{"id":"12c37593-12f0-47ab-a04a-aea0fa3e1423","arxiv_id":"2412.08113","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":8,"one_line_summary":"Mixing TmBa2Cu3O7 with 20% NdBa2Cu3O7 and annealing at 980 C produces grains up to about 0.1 mm, raising the magnetic hysteresis width while leaving the pinning mechanism unchanged.","lead":"Russian researchers mixed two ceramic superconductors and heated them so that large grains up to 0.1 mm grew in the product. The bigger grains trap more magnetic flux, and the team argues this comes from grain size, not from stronger vortex pinning.","discovery_kind":"new_method","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Attribution of high ΔM to grain size rests on D≈11 μm from loop asymmetry, but the reported lognormal distribution gives a volume-weighted grain-size scale of ≈100–400 μm; unless the 0.1 mm grains are shown not to carry current, the inferred jc and 'pinning unchanged' conclusion are not established.","rationale":"The paper's direct observations—SEM grain sizes up to 0.1 mm, XRD phase content, and enhanced ΔM—are credible and potentially interesting. The causal claim, however, requires that the enhancement of ΔM be due to grain size while pinning is unchanged. That conclusion is reached via D≈11 μm from the asymmetry formula. The internal inconsistency with the broad lognormal distribution is the soft spot: in any critical-state model of independent grains, the measured loop width is weighted by volume and grain size, so a number-weighted D cannot simply be inserted into jc=3ΔM/D. The reader's verdict already flags the D model; this stress test sharpens it by showing that the D value is inconsistent with the very grain-size distribution the paper uses to support the claim. The fix is straightforward: replace the single D with a distribution-weighted critical-state analysis, or demonstrate directly that the 0.1 mm grains carry current at the 0.1 mm scale. Until then, conditional acceptance is appropriate: the observation stands, but the interpretation is not settled.","tokens_in":9832,"tokens_out":21084,"duration_ms":201940,"concrete_test":"Compute the volume-weighted mean grain size from the published lognormal parameters (λ=5.5 μm, σ=1.1): E[D^4]/E[D^3] ≈ 380 μm, and check the reported 36% volume fraction for D>100 μm under D^3 weighting (it should be ≈75%, revealing a weighting inconsistency). Then refit the 4.2 K M(H) loop with a critical-state model that sums Bean-model grain contributions over this distribution with one common intragrain jc and the 68 wt% superconducting fraction. If the best-fit jc is more than ~10× lower than the reported value, the reported jc and the 'pinning unchanged' comparison are invalid. If the fit only works when current loops are capped at ≈11 μm, the 0.1 mm grains are not the current-carrying entities and the grain-size attribution fails. A complementary direct check is magneto-optical imaging of the polished surface at 4.2 K to see whether screening currents span the 0.1 mm grains.","verdict_should_be":"UNCHANGED","load_bearing_attack":"Section 4 estimates jc=3ΔM/D using D≈11 μm obtained from the loop-asymmetry formula of Ref. [33] and equates this with the average grain size from the lognormal fit (λ=5.5 μm, σ=1.1, number-weighted mean 10.4 μm). This equation is the entire bridge between the measured ΔM and the paper's central causal claim. For a granular superconductor in the critical state, the measured ΔM is a volume-weighted sum of per-grain contributions, so the relevant current-loop scale is not automatically the number-weighted mean grain size. For the quoted lognormal parameters, E[D^4]/E[D^3] ≈ 380 μm, i.e., an order of magnitude larger than 11 μm; even using the authors' reported 36% volume fraction for grains >0.1 mm, the effective scale is far above 11 μm. Two internally inconsistent possibilities follow. First, if the 0.1 mm grains carry currents over their full size, D is ~10–30× larger and jc is correspondingly lower than the reported 7.2×10^6 A/cm², invalidating the 'comparable jc, unchanged pinning' comparison. Second, if the actual current loops are only ~11 μm, then the 0.1 mm grains do not contribute as coherent loops and cannot be the stated cause of the high ΔM. The paper provides no evidence distinguishing these cases, and the single D value is presented without error bars or field dependence despite the strong sensitivity of the asymmetry formula near ΔM/2|Mmax| ≈ 1.