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arxiv: 1906.08710 · v1 · pith:4CRRY7RRnew · submitted 2019-06-20 · ❄️ cond-mat.supr-con

Coexistence of Eu-antiferromagnetism and pressure-induced superconductivity in EuFe2As2 single crystal

W. T. Jin , Y. Xiao , S. Nandi , S. Price , Y. Su , K. Schmalzl , W. Schmidt , T. Chatterji
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A. Thamizhavel Th. Brueckel
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Pith reviewed 2026-05-25 19:08 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con
keywords EuFe2As2neutron diffractionhigh pressuresuperconductivityantiferromagnetismiron pnictidesstructural transitionspin density wave
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The pith

Pressure induces bulk superconductivity in EuFe2As2 while preserving Eu antiferromagnetism up to 24.7 kbar.

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

High-pressure neutron diffraction on EuFe2As2 single crystals shows that both the tetragonal-to-orthorhombic structural transition and the Fe spin-density-wave transition are gradually suppressed and become decoupled as pressure rises. The antiferromagnetic order on the Eu sublattice, however, shows no change in its ordering temperature even at 24.7 kbar. At this pressure the lattice parameters exhibit clear anomalies at 27(3) K that match the superconducting transition temperature previously seen in resistivity measurements. These anomalies indicate the presence of bulk superconductivity with strong electron-lattice coupling, allowing the long-range Eu antiferromagnetic order to coexist with the superconducting state.

Core claim

Under 24.7 kbar hydrostatic pressure the Eu antiferromagnetic order remains robust with unchanged ordering temperature while lattice-parameter anomalies appear at 27(3) K, consistent with the onset of bulk superconductivity.

What carries the argument

High-pressure single-crystal neutron diffraction that tracks lattice parameters and magnetic Bragg peaks to reveal decoupling of structural and Fe-SDW transitions while confirming persistence of Eu antiferromagnetism and anomalies at the superconducting transition.

If this is right

  • Eu antiferromagnetic ordering temperature stays constant up to at least 24.7 kbar.
  • Structural and Fe spin-density-wave transitions are suppressed and decouple with increasing pressure.
  • Lattice anomalies at the superconducting transition temperature indicate strong electron-lattice coupling.
  • Long-range Eu antiferromagnetism coexists with pressure-induced superconductivity in this compound.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The robustness of Eu order may arise from its separation from the Fe layers, allowing independent tuning of the two magnetic subsystems.
  • Extending the pressure range beyond 24.7 kbar could reveal whether Eu order eventually collapses and whether a different superconducting regime appears.
  • Similar neutron experiments on doped variants could test whether the observed coexistence is tied to the specific EuFe2As2 stoichiometry.

Load-bearing premise

Lattice-parameter anomalies at 27 K under 24.7 kbar are interpreted as evidence of bulk superconductivity because they match earlier resistivity data rather than because a direct superconducting probe was performed in the neutron experiment.

What would settle it

A direct measurement such as a specific-heat jump or diamagnetic shielding under identical pressure and temperature conditions showing no superconductivity would falsify the bulk-superconductivity interpretation.

Figures

Figures reproduced from arXiv: 1906.08710 by A. Thamizhavel, K. Schmalzl, S. Nandi, S. Price, T. Chatterji, Th. Brueckel, W. Schmidt, W. T. Jin, Y. Su, Y. Xiao.

Figure 2
Figure 2. Figure 2: (Color online) (a) L-scan along the (2, 0, L) direct [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 1
Figure 1. Figure 1: (Color online) (a) Variation of peak positions of o [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 4
Figure 4. Figure 4: (Color online) Pressure-temperature phase diagr [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
read the original abstract

By performing high-pressure single-crystal neutron diffraction measurements, the evolution of structure and magnetic ordering in EuFe2As2 under hydrostatic pressure were investigated. Both the tetragonal-toorthorhombic structural transition and the Fe spin-density-wave (SDW) transition are gradually suppressed and become decoupled with increasing pressure. The antiferromagnetic order of the Eu sublattice is, however, robust against the applied pressure up to 24.7 kbar, without showing any change of the ordering temperature. Under the pressure of 24.7 kbar, the lattice parameters of EuFe2As2 display clear anomalies at 27(3) K, well consistent with the superconducting transition observed in previous high-pressure resistivity measurements. Such an anomalous thermal expansion around Tc strongly suggests the appearance of bulk superconductivity and strong electron-lattice coupling in EuFe2As2 induced by the hydrostatic pressure. The coexistence of long-range ordered Eu-antiferromagnetism and pressure-induced superconductivity is quite rare in the EuFe2As2-based iron pnictides.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 0 minor

Summary. The manuscript reports high-pressure single-crystal neutron diffraction on EuFe2As2, tracking the suppression and decoupling of the tetragonal-to-orthorhombic structural transition and Fe SDW order with increasing pressure. The Eu antiferromagnetic order remains robust up to 24.7 kbar with unchanged TN. At 24.7 kbar, clear anomalies appear in the lattice parameters at 27(3) K; these are stated to be consistent with the superconducting transition seen in prior resistivity work and are interpreted as indicating bulk superconductivity coexisting with long-range Eu AFM.

