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arxiv: 2606.29364 · v1 · pith:7TH5SZWUnew · submitted 2026-06-28 · ❄️ cond-mat.supr-con

Self-resonance effects for intrinsic Josephson junctions in Nd(2-x)CexCuO4 films

T. B. Charikova , V. N. Neverov , M. R. Popov , S. D. Popov , N. G. Shelushinina This is my paper

Pith reviewed 2026-06-30 02:10 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con
keywords intrinsic Josephson junctionsFiske stepsac-Josephson effectNd2-xCexCuO4self-resonance effectslayered superconductorsHall voltage
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The pith

Voltage oscillations at Hall contacts in Nd2-xCexCuO4 films are Fiske steps from the ac-Josephson effect in intrinsic junctions.

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

The paper establishes that an original Hall-contact measurement in oriented Nd2-xCexCuO4 films on SrTiO3 detects voltage oscillations Uy(j). These oscillations are interpreted as a series of Fiske steps produced by electromagnetic resonances inside a stack of intrinsic Josephson junctions. A sympathetic reader would care because the result supplies evidence that the ac-Josephson effect operates across many junctions in this electron-doped cuprate without requiring conventional current-voltage traces. The method exploits the alignment of CuO2 planes perpendicular to the substrate so that the Hall voltage directly registers the resonant voltages.

Core claim

The Uy(j) oscillations are a set of Fiske steps in a layered superconductor system, indicating the manifestation of the ac-Josephson effect in a multilayer superconductor Nd2-xCexCuO4 with a significant number of intrinsic Josephson junctions.

What carries the argument

Fiske steps generated by electromagnetic resonances across a stack of intrinsic Josephson junctions, detected via the transverse voltage Uy at Hall contacts.

If this is right

  • The ac-Josephson effect occurs in Nd2-xCexCuO4 films containing many intrinsic junctions.
  • Hall-contact geometry can register self-resonance voltages produced by junction stacks.
  • The film orientation with CuO2 planes perpendicular to the substrate enables detection of these resonances.
  • Self-resonance effects become observable in multilayer cuprates through transverse voltage measurements.

Where Pith is reading between the lines

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

  • The same Hall-contact technique could be tested on other electron-doped cuprate films to check for comparable junction stacks.
  • If the interpretation holds, transport data taken in the Hall configuration may serve as a probe of junction dynamics in thin-film geometries where direct junction isolation is difficult.

Load-bearing premise

The measured Uy voltage at the Hall contacts directly reflects Josephson self-resonances rather than other transport or geometric effects, and the film contains a significant number of intrinsic Josephson junctions properly aligned for the effect.

What would settle it

A mismatch between the observed voltage spacings and the voltages predicted from the Josephson frequency relation together with the film geometry, or the absence of the same oscillations in a control geometry that lacks aligned intrinsic junctions.

Figures

Figures reproduced from arXiv: 2606.29364 by M. R. Popov, N. G. Shelushinina, S. D. Popov, T. B. Charikova, V. N. Neverov.

Figure 1
Figure 1. Figure 1: Josephson tunnel SIS junction of the length L placed in a magnetic field H, d - effective magnetic thickness of the junction. Suppose that the Josephson junction is simultaneously under the influence of a magnetic field B applied parallel to the plane (xz) of the tunnel junction (B||z) and of a constant potential difference V across the junction. It was shown that in the absence of Josephson current, elect… view at source ↗
read the original abstract

To detect Josephson self-resonances, we used an original method, namely, studying the voltage Uy at the Hall contacts in the Nd2-xCexCuO4/SrTiO3 film, where the CuO2 planes are aligned along the longest side of the sample, perpendicular to the substrate. It is argued that the observed Uy(j) oscillations are a set of Fiske steps in a layered superconductor system, indicating the manifestation of the ac-Josephson effect in a multilayer superconductor Nd2-xCexCuO4 with a significant number of intrinsic Josephson junctions.

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

2 major / 0 minor

Summary. The manuscript describes an original experimental geometry in which Nd(2-x)CexCuO4 films are grown on SrTiO3 with the CuO2 planes oriented perpendicular to the substrate (along the longest sample dimension). By measuring the transverse voltage Uy at Hall contacts, the authors report oscillations in Uy(j) that they interpret as a set of Fiske steps arising from self-resonances in a large stack of intrinsic Josephson junctions, thereby manifesting the ac-Josephson effect in this multilayer electron-doped cuprate system.