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The manuscript reports a solid-state route in which a TmBa2Cu3O7-d ceramic is annealed for 1 h at 980 °C (above its peritectic temperature) together with 20 vol% refractory NdBa2Cu3O7-d seed grains, yielding a 1-2-3 material with grains up to ~0.1 mm (largest ~140 μm). XRD Rietveld refinement gives 68 wt% 1-2-3 phase, 18 wt% BaCuO2, and 14 wt% Tm2BaCuO5. The grain size is described by a lognormal distribution (λ = 5.5 μm, σ = 1.1; number-weighted mean 10.4 μm), with grains above 100 μm forming 0.4% of the count but, per the authors, 36% of the volume. Tc = 91.3 K. The magnetization width ΔM is several times larger than in reference polycrystalline REBCO, and the trapped field is Btr = 0.167 T at 4.2 K. Using the loop-asymmetry formula of Ref. [33] with λ = 150 nm, the authors obtain a current-loop scale D ≈ 11 μm, compute jc = 3ΔM/D (up to 7.2×10^6 A/cm² at 4.2 K), and from Dew-Hughes scaling (p = 0.8, q = 3.2 at 80 K) and an exponential jc(T) dependence conclude that the pinning mechanism is unchanged relative to standard solid-state material. The central causal claim is that the enhanced ΔM is mainly due to the increased grain size.","tokens_in":10213,"tokens_out":22848,"duration_ms":219672,"significance":"If the attribution holds, the paper gives a clean demonstration that in granular RE-123 ceramics the magnetization width and trapped field are set by the grain/current-loop scale rather than by stronger pinning, and the seeding route is a simple, reproducible way to grow ~0.1 mm grains by solid-state methods. The strengths are the direct measurements: SEM resolves grains up to 140 μm; Rietveld refinement quantifies the secondary phases; ΔM and Btr are measured observables; and the lognormal parameters and pinning fit parameters (jc(0), T0, p, q) are explicit, making the analysis reproducible and falsifiable. The authors also state their assumptions (Nd123 cores in the large grains; the Ref. [33] loop model) candidly. The significance is limited by the model-dependence of the attribution: D is the only bridge between measured ΔM and the conclusion 'larger grains, unchanged pinning', and its value is not yet established for a two-phase ceramic with a strongly skewed grain-size distribution.","major_comments":[{"comment":"The paper's central causal claim ('The increase in grain size in the synthesized samples is the main reason for the high values of ΔM', Abstract; 'These larger grains are responsible for the record values of ΔM', Conclusion) rests entirely on identifying the current circulation scale D ≈ 11 μm with the average grain size. For a collection of decoupled grains in the critical state, the measured ΔM is a volume-weighted sum of per-grain contributions ΔM_i ∝ jc · D_i, so the relevant scale is the volume-weighted mean grain size, not the number-weighted mean. For the reported lognormal parameters (λ = 5.5 μm, σ = 1.1, number mean 10.4 μm), the volume-weighted scale E[D^4]/E[D^3] is about 380 μm, more than an order of magnitude above 11 μm, and the paper itself states that grains above 100 μm occupy 36% of the volume. There are then two internally inconsistent possibilities. First, if the 0.1 mm grains do carry currents over their full size, D is ~10–30 times larger than 11 μm and the reported jc = 7.2×10^6 A/cm² (and the quantitative comparison with polycrystalline YBCO used to support 'pinning unchanged') is correspondingly too high by the same factor. Second, if the actual current loops are only ~11 μm, then the large grains do not contribute coherently and cannot be the stated cause of the high ΔM. The manuscript provides no evidence distinguishing these cases. Please either (i) compute ΔM with a critical-state model that sums per-grain contributions using the measured size distribution and show that the 36%-volume large-grain component accounts for the observed ΔM with the same jc as the reference materials, or (ii) provide a direct determination of the current-loop scale (e.g., magneto-optical imaging or magnetization of size-separated powders).","section":"Sec. 4 (Discussion), jc = 3ΔM/D and D ≈ 11 μm"},{"comment":"The loop-asymmetry formula of Ref. [33] is imported without validation for the present material, and three specifics make this load-bearing. (a) The formula is extremely sensitive near the operating point because the denominator approaches zero as the ratio ΔM/2|Mmax| approaches unity; for example, with the loop parameters evident in Fig. 4 (ΔM ~ 30–35 emu/g, |Mmax| ~ 16–18 emu/g), a few percent change in the ratio changes D by tens of percent, yet no error bars or sensitivity analysis are given for D. (b) The formula is applied at a single field value even though ΔM varies with H, and a single D is then used for all fields and temperatures, although the effective loop scale in a granular system need not be field-independent. (c) The sample contains 32 wt% of