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REVIEW 3 major objections 6 minor 16 references

Growth of (111)-textured SrTiO3 thin films on Pt(111)/Al2O3(1-102) substrates by rf magnetron sputter deposition

T0 review · 3 major / 6 minor · reviewed 2026-07-09 · glm-5.2

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Pith's one-line read Smooth SrTiO3 Films Grown on Platinum Templates

desk verdict Smooth (111)-textured STO on Pt/sapphire by RF sputtering, but the key crystalline-quality metric is confounded by Pt/STO peak overlap read the letter →

arxiv 2607.07428 v1 pith:UJ5J47U6 submitted 2026-07-08 cond-mat.mtrl-sci

Ekaterina Taylor , Ethan R. Cronk , Kalani Perera , Nuri W. Emanetoglu , Nicholas S. Bingham This is my paper · ORCID
classification cond-mat.mtrl-sci
keywords SrTiO3thinfilmsputteringPttemplate(111)texturerockingcurveRHEEDgrowth
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper demonstrates that SrTiO3 (STO) thin films, 20–30 nm thick, can be grown with strong (111) crystal orientation and atomically smooth surfaces (RMS roughness ~110 pm) on Pt(111)/Al2O3 substrates using RF magnetron sputtering. The central claim is that the crystalline quality and surface smoothness of the STO film are directly inherited from the underlying Pt template, which is itself controlled by the Pt sputtering power. Lower Pt sputtering power (90 W vs. 180 W) yields Pt films with superior crystal quality (rocking curve FWHM ~0.2°) and smoother surfaces, and STO grown on these templates adopts that same orientation and smoothness. XPS confirms stoichiometric composition; XRD shows (111)/(222) texture; RHEED shows streaky patterns consistent with quasi-2D growth. The paper argues that by optimizing the Pt layer, one can produce near-epitaxial STO films thin enough and smooth enough to serve as dielectric layers in capacitors or as templates for complex oxide growth.

What carries the argument

The mechanism is template-inherited growth: Pt(111) and STO(111) have nearly identical lattice constants (3.92 Å vs. 3.905 Å), so STO adopts the Pt crystallographic orientation. Pt sputtering power controls Pt grain quality and surface roughness; STO deposited on that template replicates both.

What would settle it

If high-resolution XRD or pole-figure analysis resolving the STO(111) peak independently showed a much broader rocking curve than 0.2°, the claim of high STO crystalline quality would be undermined.

Watch

Extended reading notes

Core claim

The paper identifies the underlying Pt template quality, governed by sputtering power during Pt deposition, as the determining factor for STO thin film quality. STO films grown on high-quality Pt (deposited at 90 W, 600°C) exhibit (111) orientation, a rocking curve FWHM of 0.2°, and RMS surface roughness of ~110 pm, closely matching the Pt template roughness of ~93 pm. The STO film's morphology and crystallographic orientation follow the Pt template rather than being independently controlled by STO growth parameters alone.

Load-bearing premise

The paper attributes the 0.2° rocking curve FWHM to the STO film, but because Pt(111) and STO(111) diffraction peaks overlap almost exactly and no distinct STO peak is resolved, the measured FWHM could be dominated by the Pt reflection rather than the STO film itself.