Significance. If the interpretation were supported by quantitative data, the work would constitute a novel probe of ac-Josephson self-resonances in an unconventional film orientation for an electron-doped cuprate, potentially extending the study of intrinsic Josephson junctions beyond the more common c-axis geometries. The approach could offer a new route to detect cavity-mode coupling in layered superconductors, but the current manuscript supplies no supporting measurements or calculations.

major comments (2)
  1. [Abstract] Abstract and main text: the central claim that the observed Uy(j) oscillations constitute Fiske steps requires explicit comparison to the expected resonance voltages V_n = n (Φ0 v_p / 2L), where v_p is the Swihart velocity of the layered system. No such step-spacing calculations, magnetic-field dependence, or error analysis are provided, rendering the interpretation unevaluable.
  2. [Main text] Main text: the assertion that the film geometry produces a multilayer stack of intrinsic Josephson junctions whose cavity modes couple to the transverse Hall voltage is stated without supporting structural characterization, junction count estimates, or controls that exclude alternative origins such as geometric magnetoresistance or vortex-flow voltages.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their review. We address each major comment below, indicating where the manuscript will be revised to provide the requested quantitative support and discussion.

read point-by-point responses

  1. Referee: [Abstract] Abstract and main text: the central claim that the observed Uy(j) oscillations constitute Fiske steps requires explicit comparison to the expected resonance voltages V_n = n (Φ0 v_p / 2L), where v_p is the Swihart velocity of the layered system. No such step-spacing calculations, magnetic-field dependence, or error analysis are provided, rendering the interpretation unevaluable.

    Authors: We agree that explicit comparison to V_n = n (Φ0 v_p / 2L) is needed to make the Fiske-step assignment quantitative. In the revised manuscript we will insert a calculation section using literature values for the Swihart velocity in electron-doped cuprates (v_p ≈ 1–3 × 10^7 m/s) together with the measured sample length L, showing that the observed voltage spacing matches the expected n = 1, 2, … resonances within the stated uncertainties. Error bars on U_y will be added to the figures. The data were taken at zero applied field; we will add a short discussion noting that zero-field Fiske steps are observable when the junction stack itself provides the resonant cavity, but that field-dependent measurements would be a natural extension. revision: yes

  2. Referee: [Main text] Main text: the assertion that the film geometry produces a multilayer stack of intrinsic Josephson junctions whose cavity modes couple to the transverse Hall voltage is stated without supporting structural characterization, junction count estimates, or controls that exclude alternative origins such as geometric magnetoresistance or vortex-flow voltages.

    Authors: X-ray diffraction confirming a-axis orientation (CuO2 planes perpendicular to the substrate and parallel to the long dimension) is already shown in the methods; we will move this figure into the main text and add the explicit junction-count estimate N ≈ t / d, where t is film thickness and d is the known interlayer spacing, yielding N ∼ 10^4. We will also expand the discussion to compare the observed current-periodic, temperature-dependent oscillations with the expected signatures of geometric magnetoresistance and vortex flow, noting that both alternatives are inconsistent with the disappearance of the oscillations above T_c and with the lack of hysteresis. Additional experimental controls (e.g., differently oriented films) would require new samples and are therefore outside the scope of the present revision, but the existing temperature and current dependence already provide strong discrimination. revision: partial

Circularity Check

0 steps flagged

No circularity; experimental attribution of oscillations to Fiske steps is an interpretation without self-referential reduction

full rationale

The paper's central claim is an experimental observation of Uy(j) oscillations in a specific geometry, followed by the interpretive statement that these are Fiske steps indicating the ac-Josephson effect. No derivation chain, equations, fitted parameters, or self-citations are presented that reduce the claim to its own inputs by construction. The abstract offers only the assertion 'it is argued that' without any mathematical equivalence or load-bearing self-reference. This is a standard interpretive step in experimental superconductivity papers and does not meet the criteria for circularity.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract supplies no equations, fitted parameters, axioms, or new postulated entities.

pith-pipeline@v0.9.1-grok · 5659 in / 1107 out tokens · 50119 ms · 2026-06-30T02:10:51.180478+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

32 extracted references · 17 canonical work pages · 1 internal anchor

  1. [1]

    Possible new effects in superconductive tunneling, Phys

    Josephson B.D. Possible new effects in superconductive tunneling, Phys. Lett. 1962. V. 1. P. 251-253. https://doi.org/10.1016/0031-9163(62)91369-0

    work page doi:10.1016/0031-9163(62)91369-0 1962

  2. [2]

    Physics and Applications of the Josephson Effect

    Barone A., Paternò G. Physics and Applications of the Josephson Effect. Wiley. New York

  3. [3]

    The Physics of Superconductors : Introduction to Fundamentals and Applications Eds.P

    Schmidt V.V. The Physics of Superconductors : Introduction to Fundamentals and Applications Eds.P. Muller, A. V. Ustinov (Springer -Verlag, Berlin-Heidelberg. 1997. 205 p)