non-superconducting phases (BaCuO2, Tm2BaCuO5) and a strongly skewed grain-size distribution, conditions under which the single-scale formula of Ref. [33] has not been tested. Because all of the 'pinning unchanged, grain size enhanced' reasoning passes through this formula, its accuracy is central to the paper's claim. Please report D with propagated uncertainty, test the formula against a full critical-state calculation using the measured grain distribution, or justify why a single-scale extraction is adequate for this two-phase ceramic.","section":"Sec. 4, loop-asymmetry formula D ≈ 2λ/[1 − (ΔM/2|Mmax|)^(1/3)]"},{"comment":"The reported lognormal parameters and the stated volume fraction of large grains do not appear mutually consistent. Interpreting λ = 5.5 μm as the lognormal median (which is consistent with the stated number-weighted mean of 10.4 μm for σ = 1.1), the D³-weighted (volume) fraction of grains above 100 μm is about 75%, not the stated 36%, and the volume-weighted mean size is about 380 μm; moreover, about 64% of the volume would lie above the largest observed size of 140 μm. Either the fitting parameters, the '36%' figure, the weighting convention (number vs area vs volume), or the truncation of the distribution at 140 μm needs to be clarified. This matters directly, because the claim that a 0.4% count fraction of grains controls 36% of the volume is one of the two quantitative pillars of the grain-size attribution. Please report the number of SEM-counted grains, the uncertainties in the fitted parameters, the explicit functional form of the lognormal (the typeset equation is garbled in the text), and how the large-grain volume fraction was computed.","section":"Sec. 3 and Fig. 2b, grain-size statistics"},{"comment":"The 'pinning mechanism is essentially the same' conclusion is the second pillar of the attribution but is itself based on thin data. The Dew-Hughes fit uses only one temperature (80 K, the only temperature at which Hirr was reached within the field range), and the discrimination among the four models in Fig. 6 is shown without error bars; over 4.2–80 K the exponential (weak collective) and power-law (δTc, δl) models are often hard to distinguish. More importantly, the quantitative comparison 'comparable values of jc' that supports 'pinning unchanged' inherits the factor-of-order-30 uncertainty in D from the first major comment. Please add uncertainty bands to jc(T) and Fp(H) propagated from D and from the ΔM measurement, and state explicitly which conclusions are shape-based (D-independent) and which are magnitude-based (D-dependent). The shape-based pinning mechanism statement may survive unchanged, but the magnitude-based comparisons need to be re-examined.","section":"Sec. 4, Figs. 5 and 6, pinning evidence"}],"minor_comments":[{"comment":"The text cites '(Fig. 3b)' twice when referring to Mmax and Mrem; both quantities are marked on the hysteresis loop in Fig. 4, not in Fig. 3, so the figure references should be corrected.","section":"Sec. 4, text references to figures"},{"comment":"The name 'Dew-Hughes' is misspelled as 'Dew-Huge' in two places; the scaling law should be attributed to Dew-Hughes.","section":"Sec. 4 and Fig. 5 caption"},{"comment":"The typeset lognormal distribution equation is corrupted and unreadable in the manuscript; please restore the explicit formula so that the parameters λ and σ can be interpreted unambiguously.","section":"Sec. 4, lognormal equation"},{"comment":"The sentence containing 'We assume that these largest grains and have NdBa2Cu3O7-d cores' should be corrected grammatically, and the assumption itself would be substantiated by energy-dispersive X-ray (EDX) mapping across a large grain, which would strengthen the proposed seeding mechanism.","section":"Sec. 4, core-shell assumption"},{"comment":"The phrase 'record values of ΔM among polycrystalline high-Tc superconductors' is not supported by a systematic comparison with a defined literature set; please either provide a quantitative benchmark or soften the wording.","section":"Conclusion"},{"comment":"The conversion from magnetization (emu/g) to critical current density (A/cm²) implicitly requires a sample mass density; please state the density used in the conversion.","section":"Sec. 4, jc conversion"},{"comment":"The cooling rate is given as '0.5° per minute'; please specify the unit as °C/min and state whether the cooling was controlled through the peritectic range or over the full anneal.","section":"Sec. 2, cooling rate"}],"recommendation":"major_revision","confidential_remarks":"The load-bearing current-loop formula (Ref. [33]) and the jc-estimation framework (Ref. [15]) come from the authors' own prior work; self-citation is not objectionable per se, but the central attribution would be materially strengthened by a validation that does not rest only on the same group's model. Given the prominent 'record ΔM' claim, the editors may wish to have the claim checked against a clearly defined literature comparator set. The paper is otherwise a compact, readable experimental study that fits a specialized superconductivity journal; the main revision should focus on the current-loop scale determination and the internal consistency of the grain-size statistics."