Significance. If the assignment of the 27(3) K lattice anomalies to bulk superconductivity holds, the work supplies direct microscopic confirmation of a rare coexistence between long-range Eu antiferromagnetism and pressure-induced superconductivity in the EuFe2As2 family. The neutron data on the pressure evolution of both structural and magnetic orders constitute a clear experimental strength.

major comments (1)
  1. [Abstract / 24.7 kbar results] Abstract and the 24.7 kbar data discussion: the inference that the observed lattice-parameter anomalies signal bulk superconductivity rests exclusively on temperature matching with earlier resistivity measurements rather than any in-situ transport, magnetization, or specific-heat signature collected inside the neutron experiment. This assumption is load-bearing for the coexistence claim; an alternative origin for the anomaly (structural crossover or thermal-expansion artifact) would remove the basis for concluding superconductivity is present at the same pressure and temperature as the Eu AFM order.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for highlighting an important point regarding the strength of the evidence for bulk superconductivity. We respond to the major comment below and indicate the revisions we will make.

read point-by-point responses

  1. Referee: [Abstract / 24.7 kbar results] Abstract and the 24.7 kbar data discussion: the inference that the observed lattice-parameter anomalies signal bulk superconductivity rests exclusively on temperature matching with earlier resistivity measurements rather than any in-situ transport, magnetization, or specific-heat signature collected inside the neutron experiment. This assumption is load-bearing for the coexistence claim; an alternative origin for the anomaly (structural crossover or thermal-expansion artifact) would remove the basis for concluding superconductivity is present at the same pressure and temperature as the Eu AFM order.

    Authors: We agree that the interpretation of the lattice anomalies at 27(3) K under 24.7 kbar as evidence for bulk superconductivity is indirect, relying on the temperature match with prior resistivity data and the character of the anomaly (a clear deviation from monotonic thermal contraction). Simultaneous in-situ transport or specific-heat measurements within the neutron pressure cell are not part of the present experiment and would require substantial additional instrumentation. While the observed lattice response is consistent with strong electron-lattice coupling at the superconducting transition in related compounds, we acknowledge that alternative explanations cannot be ruled out on the basis of the neutron data alone. We will therefore revise the abstract and the discussion of the 24.7 kbar results to (i) state explicitly that the assignment is an inference based on consistency with earlier transport work, (ii) note the indirect nature of the evidence, and (iii) briefly mention possible alternative origins for the anomaly. These changes constitute a partial revision that addresses the referee’s concern without altering the experimental results themselves. revision: partial

Circularity Check

0 steps flagged

No circularity: purely experimental neutron diffraction with direct observations

full rationale

The paper reports measured neutron diffraction patterns, lattice parameters, and magnetic ordering temperatures under pressure. No equations, fitted parameters, derivations, or predictions are present that could reduce to inputs by construction. The lattice anomaly at 27(3) K is directly observed and noted for consistency with external resistivity data; this is an interpretive link to prior work, not a self-referential fit or self-citation chain. All claims rest on raw diffraction data without any of the enumerated circularity patterns.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The work is experimental and relies on standard interpretations of neutron diffraction for magnetic structures and thermal expansion; no free parameters, ad-hoc axioms, or new entities are introduced in the abstract.

axioms (1)
  • standard math Neutron diffraction patterns can be indexed to determine magnetic propagation vectors and ordering temperatures in rare-earth and transition-metal sublattices.
    Invoked to assign the observed magnetic peaks to Eu antiferromagnetism and Fe SDW.

pith-pipeline@v0.9.0 · 5756 in / 1207 out tokens · 27709 ms · 2026-05-25T19:08:08.575494+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

37 extracted references · 37 canonical work pages · 1 internal anchor

  1. [1]

    Due to the large neutron absorption cross-section of Eu, the incident neutr on wavelength of 1.28 ◦ A was selected for the measurement. To investigate the evolution of the structure and magnetic ord er of EuFe 2As2 with hydrostatic pressure, a clamped pressure cell equipped with a cylinder-shaped sample holder was used . A mixture of ethanol and methanal ...

    work page

  2. [2]

    Kamihara, T

    Y . Kamihara, T. Watanabe, M. Hirano, and H. Hosono, J. Am. Chem. Soc. 130, 3296 (2008)

    work page 2008

  3. [3]

    D. C. Johnston, Advances in Physics 59, 803(2010), and refer- ences therein

    work page 2010

  4. [4]