Editorial extensions

If this is right

  • STO films thin enough (20–30 nm) and smooth enough (<1 nm RMS) for sub-50 nm capacitor dielectrics become accessible via a sputter-based route, avoiding the need for single-crystal STO substrates.
  • The template-inheritance principle suggests that other lattice-matched oxide/electrode pairs could be engineered similarly by optimizing the electrode layer first.
  • If the Pt–STO lattice match is sufficient for near-epitaxial quality, these films could serve as low-cost templates for growing complex oxides that normally require expensive single-crystal STO substrates.
  • The projected capacitance density of 8.85–13.28 μF/cm² would need direct electrical measurement to confirm that the structural quality translates to dielectric performance.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The overlapping Pt(111) and STO(111) diffraction peaks (2θ = 39.763° vs. 39.984°) mean the 0.2° rocking curve FWHM may reflect Pt quality rather than STO quality alone; the STO contribution is inferred from a shoulder on the rocking curve, not from an independently resolved peak. Pole-figure or high-resolution XRD would be needed to confirm STO crystalline quality separately.
  • The RHEED streaks and AFM smoothness provide independent evidence of STO surface quality, but the in-plane crystallographic relationship between STO and Pt (e.g., rotational domains, twin structure) is not directly characterized by the presented data.
  • The absence of measured dielectric properties means the link between structural quality and capacitor performance remains projected rather than demonstrated.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. This manuscript reports the growth of (111)-textured SrTiO3 (STO) thin films (20–60 nm) on Pt(111)/r-Al2O3 substrates by RF magnetron sputtering. The authors vary Pt sputtering power (90 W vs. 180 W) and STO growth parameters, and characterize the resulting films using XRD, XPS, AFM, and RHEED. They report that lower Pt sputtering power yields smoother, better-crystallized Pt templates, which in turn promote highly textured STO growth with atomically smooth surfaces (RMS ~110 pm). The central claims are: (i) stoichiometric, (111)-oriented STO films are achieved, (ii) the STO films exhibit a rocking curve FWHM of 0.2°, indicating high crystalline quality, and (iii) Pt template quality directly determines STO film quality.

Significance. The growth of thin, smooth, (111)-textured STO on Pt/sapphire is of practical interest for capacitor dielectrics and as a template for complex oxide heterostructures. The AFM data showing ~110 pm RMS roughness and the RHEED streaky pattern are credible evidence of smooth, well-ordered surfaces. The systematic comparison of Pt growth conditions and their effect on STO quality is a useful contribution. However, the significance is substantially undermined by the unresolved attribution of the key crystalline-quality metric (see Major Comments).

major comments (3)
  1. §'Film orientation and crystal structure quality' and §'Conclusions': The 0.2° rocking curve FWHM is explicitly attributed to the Pt(111) reflection in the Results ('The FWHM of the Pt(111) reflection decreases from 3.0° ... to 0.2° for the film deposited at 90 W'), yet the Conclusion reassigns this value to STO ('XRD rocking curve measurements of the STO films have a narrow full width at half maximum of 0.2°'). The paper itself states that Pt(111) (2θ = 39.763°) and STO(111) (2θ = 39.984°) are unresolved and that 'no distinct STO peak is observed separately from the Pt peak.' Furthermore, the authors note a shoulder in the RC of the higher-quality film 'which indicates the presence of STO with wider RC FWHM' — i.e., the authors' own observation suggests STO has a broader (worse) FWHM than the 0.2° Pt value. This is a load-bearing conflation: the central crystalline-quality claim for STO
  2. §'Conclusions': Capacitance values (8.85–13.28 μF/cm²) are cited with no electrical measurements (C-V, I-V, or impedance spectroscopy) presented anywhere in the manuscript. These values appear to be calculated from the parallel-plate formula using the STO dielectric constant and film thickness, but this is not stated. Including predicted or calculated capacitance without clearly labeling it as such, and without any experimental validation, is an unsupported claim that should be removed or explicitly reframed as a projection.
  3. §'Composition Analysis', Table 2: The paper claims 'stoichiometric STO thin films,' but the XPS concentrations reported are Sr 25.7%, Ti 23.7%, O 50.6% (atomic), corresponding to Sr:Ti:O ≈ 1.08:1:2.13 rather than 1:1:3. While XPS surface composition can deviate from bulk stoichiometry, the claim of stoichiometry needs to be reconciled with these numbers or qualified. The ±10% error bars do not fully account for the O deficiency relative to the expected 60% for stoichiometric STO.
minor comments (6)
  1. Figure 3 caption states '0.27° FWHM' for the 90 W sample, while the text and conclusion state 0.2°. Please reconcile.
  2. Figure numbering appears inconsistent: the RHEED image is labeled 'Figure 5' in the caption but referenced as 'Fig. 6' in the text.
  3. Table 1 is difficult to parse — it is unclear which rows correspond to which target-substrate distance and power combinations, and the column headers are not clearly labeled in the text flow.
  4. The abstract states 'stoichiometric STO thin films' — given the XPS results in Table 2, this should be softened or qualified.
  5. §'Experimental Details': The STO growth temperature (300°C) and annealing temperature (550°C) are mentioned, but it would help to clarify whether the Pt was grown at 600°C in the same chamber or a different system (the text mentions 'two different sputtering systems').
  6. Reference 13 (Paik et al., 2025) is cited in the Introduction regarding the need for high-resolution XRD or pole-figure analysis to distinguish STO from Pt — the authors should explicitly acknowledge that their own data face this exact limitation and discuss what additional measurements would resolve it.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for a careful reading of the manuscript and for identifying three substantive issues. All three major comments are well-taken. The conflation of the Pt rocking curve FWHM with the STO FWHM is a genuine error in our Conclusions section that we will correct. The capacitance values are indeed calculated projections rather than measured values and will be explicitly labeled as such. The XPS stoichiometry claim requires qualification given the reported atomic percentages. We provide point-by-point responses below.