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The novel part is real: mixing 20 vol% refractory Nd123 with Tm123 and annealing between their peritectic temperatures gives a RE-123 ceramic with a long tail of grains up to ~0.1 mm, and the magnetization width ΔM is several times larger than in typical solid-state REBCO. The SEM grain-size distribution, XRD phase analysis, and magnetization loops are all direct measurements; the lognormal fit is fine. The pinning analysis (Dew-Hughes scaling, jc(T) fits) is competently done. So there is a solid experimental core here.\n\nThe soft spot is the bridge between ΔM and grain size. The authors estimate the current-loop scale D from the loop-asymmetry formula of their own prior work: D ≈ 2λ/[1−(ΔM/2|Mmax|)^{1/3}], getting 11 μm, and then equate that with the number-weighted average grain size from SEM (10.4 μm). But the measured ΔM is a volume-weighted sum over grains, and the lognormal distribution they report has 36% of the volume in grains larger than 0.1 mm. For such a distribution, the volume-weighted effective loop scale is something like 100–400 μm, not 11 μm. That means one of two things: either the large grains carry current over their full size and jc is actually much lower than the reported 7.2×10^6 A/cm² (so the 'pinning unchanged' conclusion collapses), or the large grains do not contribute coherently to the hysteresis, in which case they cannot be the cause of the high ΔM. The paper gives no evidence to distinguish these cases. The single D value has no error bars or field dependence, despite the formula being extremely sensitive near ΔM/2|Mmax| ≈ 1.\n\nAlso worth noting: the comparison sample Y0.75Nd0.25BCO is not composition-matched, the 'record values' phrasing is stronger than the data warrant, and the fitted pinning parameters have no uncertainties. These are all addressable. The stress-test note you sent lands: the attribution to grain size is not established, though the synthesis result is.\n\nWho is this for? Someone working on grain growth in RE-123 ceramics will find the method worth trying. But the causal story needs a proper matched control and a careful treatment of the current-loop scale, ideally by measuring D field-dependently or by direct magneto-optical imaging. I would send it to review rather than desk-reject, because the synthesis route is new and the flaws are fixable. My vote: major revision, with the interpretation toned down until the loop-scale question is resolved.","headline":"The synthesis route is genuinely new and the grain growth is real, but the paper's central claim that larger grains cause the high ΔM rests on a model-dependent current-loop scale that is probably too small by an order of magnitude.","tokens_in":10780,"tokens_out":1779,"would_cite":true,"duration_ms":21123,"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":"Bigger grains, not pinning, drive a superconductor's record hysteresis.","keywords":["high-temperature superconductors","REBCO","solid-state synthesis","top-seeded melt growth","grain size","magnetization hysteresis","critical current density","flux pinning"],"falsifier":"Crush a Tm123(Nd123) pellet to a powder with grain sizes near 5 µm without re-annealing and remeasure the magnetization loop at 4.2 K and 80 K: the paper's claim predicts that $\\Delta M$ falls to conventional polycrystalline values while the normalized pinning-force curve $F_p(H)/F_{p,\\max}$ stays the same. A complementary check is magneto-optical imaging of the polished surface to see whether shielding currents encircle the 0.1-mm grains or only roughly 11-µm regions.","tokens_in":9647,"feed_emoji":"🧲","tokens_out":7023,"duration_ms":65417,"temperature":0.7,"pith_summary":"The paper claims that the large magnetization hysteresis $\\Delta M$ of a polycrystalline REBCO superconductor comes from unusually large grains, not from better flux pinning. The authors mix a refractory NdBa$_2$Cu$_3$O$_7$ ceramic with a lower-melting TmBa$_2$Cu$_3$O$_7$ ceramic and anneal at the latter's peritectic temperature, so the Tm-based phase melts and regrows around Nd-based seed grains. The