    C. W. Chu, B. Lorenz, Physica C 469(2009)385

    work page 2009

  5. [5]

    A. S. Sefat, Rep. Prog. Phys. 74(2011)124502

    work page 2011

  6. [6]

    S. A. J. Kimber, A. Kreyssig, Y .-Z. Zhang, H. O. Jeschke, R . V alenti, F. Y okaichiya, E. Colombier, J. Yan, T. C. Hansen, T . Chatterji, R. J. McQueeney, P . C. Canfield, A. I. Goldman and D. N. Argyriou, Nature Materials 8, 471 - 475 (2009)

    work page 2009

  7. [7]

    Kreyssig, M

    A. Kreyssig, M. A. Green, Y . Lee, G. D. Samolyuk, P . Zajdel , J. W. Lynn, S. L. Bud’ko, M. S. Torikachvili, N. Ni, S. Nandi, J. B. Leao,3 S. J. Poulton, D. N. Argyriou, B. N. Harmon, R. J. McQueeney, P . C. Canfield, and A. I. Goldman, Phys. Rev. B 78, 184517 (2008)

    work page 2008

  8. [8]

    A. I. Goldman, A. Kreyssig, K. Prokes, D. K. Pratt, D. N. Ar - gyriou, J. W. Lynn, S. Nandi, S. A. J. Kimber, Y . Chen, Y . B. Lee, G. Samolyuk, J. B. Leao, S. J. Poulton, S. L. Bud’ko, N. Ni, P . C. Canfield, B. N. Harmon, and R. J. McQueeney, Phys. Rev. B 79, 024513 (2009)

    work page 2009

  9. [9]

    Prokes, A

    K. Prokes, A. Kreyssig, B. Ouladdiaf, D. K. Pratt, N. Ni, S . L. Bud’ko, P . C. Canfield, R. J. McQueeney, D. N. Argyriou, and A. I. Goldman, Phys. Rev. B 81, 180506(R) (2010)

    work page 2010

  10. [10]

    J. J. Wu, Jung-Fu Lin, X. C. Wang, Q. Q. Liu, J. L. Zhu, Y . M. Xiao, P . Chow, and C. Jin, Proc. Natl. Acad. Sci. USA 110, 17263 (2013)

    work page 2013

  11. [11]

    Tomic, Harald O

    M. Tomic, Harald O. Jeschke, Rafael M. Fernandes, and Ro ser V alenti, Phys. Rev. B87, 174503 (2013)

    work page 2013

  12. [12]

    Zapf and M

    S. Zapf and M. Dressel, Rep. Prog. Phys. 80, 016501 (2017)

    work page 2017

  13. [13]

    Raffius, E

    H. Raffius, E. Mörsen, B. D. Mosel, W. Müller-Warmuth, W. Jeitschko, L. Terbüchte, and T. V omhof, J. Phys. Chem. Solid s 54, 135 (1993)

    work page 1993

  14. [14]

    H. S. Jeevan, Z. Hossain, D. Kasinathan, H. Rosner, C. Ge ibel, and P . Gegenwart, Phys. Rev. B78, 052502 (2008)

    work page 2008

  15. [15]

    Y . Xiao, Y . Su, M. Meven, R. Mittal, C. M. N. Kumar, T. Chatterji, S. Price, J. Persson, N. Kumar, S. K. Dhar, A. Thamizhavel, and Th. Brueckel, Phys. Rev. B 80, 174424 (2009)

    work page 2009

  16. [16]

    C. F. Miclea, M. Nicklas, H. S. Jeevan, D. Kasinathan, Z. Hos- sain, H. Rosner, P . Gegenwart, C. Geibel, and F. Steglich, Phys. Rev. B 79, 212509 (2009)

    work page 2009

  17. [17]

    Terashima, M

    T. Terashima, M. Kimata, H. Satsukawa, A. Harada, K. Hazama, S. Uji, H. S. Suzuki, T. Matsumoto, and K. Murata, J. Phys. Soc. Jpn. 78, 083701 (2009)

    work page 2009

  18. [18]

    Kurita, M

    N. Kurita, M. Kimata, K. Kodama, A. Harada, M. Tomita, H. S. Suzuki, T. Matsumoto, K. Murata, S. Uji, and T. Terashima, Phys. Rev. B 83, 214513 (2011)

    work page 2011

  19. [19]

    Matsubayashi, K

    K. Matsubayashi, K. Munakata, M. Isobe, N. Katayama, K. Oh- gushi, Y . Ueda, N. Kawamura, M. Mizumaki, N. Ishimatsu, M. Hedo, I. Umehara, and Y . Uwatoko, Phys. Rev. B 84, 024502 (2011)

    work page 2011

  20. [20]