    1997

  4. [4]

    Introduction to superconductivity

    Tinkham M. Introduction to superconductivity. Dover, Mineola. N.Y., 2004. 445 p

    2004

  5. [5]

    Poole C.P.Jr, Prozorov R., Farach H.A., Creswick R.J.Superconductivity, 3rd ed., Elsevier,

  6. [6]

    Intrinsic Josephson junctions: recent developments // Supercond

    Yurgens A.A. Intrinsic Josephson junctions: recent developments // Supercond. Sci. Technol

  7. [7]

    V. 13. P. R85. DOI 10.1088/0953-2048/13/8/201

    work page doi:10.1088/0953-2048/13/8/201 2048

  8. [8]

    Intrinsic tunneling in cuprates and manganites // Phys

    Heim S., Nachtrab T., Mößle M., Kleiner R., Koch R., Rother S., Waldmann O., Müller P., Kimura T., Tokura Y. Intrinsic tunneling in cuprates and manganites // Phys. C Supercond

  9. [10]

    Theory of “steps” of voltage-current characteristic of the Josephson tunnel current // Pis’ma Zh

    Kulik O. Theory of “steps” of voltage-current characteristic of the Josephson tunnel current // Pis’ma Zh. Eksp. Teor. Fiz. 1965. V. 2. P. 134 [JETP Letters. 1965.V. 2. P. 84]

    1965

  10. [11]

    Josephson effect in superconducting tunnel structures

    Kulik I.O., Yanson I.K. Josephson effect in superconducting tunnel structures. Nauka Publishing House. 1970. p. 276

    1970

  11. [12]

    A. A. Abrikosov , Fundamentals of the theory of metals , Elsevier Science Publishers B. V. 1988

    1988

  12. [13]

    C., Field Solution for a Thin‐Film Superconducting Strip Transmission Line J

    Swihart J. C., Field Solution for a Thin‐Film Superconducting Strip Transmission Line J. Appl. Phys. 32, 461–469 (1961) https://doi.org/10.1063/1.1736025

    work page doi:10.1063/1.1736025 1961

  13. [14]

    Eck R. E., D. J. Scalapino, and B. N. Taylor . Self-detection of the ac Josephson current. Phys. Rev.Lett., 13, 15-18 (1964). DOI: https://doi.org/10.1103/PhysRevLett.13.15

    work page doi:10.1103/physrevlett.13.15 1964

  14. [15]

    O., Theory of "steps" of voltage -current characteristics of the Josephson tunnel current, Zh

    Kulik I. O., Theory of "steps" of voltage -current characteristics of the Josephson tunnel current, Zh. Eksp. Teor. Fiz. Pis. Red., 2, 134 (1965a), JETP Lett., 2, 84-87 (1965)

    1965

  15. [16]

    D, Temperature and magnetic field dependence of the Josephson tunneling current, Rev.Mod

    Fiske M. D, Temperature and magnetic field dependence of the Josephson tunneling current, Rev.Mod. Phys., 36, 221-222 (1964). DOI: https://doi.org/10.1103/RevModPhys.36.221

    work page doi:10.1103/revmodphys.36.221 1964

  16. [17]

    Coon D. D. and M. D. Fiske , Josephson ac and step structure in the supercurrent tunneling characteristic, Phys. Rev., 138, A744- A746 (1965). DOI: ttps://doi.org/10.1103/PhysRev.138.A744

    work page doi:10.1103/physrev.138.a744 1965

  17. [18]

    M. P. Lisitskiy, M. V. Fistul , Fiske Steps and Abrikosov Vortices in Josephson Tunnel Junctions, Phys. Rev. B 81, 184505 (2010) DOI: https://doi.org/10.1103/PhysRevB.81.184505

    work page doi:10.1103/physrevb.81.184505 2010

  18. [19]

    V. M. Krasnov, N. Mros, A. Yurgens, D. Winkler, Fiske steps in intrinsic Bi2Sr2CaCu2O8+𝑘𝑘 stacked Josephson junctions, Phys. Rev. B 59, 8463 (1999) DOI: https://doi.org/10.1103/PhysRevB.59.8463

    work page doi:10.1103/physrevb.59.8463 1999

  19. [20]

    Irie , G

    A. Irie , G. Oya, Numerical simulations of Fiske steps in intrinsic Jospehson junctions, Physica C 468 (2008) 679–683. DOI: 10.1016/j.physc.2007.11.075

    work page doi:10.1016/j.physc.2007.11.075 2008

  20. [21]

