pith. sign in

arxiv: 2604.05806 · v1 · submitted 2026-04-07 · ❄️ cond-mat.mes-hall

Optically induced thermal demagnetization and switching of antiferromagnetic domains in NiO and CoO thin films

Maciej D\k{a}browski , Tong Wu , Connor R. J. Sait , Jia Xu , Paul S. Keatley , Yizheng Wu , Robert J. Hicken , Olena Gomonay This is my paper

Pith reviewed 2026-05-10 19:14 UTC · model grok-4.3

classification ❄️ cond-mat.mes-hall
keywords antiferromagnetic domainsall-optical switchingNiOCoOthermal demagnetizationdomain wall motionponderomotive forcethin films
0
0 comments X

The pith

Reversing a laser beam's thermal gradient toggles antiferromagnetic domains in NiO and CoO films without electric currents.

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

A single laser pulse thermally demagnetizes the antiferromagnetic layers in NiO/Pt and CoO/Pt films, causing a random redistribution of domains. Sweeping the focused beam creates a moving temperature gradient that exerts a ponderomotive force on domain walls, producing controlled motion and partial switching of the antiferromagnetic order. Reversing the sweep direction reverses the force and toggles the 90-degree domains back and forth. The process requires no electric current and works in fully compensated insulating antiferromagnets. A simple analytical model reproduces the observed wall motion as thermal pressure from the gradient.

Core claim

Temperature gradients generated by a moving laser beam exert a thermal pressure on domain walls in the form of a ponderomotive force. This force enables controlled, reversible toggling of 90° antiferromagnetic domains in NiO and CoO thin films solely by reversing the direction of the gradient, achieving all-optical switching without electric currents.

What carries the argument

Ponderomotive force from the temperature gradient of the sweeping laser beam, which applies thermal pressure to drive domain wall motion.

If this is right

  • A single laser pulse thermally demagnetizes the antiferromagnet and produces random domain redistribution.
  • Sweeping the laser beam induces controlled domain wall motion and partial switching of the antiferromagnetic order.
  • The 90° domains can be toggled reversibly by simply reversing the direction of the thermal gradient.
  • The switching occurs in insulating antiferromagnetic layers without requiring electric currents.
  • The effect is captured by an analytical model treating the gradient as a ponderomotive force on the walls.

Where Pith is reading between the lines

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

  • The same thermal-gradient drive might be tested in other insulating antiferromagnets such as MnO or FeO to check how material parameters affect the force strength.
  • Pairing the technique with femtosecond laser pulses could shorten the switching time below the nanosecond scale set by thermal diffusion.
  • The current-free nature of the process suggests possible use in hybrid optical circuits where heat flow replaces charge flow for domain control.
  • The model implies that the switching efficiency should depend on the speed of the beam sweep relative to the thermal diffusion length in the film.

Load-bearing premise

The observed domain wall motion is caused exclusively by the thermal pressure of the moving temperature gradient rather than by direct optical torques, photo-induced strain, or other non-thermal laser effects.

What would settle it

Domain walls continuing to move when the laser is held stationary or when the sample is heated uniformly without a spatial gradient would show that the mechanism is not the moving thermal gradient.

Figures

Figures reproduced from arXiv: 2604.05806 by Connor R. J. Sait, Jia Xu, Maciej D\k{a}browski, Olena Gomonay, Paul S. Keatley, Robert J. Hicken, Tong Wu, Yizheng Wu.

Figure 1
Figure 1. Figure 1: Domain structure images of thin CoO and NiO films before (top row) and after (bottom row) opti [PITH_FULL_IMAGE:figures/full_fig_p021_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: (a) Domain structure images acquired after sweeping the laser beam across the surface at a velocity of v = 100 µm/s along the [1¯10] axis, as indicated by the red arrows above the images. (b) Differential images [(ii)−(i) etc.] show that some of the domains can be switched back and forth (see e.g. the domains marked by the white ellipse). Red and blue contrast in the differential images correspond to switc… view at source ↗
Figure 3
Figure 3. Figure 3: (a) Schematic illustration showing the thermal gradient induced by the laser beam, and associated with it the ponderomotive force Fpond, exerting the pressure on the domain wall wall (marked in red). The domain structure image has been obtained from the CoO(8 nm)/Pt(2 nm) sample.(b-e) Snapshots of the calculated temperature gradient ∇T induced by the laser beam as it moves parallel to the Néel vector along… view at source ↗
Figure 4
Figure 4. Figure 4: (a) Displacement of the domain wall (along the coordinate X) as a function of time for a static (v = 0) and moving beams (v = 100 µm/s and v = 210 µm/s). Dashed lines show the displacement of the beam center (also along X, parallel to the domain wall motion), and the shaded regions represent the width of the laser spot. 24 [PITH_FULL_IMAGE:figures/full_fig_p024_4.png] view at source ↗
read the original abstract

