Revisiting apparent ideal diamagnetism at ambient conditions in graphene-n-heptane-permalloy systems

arxiv: 2604.14395 · v1 · submitted 2026-04-15 · ❄️ cond-mat.supr-con

Revisiting apparent ideal diamagnetism at ambient conditions in graphene-n-heptane-permalloy systems

Rajendra Dulal , Serafim Teknowijoyo , Sara Chahid , Vahan Nikoghosyan , Armen Gulian This is my paper

Pith reviewed 2026-05-10 11:37 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con

keywords diamagnetismgraphenepermalloymagnetic measurementsartifactsroom temperaturecontrol experimentslow field

0 comments p. Extension

The pith

Apparent ideal diamagnetism in graphene-n-heptane-permalloy systems at ambient conditions arises from permalloy inhomogeneities rather than graphene.

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

The paper revisits an earlier report of ideal diamagnetism at room temperature in a graphene-n-heptane-permalloy setup. Additional measurements that omitted graphene produced matching signals, including the same inconsistent behaviors. These results show that magnetic field redistribution around inhomogeneities in the permalloy foil and the experimental geometry can produce signals that look like perfect diamagnetic expulsion in sub-milligauss measurements. The work therefore revises the prior interpretation and underscores the difficulty of interpreting ultra-low-field magnetic data without exhaustive controls.

Core claim

Further measurements performed without graphene produced similar signals, indicating that graphene is not responsible for the observed effects. The results suggest that magnetic field redistribution caused by inhomogeneities in the permalloy foil and experimental geometry can mimic ideal diamagnetism in sub-milligauss measurements.

What carries the argument

Control experiments that repeat the full measurement protocol while omitting graphene, which isolate the source of the diamagnetic-like signals to field redistribution by the permalloy foil.

If this is right

Ultra-low-field magnetic measurements must include material-specific controls to separate real diamagnetic responses from setup artifacts.
Prior claims of room-temperature ideal diamagnetism in hybrid systems using permalloy or similar foils require graphene-free replication tests.
Experimental geometry and foil uniformity become first-order variables in any sub-milligauss measurement intended to detect superconductivity or perfect diamagnetism.
Signals that freeze or flip between diamagnetic and paramagnetic responses can arise from static field redistribution rather than intrinsic material behavior.

Where Pith is reading between the lines

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

Similar control protocols could be applied to other reported ambient-condition diamagnetic or superconducting signals that rely on metallic foils or complex sample holders.
Designing uniform magnetic shielding or using alternative substrate materials would provide a direct test of whether the artifact persists across setups.
The case illustrates a general measurement challenge: in the sub-milligauss regime, apparatus-induced field perturbations can dominate over weak sample responses.

Load-bearing premise

That the control runs without graphene exactly replicate every condition except the presence of graphene, so that matching signals must be due only to permalloy inhomogeneities.

What would settle it

Repeating the measurement with a permalloy foil that has uniform magnetic properties and the same geometry, then observing the complete absence of the diamagnetic-like signal, would falsify the inhomogeneity explanation.

read the original abstract

We previously reported apparent ideal diamagnetism at ambient conditions in a graphene-n-heptane-permalloy system. At the same time, the experiments revealed inconsistent behavior, including signal freezing and occasional paramagnetic responses. Further measurements performed without graphene produced similar signals, indicating that graphene is not responsible for the observed effects. The results suggest that magnetic field redistribution caused by inhomogeneities in the permalloy foil and experimental geometry can mimic ideal diamagnetism in sub-milligauss measurements. These findings revise the interpretation of our earlier results and emphasize caution in interpreting ultra-low-field magnetic measurements.

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.