result is a long tail of grains up to 0.1 mm: only 0.4% of the grain count, but 36% of the volume. Temperature-dependent critical-current and pinning-force data match standard solid-state REBCO, so the authors attribute the several-fold increase in $\\Delta M$ and the 0.167 T trapped field to the larger current-circulation scale.","feed_headline":"Bigger grains, not pinning, drive a superconductor's record hysteresis","feed_subtitle":"A seed-assisted solid-state anneal grows 0.1-mm grains that lift ΔM several-fold with unchanged flux pinning.","key_machinery":"The load-bearing device is the peritectic-temperature contrast between two 1-2-3 compounds used as a seed-growth step: refractory NdBa$_2$Cu$_3$O$_{7-\\delta}$ (peritectic 1068 °C) stays solid while TmBa$_2$Cu$_3$O$_{7-\\delta}$ (peritectic 980 °C) forms a liquid that regrows around the Nd grains on slow cooling. A second element is the extraction of the current-circulation scale from loop asymmetry, $D \\approx 2\\lambda/[1-(\\Delta M/2|M_{\\max}|)^{1/3}]$ with $\\lambda = 150$ nm, which turns the measured magnetization width into the intragrain critical current density $j_c = 3\\Delta M/D$ and ties $\\Delta M$ to grain size. The lognormal grain-size distribution from SEM (parameters A=120, σ=1.1, λ=5.5 µm) supplies the geometric counterpart: an average size of 10.4 µm, with the largest grains (up to 140 µm) carrying 36% of the volume.","core_discovery":"On the authors' account, annealing a 20:80 vol% mixture of NdBa$_2$Cu$_3$O$_{7-\\delta}$ (peritectic 1068 °C) and TmBa$_2$Cu$_3$O$_{7-\\delta}$ (peritectic 980 °C) at 980 °C for one hour creates a liquid phase from the Tm compound, which then grows around the still-solid Nd compound as seed crystals during slow cooling. The product Tm123(Nd123) has an average grain size of 10.4 µm with a 0.4% tail of grains exceeding 0.1 mm, and its magnetization width $\\Delta M$ is several times larger than in conventional polycrystalline REBCO and in the precursor ceramics. From the asymmetry of the hysteresis loop the authors extract a current-circulation scale $D \\approx 11\\,\\mu$m, matching the SEM average grain size, and compute intragrain critical current densities $j_c = 3\\Delta M/D$ up to about $7\\times10^6$ A/cm$^2$ at 4.2 K (about $1\\times10^7$ A/cm$^2$ after correcting for the 69% superconducting-phase content). Because $j_c(T)$ follows weak collective pinning and the pinning-force curve follows the same standard scaling as polycrystalline REBCO, the paper concludes that pinning is essentially unchanged and that the large grains are the main reason for the high $\\Delta M$ and for the trapped field $B_{\\mathrm{tr}} = 0.167$ T.","pith_inferences":["Editorial inference: the same two-precursor seed strategy should transfer to other RE-123 pairs with well-separated peritectic temperatures, for example Yb/Er or Y/Nd, and could be optimized by varying the seed volume fraction and cooling rate.","Editorial inference: the claim would be tested directly by crushing the Tm123(Nd123) pellet back to roughly 5 µm powder and re-measuring the hysteresis loop; the grain-size hypothesis predicts that $\\Delta M$ collapses to conventional values while the pinning scaling stays the same.","Editorial inference: if the loop-asymmetry formula underestimates the true current loop in a two-phase ceramic with 0.1-mm grains, the inferred intragrain $j_c$ would shift upward and the 'pinning unchanged' conclusion would need revisiting; magneto-optical imaging of the shielding currents across individual grains could settle this."],"forward_implications":["Grain-size engineering alone can raise the magnetization width and trapped field of polycrystalline REBCO several-fold without altering the vortex-pinning mechanism.","Comparisons of $\\Delta M$ between ceramic superconductors should account for grain size before invoking new pinning centres.","Because annealing time controls the tail of the grain-size distribution, tuning time, temperature, and precursor concentrations should push the large-grain volume fraction higher and reduce the 30 wt% secondary phases.","Ceramic 1-2-3 samples made this way can trap about 0.167 T at 4.2 K, above the roughly 0.1 T typical of conventional solid-state REBCO, which is relevant for trapped-field applications.","The intragrain critical current density of the large-grain ceramic matches standard polycrystalline REBCO, implying that the high $\\Delta M$ is not evidence of stronger flux pinning."],"supporting_citations":[{"why":"Supplies the loop-asymmetry formula used to extract the current-circulation scale D from the magnetization loop.","marker":"[33]"},{"why":"Justifies treating the magnetization-hysteresis