read point-by-point responses

  1. Referee: The 0.2° rocking curve FWHM is explicitly attributed to the Pt(111) reflection in the Results, yet the Conclusion reassigns this value to STO. The paper itself states that Pt(111) and STO(111) are unresolved and that no distinct STO peak is observed separately from the Pt peak. Furthermore, the authors note a shoulder in the RC of the higher-quality film which indicates the presence of STO with wider RC FWHM. This is a load-bearing conflation of the central crystalline-quality claim for STO.

    Authors: The referee is correct, and we acknowledge this as a genuine error in our manuscript. The 0.2° FWHM reported in the Results section refers specifically to the Pt(111) reflection of the Pt template grown at 90 W. In the Conclusions section, we incorrectly attributed this value to the STO films. As the referee notes, our own manuscript states that the Pt(111) and STO(111) peaks are unresolved (2θ = 39.763° and 39.984°, respectively), and we explicitly observe a shoulder in the rocking curve of the higher-quality film, which we interpret as STO with a broader FWHM than the Pt peak. We will revise the Conclusions and Abstract to accurately state that the 0.2° FWHM corresponds to the Pt(111) template, and that the STO film's rocking curve FWHM cannot be independently resolved from the Pt peak but is inferred to be broader based on the observed shoulder. We will also add a discussion of the limitations imposed by the peak overlap on our ability to independently quantify STO crystalline quality. We agree that the central crystalline-quality claim for STO was overstated and will be corrected accordingly. revision: yes

  2. Referee: Capacitance values (8.85–13.28 μF/cm²) are cited with no electrical measurements (C-V, I-V, or impedance spectroscopy) presented anywhere in the manuscript. These values appear to be calculated from the parallel-plate formula using the STO dielectric constant and film thickness, but this is not stated. Including predicted or calculated capacitance without clearly labeling it as such, and without any experimental validation, is an unsupported claim that should be removed or explicitly reframed as a projection.

    Authors: The referee is correct. The capacitance values cited in the Conclusions are calculated projections based on the parallel-plate capacitor formula C = ε₀εᵣ/d, using the bulk STO dielectric constant (εᵣ ≈ 300) and the range of film thicknesses (20–30 nm), not experimentally measured values. No C-V, I-V, or impedance spectroscopy measurements were performed. We agree that presenting these values without clearly labeling them as projections is misleading. We will revise the Conclusions to explicitly state that these are projected capacitance values calculated from bulk dielectric properties and measured film thicknesses, and we will note that experimental electrical characterization is needed to validate these projections. Alternatively, if the referee prefers, we can remove the capacitance values entirely from the Conclusions. revision: yes

  3. Referee: The paper claims 'stoichiometric STO thin films,' but the XPS concentrations reported are Sr 25.7%, Ti 23.7%, O 50.6% (atomic), corresponding to Sr:Ti:O ≈ 1.08:1:2.13 rather than 1:1:3. While XPS surface composition can deviate from bulk stoichiometry, the claim of stoichiometry needs to be reconciled with these numbers or qualified. The ±10% error bars do not fully account for the O deficiency relative to the expected 60% for stoichiometric STO.