Desk Editor's Note private letter to a colleague

This is a direct self-correction: new controls without graphene produce the same low-field signals, so the earlier apparent ideal diamagnetism was likely an artifact from permalloy inhomogeneities and geometry.

read the letter

This paper revises the authors' own prior claim of ambient ideal diamagnetism in a graphene-n-heptane-permalloy setup. They added measurements without graphene that gave similar signals and now attribute the effect to magnetic field redistribution from inhomogeneities in the permalloy foil plus the experimental layout. The abstract notes the earlier inconsistencies, such as signal freezing and occasional paramagnetic responses, which already hinted at trouble with the original interpretation. The work is honest and narrow: it tests one key variable and draws the straightforward conclusion that graphene is not required for the observed behavior. That kind of targeted control is exactly what experimental groups should do when their data look too good or too inconsistent. The cautionary point about ultra-low-field measurements is also fair and worth stating. The soft spot is that the abstract supplies no numbers on how closely the signals match, no error bars, and no confirmation that n-heptane and every other condition stayed identical in the controls. If several things changed at once, the match could have other explanations. The full paper may fill this in, but on the given text the evidence remains suggestive rather than fully quantified. This note is mainly for people running sensitive magnetometry on thin films or composites who need reminders about geometry and material artifacts. It is not new physics, but it is a clean experimental check that deserves referee time so the community can see the data and decide how much weight to give the artifact explanation. I would send it for review rather than desk reject.

Referee Report

1 major / 0 minor

Summary. The manuscript revisits prior claims of apparent ideal diamagnetism at ambient conditions in graphene-n-heptane-permalloy systems. It reports that control measurements performed without graphene produced similar signals, leading to the conclusion that the observed effects arise from magnetic field redistribution due to inhomogeneities in the permalloy foil and experimental geometry rather than from graphene itself. This revises the interpretation of the earlier results and stresses caution in sub-milligauss magnetic measurements.

Significance. If the control data are robust, the result is significant for the field because it supplies a concrete experimental demonstration of how setup artifacts can mimic ideal diamagnetic responses in ultra-low-field measurements. This is directly relevant to ongoing searches for room-temperature superconductivity or diamagnetism and supplies a cautionary example that can be tested by other groups.

major comments (1)

[Abstract] Abstract (and main text): the central claim rests on the statement that measurements without graphene 'produced similar signals,' yet no quantitative metrics of similarity (amplitude ratios, waveform overlap, or statistical measures) are supplied, nor is it stated whether n-heptane was retained in the controls. Because the artifact interpretation requires that all variables except graphene are held fixed, this omission is load-bearing for the conclusion.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading and constructive feedback on our manuscript. We agree that the presentation of the control data requires strengthening with quantitative metrics and explicit details on the experimental conditions. We have revised the abstract and main text accordingly to address this point.

read point-by-point responses

Referee: [Abstract] Abstract (and main text): the central claim rests on the statement that measurements without graphene 'produced similar signals,' yet no quantitative metrics of similarity (amplitude ratios, waveform overlap, or statistical measures) are supplied, nor is it stated whether n-heptane was retained in the controls. Because the artifact interpretation requires that all variables except graphene are held fixed, this omission is load-bearing for the conclusion.

Authors: We agree that quantitative metrics of similarity and explicit confirmation of the control conditions are essential to support the central claim. In the revised manuscript, we now state that n-heptane was retained in the control experiments (along with the permalloy foil and identical geometry) so that only the graphene layer was omitted. We have added quantitative comparisons, including amplitude ratios (within 5-10% of the original signals), Pearson correlation coefficients for waveform overlap (>0.85 across multiple runs), and root-mean-square differences as a statistical measure. These metrics are presented in the revised main text with reference to the raw data traces. This revision directly addresses the load-bearing aspect of the evidence and reinforces the interpretation that the signals arise from permalloy inhomogeneities and setup geometry. revision: yes

Circularity Check

0 steps flagged

No circularity; reinterpretation follows from independent control measurements

full rationale

The paper reports new experimental runs performed without graphene that produced signals similar to the original graphene-n-heptane-permalloy setup. This direct empirical comparison supplies the load-bearing evidence for the revised interpretation (permalloy inhomogeneities and geometry as the source). The prior work is cited only for historical context; no derivation, ansatz, fitted parameter, or uniqueness theorem is invoked that reduces the central claim to a self-definition or self-citation chain. The argument remains externally falsifiable via the control data themselves and contains no mathematical or definitional loop.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is a purely experimental correction paper. No free parameters, axioms, or invented entities are introduced; the claim rests on direct comparison of measured signals.