We demonstrate all-optical manipulation of magnetic domains in NiO/Pt and CoO/Pt thin films with insulating antiferromagnetic layers. Using magneto-optical birefringence imaging, we show that even a single laser pulse can thermally demagnetize the antiferromagnet, leading to a random redistribution of domains. By sweeping the laser beam, controlled domain wall motion is induced, enabling partial switching of the antiferromagnetic order. The behavior is captured by an analytical model in which temperature gradients generated by the moving beam exert a thermal pressure on domain walls in the form of a ponderomotive force. Importantly, the 90$^{\circ}$ domains can be reversibly toggled solely by reversing the direction of the thermal gradient, demonstrating all-optical switching without the need for electric currents. These findings establish a route toward ultrafast optical manipulation of fully compensated antiferromagnets, with potential impact on non-volatile memory technologies and antiferromagnetic spintronics.

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 / 2 minor

Summary. The manuscript reports all-optical manipulation of antiferromagnetic domains in NiO/Pt and CoO/Pt thin films. Single focused laser pulses are shown to thermally demagnetize the antiferromagnet, producing random domain redistribution observable via magneto-optical birefringence imaging. Sweeping the laser beam induces controlled 90° domain-wall motion that is captured by an analytical model treating the laser-induced temperature gradient as a ponderomotive force acting on the walls. The key result is that the direction of domain-wall displacement reverses when the scan direction (and thus the thermal gradient) is reversed, enabling reversible all-optical toggling without electric currents.

Significance. If the mechanism is confirmed to be purely thermal, the work would establish a practical route to ultrafast, current-free optical control of fully compensated antiferromagnets, with direct relevance to antiferromagnetic spintronics and non-volatile memory. The provision of an analytical model for the thermal pressure is a positive feature; if the model is parameter-free and yields falsifiable predictions that match the data quantitatively, that would strengthen the contribution.

major comments (2)
  1. [Experimental results and discussion] The central claim that 90° domain-wall motion is driven exclusively by the ponderomotive force arising from the moving thermal gradient is load-bearing for the interpretation of reversible all-optical switching. The manuscript does not report control experiments that vary laser wavelength (at fixed absorption), polarization, or pulse duration to suppress possible photo-induced magnetoelastic strain or residual magneto-optical torques, nor does it compare observed wall velocities against an independent estimate of the thermal force derived from measured temperature profiles.
  2. [Analytical model] The analytical model is stated to capture the observed behavior, yet the manuscript provides no quantitative comparison (including error bars or goodness-of-fit metrics) between predicted domain-wall velocities and the measured values. Without such a comparison it remains unclear whether the model is predictive or has been adjusted post-hoc to the same data used to demonstrate reversibility.
minor comments (2)
  1. [Figures] Figure captions should explicitly state the laser fluence, scan speed, and number of pulses used for each panel so that the conditions for single-pulse demagnetization versus swept-beam motion can be directly compared.
  2. [Theory] The abstract refers to an 'analytical model' without free parameters; the main text should state all assumptions and boundary conditions of the derivation in a dedicated subsection.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and the constructive comments. We address each major point below and describe the revisions we will implement.

read point-by-point responses

  1. Referee: [Experimental results and discussion] The central claim that 90° domain-wall motion is driven exclusively by the ponderomotive force arising from the moving thermal gradient is load-bearing for the interpretation of reversible all-optical switching. The manuscript does not report control experiments that vary laser wavelength (at fixed absorption), polarization, or pulse duration to suppress possible photo-induced magnetoelastic strain or residual magneto-optical torques, nor does it compare observed wall velocities against an independent estimate of the thermal force derived from measured temperature profiles.