    Authors: The referee raises a valid point. The XPS atomic concentrations we report (Sr 25.7%, Ti 23.7%, O 50.6%) correspond to Sr:Ti:O ≈ 1.08:1:2.13, which deviates from the ideal 1:1:3 stoichiometry, particularly in the oxygen content. We agree that the ±10% error bars do not fully account for the oxygen deficiency relative to the expected 60 at.% for stoichiometric STO. XPS is a surface-sensitive technique and the measured composition can be affected by surface contamination, preferential sputtering, and the presence of adventitious carbon (the C 1s signal is present in our survey spectrum). Additionally, the O 1s peak likely contains contributions from surface hydroxyl and carbonate species that may not be fully deconvoluted from the lattice oxygen signal. However, we acknowledge that the claim of 'stoichiometric STO thin films' is not adequately supported by the XPS data as presented. We will qualify this claim in the revised manuscript, noting that the Sr:Ti ratio is near unity within experimental error (1.08:1), while the oxygen content is below the nominal stoichiometric value, and we will discuss possible reasons for this deviation including surface effects and peak fitting limitations. We will also note that bulk stoichiometry may differ from the XPS-derived surface composition and that complementary techniques such as Rutherford backscattering spectrometry would be needed to verify bulk stoichiometry. revision: yes

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity: growth parameters are set independently and characterization measures outcomes directly

full rationale

This is an experimental materials science paper with no formal derivation chain. Growth parameters (sputtering power, temperature, pressure, distance, time) are set independently as experimental inputs, and characterization methods (XRD, AFM, XPS, RHEED) measure the resulting film properties as outputs. There is no self-definitional loop, no fitted parameter renamed as prediction, no self-citation chain that is load-bearing for a central claim, and no ansatz smuggled in via citation. The paper's self-citations are minimal: reference 16 is a third-party RHEED analysis toolkit, and reference 13 is a third-party paper by Paik et al. The central claim that Pt quality determines STO quality is supported by comparing two Pt conditions (90W vs 180W) with different measured outcomes. The reader's concern about the 0.2° rocking curve FWHM being attributed to STO when it is measured at the unresolved Pt(111)/STO(111) overlap is a correctness/conflation issue, not circularity: the measurement is not defined in terms of the prediction, nor is a fitted parameter presented as a first-principles result. The unsupported capacitance values in the conclusion are an overclaim but again not circular. No step in the paper reduces to its own inputs by construction.

Assumptions & free parameters 6 free parameters · 3 assumptions · 0 invented entities

The paper introduces no new entities, particles, or theoretical constructs. It is a purely experimental thin-film growth study. The free parameters are all process conditions chosen empirically without systematic optimization. The key ad hoc axiom is the attribution of the rocking curve FWHM to STO despite unresolved Pt/STO peaks.

free parameters (6)
  • Pt sputtering power = 90 W or 180 W
    Two power levels chosen empirically; 90 W found to produce better Pt quality.
  • STO sputtering power = 20 W, 30 W, or 40 W
    Three power levels tested; no systematic optimization shown.
  • STO growth temperature = 300°C
    Fixed temperature chosen without justification against alternatives.
  • STO annealing conditions = 550°C, 1 hour, 300+ mTorr O2
    Post-growth anneal parameters chosen empirically.
  • Ar/O2 pressure ratio = 3 mTorr Ar / 7 mTorr O2
    Gas mixture chosen without systematic variation or justification.
  • Target-substrate distance = 12 cm or 14 cm
    Two distances used; rationale for selection not discussed.
assumptions (3)
  • domain assumption Pt(111) and STO(111) have sufficiently close lattice constants (3.92 Å vs. 3.905 Å) to enable textured growth.
    Stated in Introduction; standard materials science knowledge.
  • domain assumption XPS surface concentrations reflect bulk film stoichiometry.
    XPS is surface-sensitive (~5-10 nm depth); the paper uses it to verify stoichiometry of 20-60 nm films without depth profiling.
  • ad hoc to paper The 0.2° rocking curve FWHM reflects STO film quality rather than the Pt underlayer.
    The paper attributes the FWHM to STO but the Pt and STO peaks are unresolved in the XRD data, making this attribution unverified.