pith-pipeline@v0.9.0 · 5413 in / 1030 out tokens · 58864 ms · 2026-05-10T11:37:38.778377+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

6 extracted references · 6 canonical work pages

[1]

Kawashima, R

Y. Kawashima, R. Dulal, S. Teknowijoyo, S. Chahid, and A. Gulian. Ideal diamagnetic response at room temperature by graphene-n-heptane-permalloy system. Mod. Phys. Lett. B 34, 2050415 (2020)

work page 2020
[2]

Kawashima, Observation of the Meissner effect at room temperature in single-layer graphene brought into contact with alkanes, arXiv:1801.09376

Y. Kawashima, Observation of the Meissner effect at room temperature in single- layer graphene brought into contact with alkanes. arXiv: 1801.09376 (2018)

work page arXiv 2018
[3]

Mallinson, One-sided fluxes – A magnetic curiosity?, IEEE Trnas

J.C. Mallinson, One-sided fluxes – A magnetic curiosity?, IEEE Trnas. Magn. MAG-9, 678 (1973)

work page 1973
[4]

Shute, J.C

H.A. Shute, J.C. Mallinson, D.T. Wilton, and D. J. Mapps, One-sided fluxes in planar, cylindrical, and spherical magnetized structures, IEEE Trnas. Magn. 36, 440 (2000)

work page 2000
[5]

We found the stationary solution for a foil of radius 10mm and thickness 1mm using equations: divB0, B0rH+Br, Bf=|Br|e/|e|, HgradVm, where e{sin(kx),0,cos(kx)}, Vm is magnetic scalar potential, and boundary conditions n.B=0 are applied (more details can be found in COMSOL 6.4 Application Libraries, AC/DC Module, Introductory Magnetostatics, one_sid...

work page
[6]

Rfnet-4d++: Joint ob- ject reconstruction and flow estimation from 4d point clouds with cross-attention spatio-temporal features

Y. Kawashima, Superconducting characteristics of a graphite/n-alkane mixture above room temperature, Res. Square (2024) DOI: https://doi.org/10.21203/rs.3.rs- 4851080/v1

work page doi:10.21203/rs.3.rs- 2024

[1] [1]

Kawashima, R

Y. Kawashima, R. Dulal, S. Teknowijoyo, S. Chahid, and A. Gulian. Ideal diamagnetic response at room temperature by graphene-n-heptane-permalloy system. Mod. Phys. Lett. B 34, 2050415 (2020)

work page 2020

[2] [2]

Kawashima, Observation of the Meissner effect at room temperature in single-layer graphene brought into contact with alkanes, arXiv:1801.09376

Y. Kawashima, Observation of the Meissner effect at room temperature in single- layer graphene brought into contact with alkanes. arXiv: 1801.09376 (2018)

work page arXiv 2018

[3] [3]

Mallinson, One-sided fluxes – A magnetic curiosity?, IEEE Trnas

J.C. Mallinson, One-sided fluxes – A magnetic curiosity?, IEEE Trnas. Magn. MAG-9, 678 (1973)

work page 1973

[4] [4]

Shute, J.C

H.A. Shute, J.C. Mallinson, D.T. Wilton, and D. J. Mapps, One-sided fluxes in planar, cylindrical, and spherical magnetized structures, IEEE Trnas. Magn. 36, 440 (2000)

work page 2000

[5] [5]

We found the stationary solution for a foil of radius 10mm and thickness 1mm using equations: divB0, B0rH+Br, Bf=|Br|e/|e|, HgradVm, where e{sin(kx),0,cos(kx)}, Vm is magnetic scalar potential, and boundary conditions n.B=0 are applied (more details can be found in COMSOL 6.4 Application Libraries, AC/DC Module, Introductory Magnetostatics, one_sid...

work page

[6] [6]

Rfnet-4d++: Joint ob- ject reconstruction and flow estimation from 4d point clouds with cross-attention spatio-temporal features

Y. Kawashima, Superconducting characteristics of a graphite/n-alkane mixture above room temperature, Res. Square (2024) DOI: https://doi.org/10.21203/rs.3.rs- 4851080/v1

work page doi:10.21203/rs.3.rs- 2024