction's wording conflates the two modes. Since the 70 K structural/polar interpretation depends on which mode appears at which temperature, this ambiguity must be resolved: specify the onset temperatures of S* and P* separately and state explicitly what each mode is claimed to represent.","section":"Section 3.1, Abstract, and Introduction"},{"comment":"The spin-reorientation transition at TSR ~ 17 K is supported by visually identified changes in the slopes of phonon frequency and FWHM versus temperature, but no error bars, derivatives, or statistical tests are presented. For example, Fig. 3(a) shows only small changes in P23–P25 frequencies between 5 and 40 K, and the inset slopes near 17 K are comparable to the scatter of the data. Because TSR is a central element of the four-transition claim, the authors should show uncertainties on the fitted parameters and provide a quantitative criterion (e.g., a slope-break or F-test) that establishes that the changes near 17 K are significant rather than the result of measurement noise or fitting drift.","section":"Section 3.2, Fig. 3(a) and insets of Fig. 2"},{"comment":"The extracted magnetic specific heat Cm is used in Fig. 5(d) as independent confirmation of all four transitions, but the extraction relies on a hydrodynamic relation and a Kramers–Kronig integral with an upper cutoff Omega = 75 cm^-1. No analysis is given of how the result depends on the choice of Omega, on the extrapolation to zero frequency, or on whether the hydrodynamic regime is valid across the full temperature range, including the quantum paramagnetic and ordered phases. The power-law fit chi_dyn(T) ~ T^beta with beta = -0.38 is reported without an uncertainty. The authors should either validate this extraction against a known model or present it as a qualitative indicator rather than as quantitative support for the transition temperatures.","section":"Section 3.4, Eqs. (3) and (4), Fig. 5"}],"minor_comments":[{"comment":"The anharmonic fitting formulae are garbled in the manuscript: the exponentials and parentheses do not render correctly, making it impossible to reproduce the fits from the text alone. Please rewrite them cleanly with all factors defined.","section":"Equations (1) and (2)"},{"comment":"The Raman spectrum at 5 K is reported to contain 'more than twenty-seven' modes, but Table I lists 25 named modes including S* and P*. Please reconcile the count and ensure that every observed mode is either assigned or explicitly stated to be unassigned.","section":"Section 3.1 and Table I"},{"comment":"The rotation of the P16 polar plot is interesting, but the text states that 'solid red lines are the fitted curves' only for Fig. 6(a); Fig. 7 does not show any fitted curves or uncertainties. Please provide fits for the rotated maxima and define the parameter Psi (rotation angle) quantitatively.","section":"Section 3.5, Fig. 7"},{"comment":"The y-axis label 'log10 Cm' in the main text conflicts with the caption's description of Cm, and the scale is otherwise not defined. Please clarify whether the plotted quantity is log(Cm) and give units or normalization.","section":"Figure 5(d)"},{"comment":"Reference [27] is incomplete ('Supplemental Material of___'), and several cited articles (e.g., references [45]–[47]) are listed in the Introduction but appear not to be discussed in the body text. Please match the citation list to the in-text callouts.","section":"References"}],"recommendation":"major_revision","confidential_remarks":"The paper contains a rich experimental dataset and the broad claims are likely of interest to the condensed-matter community, but the ferroelectric-transition identification needs either new experimental support or a substantially weakened claim. The lack of error bars and statistical testing also affects the TSR assignment. These issues are fixable within a revision, so I am not recommending rejection."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The one thing to know: this is a solid but incremental Raman study of Na2Co2TeO6. The combined full-temperature plus polarization dataset is new, and the self-energy anomalies near 150 K, 30 K, and 17 K are consistent with prior bulk work. The paper does not resolve the Kitaev question, and it does not claim to.\n\nWhat it does well: the temperature-dependent phonon frequencies and linewidths are tracked over a wide range with a fine 2 K interval below 40 K. The 17 K spin-reorientation signature, though small, is shown in the P23–P25 frequency slopes. The Fano analysis of S* and the polarization rotation of P16 are genuinely interesting observations that go beyond earlier Raman reports. The DFT phonon table is a useful point of reference, even if it is not the main event.