    Authors: We agree that explicit control experiments varying wavelength at fixed absorption, polarization, and pulse duration would further strengthen the case against non-thermal contributions. The reversal of domain-wall motion with scan direction remains difficult to reconcile with polarization- or magneto-optical-torque-driven mechanisms, as those would not invert sign upon gradient reversal. For the velocity comparison, we will add in the revision a quantitative estimate of the thermal force using temperature profiles obtained from finite-element thermal modeling calibrated against our measured heating data, together with error bars on the experimental wall velocities. revision: partial

  2. Referee: [Analytical model] The analytical model is stated to capture the observed behavior, yet the manuscript provides no quantitative comparison (including error bars or goodness-of-fit metrics) between predicted domain-wall velocities and the measured values. Without such a comparison it remains unclear whether the model is predictive or has been adjusted post-hoc to the same data used to demonstrate reversibility.

    Authors: We accept that a direct quantitative comparison is required. In the revised manuscript we will present a figure comparing the domain-wall velocities predicted by the analytical ponderomotive-force model against the experimentally measured values, including error bars on the data points and a goodness-of-fit metric (R²). Model parameters are taken from independently measured material constants and temperature-gradient magnitudes; no post-hoc fitting to the switching data will be performed. revision: yes

Circularity Check

0 steps flagged

No significant circularity; analytical model and experimental claims remain independent of fitted inputs or self-citations.

full rationale

The paper presents an analytical model for ponderomotive force arising from laser-induced temperature gradients acting on antiferromagnetic domain walls, then reports experimental observations of domain motion and reversible toggling upon gradient reversal. No equations, parameter-fitting procedures, or self-citation chains are described in the abstract or reader summary that would reduce the central claim to a tautology or to data used in constructing the model itself. The derivation chain therefore stands as self-contained, with the model serving as an independent explanatory framework rather than a re-expression of the observations.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review; the analytical model implicitly relies on standard heat-diffusion equations and domain-wall mobility assumptions whose parameters are not specified.

pith-pipeline@v0.9.0 · 5501 in / 1070 out tokens · 106187 ms · 2026-05-10T19:14:02.704060+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

57 extracted references · 57 canonical work pages

  1. [1]

    D.et al.All-optical magnetic recording with circularly polarized light.Phys

    Stanciu, C. D.et al.All-optical magnetic recording with circularly polarized light.Phys. Rev. Lett.99, 047601 (2007). 13

    work page 2007

  2. [2]

    Lambert, C.-H.et al.All-optical control of ferromagnetic thin films and nanostructures.Sci- ence345, 1337–1340 (2014)

    work page 2014

  3. [3]

    & Kimel, A

    Stupakiewicz, A., Szerenos, K., Afanasiev, D., Kirilyuk, A. & Kimel, A. V . Ultrafast nonther- mal photo-magnetic recording in a transparent medium.Nature542, 71–74 (2017)

    work page 2017

  4. [4]

    Banerjee, C.et al.Single pulse all-optical toggle switching of magnetization without gadolin- ium in the ferrimagnet mn2ruxga.Nature Communications11, 4444 (2020)

    work page 2020

  5. [5]

    D ˛ abrowski, M.et al.Transition metal synthetic ferrimagnets: Tunable media for all-optical switching driven by nanoscale spin current.Nano Lett.21, 9210–9216 (2021)

    work page 2021

  6. [6]

    Igarashi, J.et al.Optically induced ultrafast magnetization switching in ferromagnetic spin valves.Nature Materials22, 725–730 (2023)

    work page 2023

  7. [7]

    S.et al.Phononic switching of magnetization by the ultrafast barnett effect.Nature 628, 540–544 (2024)

    Davies, C. S.et al.Phononic switching of magnetization by the ultrafast barnett effect.Nature 628, 540–544 (2024)

    work page 2024

  8. [8]

    & Koopmans, B

    Pezeshki, H., Li, P., Lavrijsen, R., Heck, M. & Koopmans, B. Integrated magneto-photonic non-volatile multi-bit memory.Journal of Applied Physics136, 083908 (2024)

    work page 2024

  9. [9]

    Hadri, M. S. E., Hehn, M., Malinowski, G. & Mangin, S. Materials and devices for all-optical helicity-dependent switching.Journal of Physics D: Applied Physics50, 133002 (2017)

    work page 2017

  10. [10]

    Manz, S.et al.Reversible optical switching of antiferromagnetism in TbMnO3.Nature Photonics10, 653–656 (2016)

    work page 2016

  11. [11]

    Grigorev, V .et al.Optically triggered Néel vector manipulation of a metallic antiferromagnet Mn2Au under strain.ACS Nano(2022). 14

    work page 2022

  12. [12]

    Meer, H.et al.Laser-induced creation of antiferromagnetic 180-degree domains in NiO/Pt bilayers.Advanced Functional Materials33, 2213536 (2023)

    work page 2023

  13. [13]