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Cite this review

Pith. "Pith review of Growth of (111)-textured SrTiO3 thin films on Pt(111)/Al2O3(1-102) substrates by rf magnetron sputter deposition." pith.science (2026). https://pith.science/paper/UJ5J47U6

@misc{pith2026260707428,
  author       = {Pith},
  title        = {Pith review of: Growth of (111)-textured SrTiO3 thin films on Pt(111)/Al2O3(1-102) substrates by rf magnetron sputter deposition},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/UJ5J47U6}},
  note         = {Machine review of arXiv:2607.07428}
}
read the original abstract

SrTiO3 thin films, 20-30nm, with high quality crystal structure and low roughness can be used as growth templates for complex oxides or as the dielectric materials for capacitor structures. In this work, stoichiometric STO thin films were grown by radio frequency magnetron sputtering on Pt (111) templates grown on rAl2O3 substrates, and the effects of growth parameters as well as the underlying Pt templates structural properties on the quality of STO films were studied. A comparison between room temp grown Pt and Pt grown at elevated temps showed that the latter lead to highly ordered Pt and STO films with quasi 2D surface roughness. Xray diffraction showed that the STO thin films had (111) and (222) crystal orientation. A rocking curve full width at half maximum value of 0.2{\deg} was achieved, indicating that the STO films are high-quality. The STO films have a roughness less than 1 nm, as measured using atomic force microscopy, comparable to the underlying Pt templates roughness.

Figures

Figures reproduced from arXiv: 2607.07428 by the authors.

Figure 4
Figure 4. Atomic force microscopy of, (a) Pt 180 W growth, (b) Pt 90 W growth, (c) 30nm-thick SrTiO3 on Pt/(𝟏𝟏ഥ𝟎𝟐) Al2O3 [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 5
Figure 5. Reflection high-energy electron diffraction of STO/Pt/Al2O3 multilayer [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗

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Works this paper leans on

16 extracted references · 16 canonical work pages

  1. [1]

    Dielectric properties of (Ba,Sr )TiO3 thin films in MHz and THz frequency regions: Quantitative evaluation of the orientational polarization

    Kawayama, Iwao & Kotani, Kenta & Misra, Mahesh & Murakami, Hironaru & Tonouchi, Masayoshi. Dielectric properties of (Ba,Sr )TiO3 thin films in MHz and THz frequency regions: Quantitative evaluation of the orientational polarization. Japanese Journal of Applied Physics. 53. 09PD06. 10.7567/JJAP.53.09PD06

    work page doi:10.7567/jjap.53.09pd06

  2. [2]

    Highly insulated STO thin films: International Conference on Ion Implantation,

    K. Akedo, H. Fujisaka, M. Suzuki, and Y. Taga, “Highly insulated STO thin films: International Conference on Ion Implantation,” IEEE, Piscataway, NJ, USA 2, 970 – 973(1998)

    work page 1998

  3. [3]

    Thomas, Reji & Bhakta, Raghunandan & Ehrhart, Peter & Fischer, Roland & Waser, Rainer & Devi, Anjana. (2007). Liquid injection MOCVD of TiO2 and SrTiO3 thin films from [Ti(OPri)2(tbaoac)2]: Film properties and compatibility with [Sr(thd)2]. Surface and Coatings Technology. 201. 9135-9140. 10.1016/j.surfcoat.2007.04.038

    work page doi:10.1016/j.surfcoat.2007.04.038 2007

  4. [4]

    Preparation and characterization of RF-sputtered STO thin films,

    K. Radhakrishnan, C. L. Tan, H. Q. Zheng, and G. I. Ng, “Preparation and characterization of RF-sputtered STO thin films,” J. vac. Sci. Technol. A 18(4), 1638–1641 (2000)

    work page 2000

  5. [5]

    Electrical properties of STO thin films by multi-ion beam reactive sputtering technique,