\n\nThe soft spots are real but not fatal. The 70 K ferroelectric transition is the weakest link: the paper admits it is \"suggested\" from a presumed P6322 to P63 change, cites ref [34], and offers a phonon plateau plus a weak P* mode as Raman support. A plateau in self-energy parameters is not specific to polar order, and P* is unassigned. If that structural transition is not at 70 K, the abstract's four-transition claim loses one pillar. The paper's own language lets it survive, but the authors should have been more explicit that this is borrowed from the literature rather than evidenced here. Also, the S* onset temperature is stated as ~50 K in the abstract and ~70 K in the introduction; that should be fixed. There are no error bars or significance tests on the slope changes; for a characterization paper that is a shortcoming but not a disqualifier.\n\nThe citation pattern is fair. The prior Raman work on NCTO is acknowledged, and the new elements—full temperature range, P16 rotation, combined self-energy anomalies—are legitimately extensions. The paper is honest about what is already known.\n\nBottom line: this deserves a serious referee. The physics is plausible, the data are real, and the weak ferroelectric claim is framed as a suggestion rather than a definitive conclusion. I would send it to review, ask for the S* inconsistency to be fixed, and ask the authors to either soften the 70 K claim or provide direct structural/dielectric evidence. A reader working on Kitaev candidates or phonon-magnetic coupling will get value from this.","headline":"A careful Raman characterization of NCTO with plausible multi-transition signatures; the 70 K ferroelectric claim is the softest piece, but the paper hedges appropriately and the core phonon-anomaly narrative holds up.","tokens_in":21016,"tokens_out":1068,"would_cite":true,"duration_ms":12691,"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":"Temperature-dependent Raman scattering on the cobalt honeycomb magnet Na2Co2TeO6 reports four transitions in phonon self-energies: a quantum paramagnetic crossover near 150 K, a ferroelectric transition near 70 K, zigzag antiferromagnetic…","keywords":["Na2Co2TeO6","Kitaev spin liquid","Raman spectroscopy","phonon self-energy","zigzag antiferromagnetism","spin reorientation","ferroelectric transition","magnetic continuum"],"falsifier":"A temperature-dependent x-ray or neutron diffraction study across 70 K, or a second-harmonic-generation or dielectric measurement, would settle whether the $P6_{3}22$-to-$P6_{3}$ polar transition actually occurs at $T_\\mathrm{FE}$. If no polar structural change or dielectric anomaly appears near 70 K while the Raman plateau remains, the ferroelectric assignment would be ruled out; conversely, an applied magnetic field that removes the 17 K spin-reorientation signature while leaving the 70 K phonon plateau unchanged would confirm the two are distinct transitions.","tokens_in":19943,"feed_emoji":"🧲","tokens_out":14397,"duration_ms":111043,"temperature":0.7,"pith_summary":"This paper argues that temperature-dependent Raman scattering on the honeycomb cobalt magnet Na2Co2TeO6 records four distinct temperature scales in one set of measurements: a crossover into a quantum paramagnetic phase near 150 K, a proposed ferroelectric transition near 70 K, zigzag antiferromagnetic order near 30 K, and a spin reorientation near 17 K. The evidence lies in the phonon mode frequencies, linewidths, and intensities, which change slope at each of these temperatures. The paper also reports an asymmetric low-frequency excitation near 63 cm-1 that appears below about 50 K and is assigned to magnetic excitations other than magnons, along with a broad high-frequency magnetic continuum whose temperature dependence suggests frustrated spin dynamics. The reason to care is that a single optical probe would then track all of the relevant ordering and crossover scales of a putative Kitaev spin-liquid candidate, and the phonon anomalies well above the magnetic ordering temperature point to nontrivial spin excitations developing before long-range order sets in.","feed_headline":"One Raman run maps four phase transitions in a cobalt honeycomb magnet","feed_subtitle":"Phonon shifts trace magnetic order, spin reorientation, polar order, and a quantum paramagnetic crossover.","key_machinery":"The load-bearing object is the temperature-dependent phonon self-energy, extracted by fitting Raman peaks to Lorentzian profiles and following the peak frequency $\\omega(T)$ and full width at half maximum $\\Gamma(T)$. Above 150 K these are described by a three- and four-phonon anharmonic model; deviations and slope changes below that temperature are the signatures of each transition. The Fano profile $I(\\delta)\\propto(1+q^{-1}\\delta)^2/(1+\\delta^2)$ quantifies the coupling of the discrete $S^*$ mode to an underlying continuum, with $1/q$ as the coupling strength. Quasi-elastic scattering is converted through the Raman response and a Kramers-Kronig relation into a dynamic susceptibility and an estimate of the magnetic specific heat, both of which also show changes at the four temperatures.","core_discovery":"The central claim is that the renormalized self-energy parameters—mode frequency $\\omega(T)$ and full width at half maximum $\\Gamma(T)$—of Raman-active phonons in Na2Co2TeO6 show reproducible slope changes at $T^*\\sim150$ K, $T_\\mathrm{FE}\\sim70$ K, $T_\\mathrm{N}\\sim30$ K, and $T_\\mathrm{SR}\\sim17$ K, and that these mark, respectively, a crossover from a pure paramagnet to a quantum paramagnetic phase, a ferroelectric transition in which the structure is suggested to change from $P6_{3}22$ to polar $P6_{3}$, the onset of long-range zigzag antiferromagnetic order, and a spin reorientation inside the ordered phase. In the low-frequency spectrum an asymmetric Fano-shaped mode $S^*$ near 63 cm$^{-1}$ appears below about 50 K and is assigned to magnetic excitations distinct from magnons; its Fano asymmetry parameter changes slope at $T_\\mathrm{SR}$ and $T_\\mathrm{N}$, tying it to the magnetic order. A broad continuum between roughly 330 and 1400 cm$^{-1}$ loses intensity sharply above $T_\\mathrm{N}$ and shows a further slope change near $T^*$, which the paper reads as evidence of frustrated magnetic interactions in the quantum paramagnetic regime. Polarization-dependent data show one phonon mode, P16, whose intensity pattern rotates by nearly 90 degrees between 5 K and 300 K, indicating that the underlying phase changes alter the Raman selection rules.","pith_inferences":["If the four-temperature picture holds, Raman spectroscopy could serve as a quick screening tool for other $d^7$ honeycomb Kitaev candidates, with phonon self-energy anomalies flagging candidate spin-liquid regimes before neutron or thermodynamic studies are undertaken.","The 70 K assignment is the most exposed part of the paper; a dedicated structural or dielectric probe would either verify the polar $P6_{3}$ phase or require reinterpreting the phonon plateau as short-range magnetic correlations rather than ferroelectric order.","The temperature-dependent rotation of the P16 polarization pattern, if confirmed as an order-parameter-like effect, could become a sensitive optical probe of symmetry changes; a microscopic model connecting the rotation angle to the proposed polar or magnetic order would be a testable extension.","Measuring the magnetic-field dependence of the $S^*$ mode would test whether it is the same non-magnon excitation as the roughly 55 cm$^{-1}$ excitation reported for this compound, and whether its Fano coupling tracks the spin-reorientation transition."],"forward_implications":["A single optical probe can separate the four temperature scales in Na2Co2TeO6, making Raman spectroscopy a practical diagnostic for phase boundaries in honeycomb cobaltates.","Phonon renormalization beginning near 150 K implies spin-phonon coupling and nontrivial spin excitations exist well above the magnetic ordering temperature, consistent with short-range correlated or frustrated spin physics.","The broad magnetic continuum and its temperature dependence support the presence of frustrated magnetic interactions in the quantum paramagnetic phase and invite comparison with fractionalized-excitation scenarios in Kitaev candidates.","The Fano mode $S^*$ at 63 cm$^{-1}$ provides a distinct low-energy excitation tied to the magnetic order, useful for probing how disorder or magnetic fields renormalize non-magnon excitations.","The near-90-degree rotation of the P16 polarization pattern between 5 K and 300 K shows that the Raman selection rules in this material are tunable across the underlying phase transitions."],"supporting_citations":[{"why":"This reference supplies the reported 70-75 K ferroelectric transition and the P6322-to-P63 polar structural change that the paper adopts for the TFE assignment.","marker":"[34]"},{"why":"This reference reports the zigzag antiferromagnetic ground state with anisotropic correlation lengths and short-range correlations below about 50 K, supporting the T* crossover and magnetic ordering picture.","marker":"[31]"},{"why":"This reference reports a significant thermal Hall effect in NCTO near 150 K, independent evidence of nontrivial excitations that the phonon anomalies are compared with.","marker":"[32]"},{"why":"This reference reports a roughly 55 cm-1 magnetic excitation distinct from magnons that splits under magnetic field, which the paper uses to assign the asymmetric S* mode.","marker":"[48]"},{"why":"This