    Uhoya, G

    W. Uhoya, G. Tsoi, Y . K. V ohra, M. A. McGuire, A. S. Sefat,B. C. Sales, D. Mandrus, and S. T. Weir, J. Phys. Condens. Matter 22, 292202 (2010)

    work page 2010

  21. [21]

    W. T. Jin, J. P . Sun, G. Z. Ye, Y . Xiao, Y . Su, K. Schmazl, S. Nandi, Z. Bukowski, Z. Guguchia, E. Feng, et al., Sci. Rep. 7, 3532 (2017)

    work page 2017

  22. [22]

    D. L. Decker, J. Appl. Phys. 36, 157 (1965)

    work page 1965

  23. [23]

    D. K. Pratt, W. Tian, A. Kreyssig, J. L. Zarestky, S. Nand i, N. Ni, S. L. Bud’ko, P . C. Canfield, A. I. Goldman, and R. J. Mc- Queeney, Phys. Rev. Lett. 103, 087001 (2009)

    work page 2009

  24. [24]

    Nandi, M

    S. Nandi, M. G. Kim, A. Kreyssig, R. M. Fernandes, D. K. Pratt, A. Thaler, N. Ni, S. L. Bud’ko, P . C. Canfield, J. Schmalian, R. J. McQueeney, and A. I. Goldman, Phys. Rev. Lett. 104, 057006 (2010)

    work page 2010

  25. [25]

    X. Lu, H. Gretarsson, R. Zhang, X. Liu, H. Luo, W. Tian, M. Laver, Z. Yamani, Y .-J. Kim, A. H. Nevidomskyy, Q. Si, and P . Dai, Phys. Rev. Lett. 110, 257001 (2013)

    work page 2013

  26. [26]

    W. T. Jin, Y . Xiao, Y . Su, S. Nandi, W. H. Jiao, G. Nisbet, S . 6 Demirdis, G. H. Cao, and T. Brückel, Phys. Rev. B 93, 024517 (2016)

    work page 2016

  27. [27]

    W. T. Jin, Y . Xiao, Z. Bukowski, Y . Su, S. Nandi, A. P . Sazonov, M. Meven, O. Zaharko, S. Demirdis, K. Nemkovski, et al., Phys. Rev. B 94, 184513 (2016)

    work page 2016

  28. [28]

    Fujii, Y

    Y . Fujii, Y . Soejima, A. Okazaki, I.K. Bdikin, G.A. Emel’chenko, A.A. Zhokhov, Physica C 377, 49 (2002)

    work page 2002

  29. [29]

    J. D. Jorgensen, D. G. Hinks, P . G. Radaelli, W. I. F. Davi d, R. M. Ibberson, arXiv:cond-mat/0205486 (2002)

    work page internal anchor Pith review Pith/arXiv arXiv 2002

  30. [30]

    Hardy, P

    F. Hardy, P . Adelmann, Th. Wolf, H.v. Loehneysen, and C. Meingast, Phys. Rev. Lett. 102, 187004 (2009)

    work page 2009

  31. [31]

    Z. Ren, Q. Tao, S. Jiang, C. Feng, C. Wang, J. Dai, G. Cao, a nd Z. Xu, Phys. Rev. Lett. 102, 137002 (2009)

    work page 2009

  32. [32]

    W. T. Jin, S. Nandi, Y . Xiao, Y . Su, O. Zaharko, Z. Guguchi a, Z. Bukowski, S. Price, W. H. Jiao, G. H. Cao, and Th. Brückel, Phys. Rev. B 88, 214516 (2013)

    work page 2013

  33. [33]

    Nandi, W

    S. Nandi, W. T. Jin, Y . Xiao, Y . Su, S. Price, D. K. Shukla, J. Strempfer, H. S. Jeevan, P . Gegenwart, and Th. Brückel, Phys . Rev. B 89, 014512 (2014)

    work page 2014

  34. [34]

    Nandi, W

    S. Nandi, W. T. Jin, Y . Xiao, Y . Su, S. Price, W. Schmidt, K . Schmalzl, T. Chatterji, H. S. Jeevan, P . Gegenwart, and Th. Brückel, Phys. Rev. B 90, 094407 (2014)

    work page 2014

  35. [35]

    W. T. Jin, W. Li, Y . Su, S. Nandi, Y . Xiao, W. H. Jiao, M. Meven, A. P . Sazonov, E. Feng, Y . Chen, C. S. Ting, G. H. Cao, and Th. Brückel, Phys. Rev. B 91, 064506 (2015)

    work page 2015

  36. [36]

    W.-H. Jiao, Q. Tao, Z. Ren, Y . Liu, and G.-H. Cao, npj Quantum Materials 2, 50 (2017)

    work page 2017

  37. [37]

    H. S. Jeevan, Z. Hossain, Deepa Kasinathan, H. Rosner, C . Geibel, and P . Gegenwart, Phys. Rev. B 78, 092406 (2008)

    work page 2008