    C.-J. Peng, H. Hu, and S. B. Krupanidhi, “Electrical properties of STO thin films by multi-ion beam reactive sputtering technique,” Appl. Phys. Lett. 63(8), 1039–1040 (1993)

    work page 1993

  6. [6]

    Fabrication of a high-Tc super- conducting field effect transistor by ion beam sputtering,

    T. Saito, X. Cai, K. Usami, T. Kobayashi, and T. Goto, “Fabrication of a high-Tc super- conducting field effect transistor by ion beam sputtering,” IEEE transactions on Applied Superconductivity 7(2), 3528–3531 (1997)

    work page 1997

  7. [7]

    Gasidit Panomsuwan, Osamu Takai, Nagahiro Saito, Growth of highly (110)- and (111)- textured SrTiO3 thin films on Pt(111)/α-Al2O3(0001) substrates by ECR ion beam sputter deposition, Solid State Communications, Volume 158,2013,Pages 65-69,ISSN 0038-1098, https://doi.org/10.1016/j.ssc.2012.12.026

    work page doi:10.1016/j.ssc.2012.12.026 2013

  8. [8]

    Structure and dielectric properties of STO films prepared by pulsed laser deposition technique,

    M. H. Yeh, K. -S. Liu, and I. -N Lin, “Structure and dielectric properties of STO films prepared by pulsed laser deposition technique,” Jpn. J. Appl. Phys. 34, 2447–2452 (1995)

    work page 1995

Show all 16 references
  1. [9]

    Atomic Layer Deposition of Multicomponent Oxide Materials

    Marko Vehkamäki, “Atomic Layer Deposition of Multicomponent Oxide Materials”, Laboratory of Inorganic Chemistry, University of Helsinki (2007)

    2007

  2. [10]

    Woo, S., Jeong, H., Lee, S. et al. Surface properties of atomically flat poly -crystalline SrTiO3. Sci Rep 5, 8822 (2015).https://doi.org/10.1038/srep088

    2015 doi

  3. [11]

    Keane, Susanne Stemmer; Contributions to the dielectric losses of textured thin films with Pt electrodes

    Jiwei Lu, Steffen Schmidt, Young -Woo Ok, Sean P. Keane, Susanne Stemmer; Contributions to the dielectric losses of textured thin films with Pt electrodes. J. Appl. Phys. 1 September 2005; 98 (5): 054101

    2005

  4. [12]

    Electrical and structural properties of STO thin films deposited by plasma -enhanced metalorganic chemical vapour deposition,

    N.-K. Kim and S. -G. Yoon, “Electrical and structural properties of STO thin films deposited by plasma -enhanced metalorganic chemical vapour deposition,” J. Mater. Res.12(4), 1160–1164 (1997)

    1997

  5. [13]

    K., Shin, J., Song, H., Kim, D

    Paik, H., Lim, J., Seo, H., Kim, T. K., Shin, J., Song, H., Kim, D. G., Lee, W., Kwon, D. S., & Hwang, C. S. (2025). Enhanced crystallization and dielectric properties of atomic layer deposited SrTiO3 thin films on Ru electrode by inserting GeO2 interfacia l layer. Materials H...

    2025 doi

  6. [14]

    Wang, Xiaofei & Lu, Xiaomei & Bo, Huifeng & Liu, Yaoyang & Shen, Yanchi & Wu, Xiaobo & Cai, Wei & Kan, Yi & Zhang, Chao & Liu, Yunfei & Huang, Fengzhen & Zhu, Jinsong. (2010). The structural and electrical properties of oriented SrTiO3 films prepared by metal organic depositio...

    2010 doi

  7. [15]

    SrTiO3 by XPS

    Richard P. Vasquez,“SrTiO3 by XPS” https://doi.org/10.1063/1.2034649

    doi

  8. [16]

    ORCID xRHEED: A versatile Python toolkit for RHEED image analysis

    Kopciuszynski, M. ORCID xRHEED: A versatile Python toolkit for RHEED image analysis. GitHub. https://github.com/mkopciuszynski/xrheed, DOI: 10.5281/zenodo.17099751

    doi

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