reference provides neutron-scattering evidence on excitations in ordered and paramagnetic states of NCTO, grounding the magnetic-continuum interpretation.","marker":"[61]"},{"why":"This reference documents low-temperature spin-orbit phase behavior and zigzag antiferromagnetic ordering near 25-30 K in NCTO.","marker":"[19]"},{"why":"This reference reports the magnetic properties of NCTO including the spin reorientation near 17 K, anchoring the TSR assignment.","marker":"[29]"},{"why":"This reference gives the theoretical d7 pseudospin exchange framework predicting that Heisenberg exchange is weak relative to Kitaev coupling in cobalt compounds, the basis for expecting Kitaev physics in NCTO.","marker":"[10]"}],"fun_headline_variants":["Raman phonons expose four phase transitions in a cobalt honeycomb","One Raman run maps four phase transitions in a Kitaev candidate","Phonon self-energy traces magnetic, polar, and quantum transitions","Cobalt honeycomb's Raman signature reveals multiple phase changes","Quantum paramagnetic crossover seen via Raman phonon shifts"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The 70 K ferroelectric transition is inferred from a plateau in phonon frequency and linewidth between roughly 70 K and 30 K plus the appearance of a weak mode $P^*$, assuming these reflect the reported $P6_{3}22$-to-$P6_{3}$ polar structural change; the paper presents no structural, dielectric, or polarization data of its own, so if that structural change does not occur at 70 K, the ferroelectric-transition claim loses its Raman support.","fun_headline_variants_meta":{"raw":{"variants":["Raman phonons expose four phase transitions in a cobalt honeycomb","One Raman run maps four phase transitions in a Kitaev candidate","Phonon self-energy traces magnetic, polar, and quantum transitions","Cobalt honeycomb's Raman signature reveals multiple phase changes","Quantum paramagnetic crossover seen via Raman phonon shifts"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000222,"raw_usage":{"total_tokens":1556,"prompt_tokens":1147,"completion_tokens":409,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":763,"completion_tokens_details":{"reasoning_tokens":324}},"tokens_in":763,"tokens_out":409,"duration_ms":5013,"temperature":1.0,"reasoning_tokens":324,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-09T00:01:20.058231+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A temperature-dependent x-ray or neutron diffraction study across 70 K, or a second-harmonic-generation or dielectric measurement, would settle whether the $P6_{3}22$-to-$P6_{3}$ polar transition actually occurs at $T_\\mathrm{FE}$. If no polar structural change or dielectric anomaly appears near 70 K while the Raman plateau remains, the ferroelectric assignment would be ruled out; conversely, an applied magnetic field that removes the 17 K spin-reorientation signature while leaving the 70 K phonon plateau unchanged would confirm the two are distinct transitions.","supporting_citations":[{"cited_title":"Yang et al., Significant thermal Hall effect in the 3d cobalt Kitaev system 22 Na2Co2TeO6, Phys","cited_arxiv_id":null,"evidence_quote":"This reference supplies the reported 70-75 K ferroelectric transition and the P6322-to-P63 polar structural change that the paper adopts for the TFE assignment."},{"cited_title":"Lefrançois et al., Magnetic properties of the Honeycomb oxide Na2Co2TeO6, Phys","cited_arxiv_id":null,"evidence_quote":"This reference reports the zigzag antiferromagnetic ground state with anisotropic correlation lengths and short-range correlations below about 50 K, supporting the T* crossover and magnetic ordering picture."},{"cited_title":"Yao and Y","cited_arxiv_id":null,"evidence_quote":"This reference reports a significant thermal Hall effect in NCTO near 150 K, independent evidence of nontrivial excitations that the phonon anomalies are compared with."},{"cited_title":"Kumar, D","cited_arxiv_id":null,"evidence_quote":"This reference reports a roughly 55 cm-1 magnetic excitation distinct from magnons that splits under magnetic field, which the paper uses to assign the asymmetric S* mode."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"This reference provides neutron-scattering evidence on excitations in ordered and paramagnetic states of NCTO, grounding the magnetic-continuum interpretation."},{"cited_title":"Singh and P","cited_arxiv_id":null,"evidence_quote":"This reference documents low-temperature spin-orbit phase behavior and zigzag antiferromagnetic ordering near 25-30 K in NCTO."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"This reference reports the magnetic properties of NCTO including the spin reorientation near 17 K, anchoring the TSR assignment."}],"review_version":1}