estimate as the intragrain critical current density in polycrystalline superconductors.","marker":"[15]"},{"why":"Provides the comparison Y$_{0.75}$Nd$_{0.25}$Ba$_2$Cu$_3$O$_{7-\\delta}$ sample with 3.8 µm grains and a smaller $\\Delta M$.","marker":"[18]"},{"why":"Reports the precursor Tm123 and Nd123 ceramics with smaller $\\Delta M$, serving as the baseline the new material must beat.","marker":"[31]"},{"why":"Supplies the alternative hypothesis that configurational entropy raises the critical current density, which the pinning analysis tests against.","marker":"[32]"},{"why":"Provides the earlier interface-growth method that the new seed-assisted synthesis extends.","marker":"[24]"},{"why":"Documents seeded infiltration and melt growth for large single-domain REBCO, the technique the authors adapt to a solid-state route.","marker":"[25]"},{"why":"Gives the standard solid-state Y(Gd)BCO pinning behavior used to show that the present material's pinning is unchanged.","marker":"[14]"}],"fun_headline_variants":["Seed-assisted growth enlarges grains, boosting superconductor hysteresis","Bigger grains, same pinning: why ΔM jumps in REBCO ceramics","Grain size, not pinning, explains enhanced magnetization in Tm-Nd cuprate","0.1-mm grains lift ΔM without changing flux pinning mechanism","Seeded solid-state route yields larger grains, stronger ΔM"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The whole grain-size attribution rests on the loop-asymmetry estimate $D \\approx 11\\,\\mu$m being the true scale of circulating currents; if the formula misreads the two-phase microstructure with its 30 wt% secondary phases, the inferred intragrain current density shifts and the conclusion that pinning is unchanged could fail.","fun_headline_variants_meta":{"raw":{"variants":["Seed-assisted growth enlarges grains, boosting superconductor hysteresis","Bigger grains, same pinning: why ΔM jumps in REBCO ceramics","Grain size, not pinning, explains enhanced magnetization in Tm-Nd cuprate","0.1-mm grains lift ΔM without changing flux pinning mechanism","Seeded solid-state route yields larger grains, stronger ΔM"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000897,"raw_usage":{"total_tokens":3926,"prompt_tokens":1069,"completion_tokens":2857,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":685,"completion_tokens_details":{"reasoning_tokens":2758}},"tokens_in":685,"tokens_out":2857,"duration_ms":20279,"temperature":1.0,"reasoning_tokens":2758,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-11T18:13:22.079482+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Crush a Tm123(Nd123) pellet to a powder with grain sizes near 5 µm without re-annealing and remeasure the magnetization loop at 4.2 K and 80 K: the paper's claim predicts that $\\Delta M$ falls to conventional polycrystalline values while the normalized pinning-force curve $F_p(H)/F_{p,\\max}$ stays the same. A complementary check is magneto-optical imaging of the polished surface to see whether shielding currents encircle the 0.1-mm grains or only roughly 11-µm regions.","supporting_citations":[{"cited_title":"Gokhfeld, The circulation radius and critical current density in type II superconductors, Tech","cited_arxiv_id":null,"evidence_quote":"Supplies the loop-asymmetry formula used to extract the current-circulation scale D from the magnetization loop."},{"cited_title":"Gokhfeld, On Estimating the Critical Current Density in Polycrystalline Superconductors Synthesized by Solid-State Method, J","cited_arxiv_id":null,"evidence_quote":"Justifies treating the magnetization-hysteresis estimate as the intragrain critical current density in polycrystalline superconductors."},{"cited_title":"Gokhfeld, D.A","cited_arxiv_id":null,"evidence_quote":"Provides the comparison Y$_{0.75}$Nd$_{0.25}$Ba$_2$Cu$_3$O$_{7-\\delta}$ sample with 3.8 µm grains and a smaller $\\Delta M$."},{"cited_title":"Petrov, D.M","cited_arxiv_id":null,"evidence_quote":"Reports the precursor Tm123 and Nd123 ceramics with smaller $\\Delta M$, serving as the baseline the new material must beat."},{"cited_title":"Yamashita, Y","cited_arxiv_id":null,"evidence_quote":"Supplies the alternative hypothesis that configurational entropy raises the critical current density, which the pinning analysis tests against."},{"cited_title":"Petrov, S.I","cited_arxiv_id":null,"evidence_quote":"Provides the earlier interface-growth method that the new seed-assisted synthesis extends."},{"cited_title":"Iida, N.H","cited_arxiv_id":null,"evidence_quote":"Documents seeded infiltration and melt growth for large single-domain REBCO, the technique the authors adapt to a solid-state route."}],"review_version":1}