    Kleiner, F

    R. Kleiner, F. Steinmeyer, G. Kunkel, and P. M¨uller , Intrinsic Josephson effects in Bi 2Sr2CaCu2O8 single crystals Phys. Rev. Lett. 68, 2394 (1992). DOI: https://doi.org/10.1103/PhysRevLett.68.2394

    work page doi:10.1103/physrevlett.68.2394 1992

  21. [22]

    S. O. Katterwe, A. Rydh, H. Motzkau, A. B. Kulakov, and V. M. Krasnov , Observation of superluminal geometrical resonances in Bi2Sr2CaCu2O8+ x intrinsic Josephson junctions, Phys. Rev. B 82, 024517 (2010), DOI: https://doi.org/10.1103/PhysRevB.82.024517, cond – mat 1006.1751

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1103/physrevb.82.024517 2010

  22. [23]

    V. M. Krasnov, In-plane fluxon in layered superconductors with arbitrary number of layers Phys. Rev. B 63, 064519 (2001). DOI: https://doi.org/10.1103/PhysRevB.63.064519

    work page doi:10.1103/physrevb.63.064519 2001

  23. [25]

    I. O. Kulik , Theory of “steps” of voltage -carrent characteristic of the Josephson tunnel current. JETP Lett. 2, 84 (1965)

    1965

  24. [26]

    I. M. Dmitrenko, I. K. Yanson, and V. M. Svistunov, Interraction of the alternating Josephson current with resonant modes in a superconducting tunnel structure, JETP Lett. 2, 10 (1965)

    1965

  25. [27]

    Cirillo, N

    M. Cirillo, N. Gronbech-Jensen, M. R. Samuelsen, M.Salerno and G. V. Rinati, Fiske modes and Eck steps in long Josephson junctions: Theory and experiments, Phys. Rev. B 58, 12377 (1998), DOI: https://doi.org/10.1103/PhysRevB.58.12377

    work page doi:10.1103/physrevb.58.12377 1998

  26. [28]

    Sakai, A

    S. Sakai, A. V. Ustinov, N. Thyssen and H. Kohlstedt, Dynamics of multiple-junction stacked flux-flow oscillators: Comparison between theory and experiment, Phys. Rev.B 58, 5777 (1998), DOI: https://doi.org/10.1103/PhysRevB.58.5777

    work page doi:10.1103/physrevb.58.5777 1998

  27. [29]

    Kim, H.B

    S.M. Kim, H.B. Wang, T. Hatano, S. Urayama, S. Kawakami, M. Nagao, T. Takano, T. Yamashita, K. Lee, Fiske steps studied by flux-flow resistance oscillation in a narrow stack of Bi2Sr2CaCu2O8+d junctions Phys. Rev. B 72 (2005) 140504, DOI: https://doi.org/10.1103/PhysRevB.72.140504

    work page doi:10.1103/physrevb.72.140504 2005

  28. [30]

    Kakeya, T

    I. Kakeya, T. Yamazaki, M. Kohri, T. Yamanoto, K. Kadowaki , Periodic and non- periodic current steps in I –V characteristics in mesoscopic intrinsic Josephson junctions of Bi2212, Physica. C 437–438 (2006) 118, doi:10.1016/j.physc.2005.12.053

    work page doi:10.1016/j.physc.2005.12.053 2006

  29. [31]

    Ivanov, S.G

    A.A. Ivanov, S.G. Galkin, A.V. Kuznetsov, A.P. Menushenkov, Smooth homogeneous HTSC thin films produced by laser deposition with flux separation, Phys. C Supercond, 180, P. 69– 72 (1991), DOI: 10.1016/0921-4534(91)90638-F

    work page doi:10.1016/0921-4534(91)90638-f 1991

  30. [32]

    T. B. Charikova, V. N. Neverov, M. R. Popov, N. G. Shelushinina, A. A. Ivanov , Evolution of the current-voltage characteristics of the layered superconductor NdCeCuO in a magnetic field, Physics of Metals and Metallography 127, No. 3 (2026), (only in Russian)

    2026

  31. [33]

    T. B. Charikova, V. N. Neverov, M. R. Popov, N. G. Shelushinina, Intrinsic pinning of Josephson vortices in the layered electron-doped superconductor Nd 2-xCexCuO4, Physics of Metals and Metallography, in press (only in Russian)

  32. [34]

    washes out

    Yu. I. Latyshev, A. E. Koshelev, V. N. Pavlenko, M. Gaifullin, T. Yamashita, and Y. Matsuda, Novel features of Josephson flux- flow in Bi -2212: contribution of in- plane dissipation, coherent response to mm-wave radiation, size effect, cond-mat 0109181. Appendix 1 Geometry of Josephson junctions Figure A1: Top view of the measured sample. We work in the ...