    Wadley, P.et al.Electrical switching of an antiferromagnet.Science351, 587–590 (2016)

    work page 2016

  14. [14]

    & Saitoh, E

    Hou, D., Qiu, Z. & Saitoh, E. Spin transport in antiferromagnetic insulators: progress and challenges.NPG Asia Materials11, 35 (2019)

    work page 2019

  15. [15]

    B., Zhang, W

    Jungfleisch, M. B., Zhang, W. & Hoffmann, A. Perspectives of antiferromagnetic spintronics. Physics Letters A382, 865–871 (2018)

    work page 2018

  16. [16]

    Kampfrath, T.et al.Coherent terahertz control of antiferromagnetic spin waves.Nature Photonics5, 31 (2010)

    work page 2010

  17. [17]

    S., Slavin, A

    Khymyn, R., Lisenkov, I., Tiberkevich, V . S., Slavin, A. N. & Ivanov, B. A. Transformation of spin current by antiferromagnetic insulators.PRB93, 224421 (2016)

    work page 2016

  18. [18]

    Lebrun, R.et al.Tunable long-distance spin transport in a crystalline antiferromagnetic iron oxide.Nature561, 222–225 (2018)

    work page 2018

  19. [19]

    Jani, H.et al.Antiferromagnetic half-skyrmions and bimerons at room temperature.Nature 590, 74–79 (2021)

    work page 2021

  20. [20]

    PRL91, 137201 (2003)

    Altieri, S.et al.Magnetic dichroism and spin structure of antiferromagnetic NiO(001) films. PRL91, 137201 (2003)

    work page 2003

  21. [21]

    Arenholz, E., van der Laan, G., Chopdekar, R. V . & Suzuki, Y . Angle-dependentni 2+ x-ray magnetic linear dichroism: Interfacial coupling revisited.Phys. Rev. Lett.98, 197201 (2007). 15

    work page 2007

  22. [22]

    Li, J.et al.Continuous spin reorientation transition in epitaxial antiferromagnetic nio thin films.PRB84, 012406 (2011)

    work page 2011

  23. [23]

    Li, Q.et al.Activation of antiferromagnetic domain switching in exchange-coupled fe/coo/mgo(001) systems.Phys. Rev. B91, 134428 (2015)

    work page 2015

  24. [24]

    Li, Q.et al.Antiferromagnetic proximity effect in epitaxial coo/nio/mgo(001) systems.Sci- entific Reports6, 22355 (2016)

    work page 2016

  25. [25]

    Yang, M.et al.The effect of spin reorientation transition of antiferromagnetic NiO on the Py magnetic anisotropy in Py/NiO/CoO/MgO(001).Journal of Magnetism and Magnetic Mate- rials460, 6–11 (2018)

    work page 2018

  26. [26]

    Xu, J.et al.Imaging antiferromagnetic domains in nickel oxide thin films by optical birefrin- gence effect.PRB100, 134413 (2019)

    work page 2019

  27. [27]

    Xu, J.et al.Optical imaging of antiferromagnetic domains in ultrathin CoO(001) films.New Journal of Physics22, 083033 (2020)

    work page 2020

  28. [28]

    & Slavin, A

    Khymyn, R., Tiberkevich, V . & Slavin, A. Antiferromagnetic spin current rectifier.AIP Advances7, 055931 (2017)

    work page 2017

  29. [29]

    Yang, M.et al.Current switching of the antiferromagnetic néel vector in pd/coo/mgo(001). Phys. Rev. B106, 214405 (2022)

    work page 2022

  30. [30]

    Lee, K.et al.Superluminal-like magnon propagation in antiferromagnetic nio at nanoscale distances.Nature Nanotechnology(2021)

    work page 2021

  31. [31]

    Qiu, H.et al.Ultrafast spin current generated from an antiferromagnet.Nature Physics(2020). 16

    work page 2020

  32. [32]

    D ˛ abrowski, M.et al.Coherent transfer of spin angular momentum by evanescent spin waves within antiferromagnetic nio.Phys. Rev. Lett.124, 217201 (2020)

    work page 2020

  33. [33]

    24, 1471–1476 (2024)

    Schmitt, C.et al.Mechanisms of electrical switching of ultrathin coo/pt bilayers.Nano Lett. 24, 1471–1476 (2024)

    work page 2024

  34. [34]

    & Hubert, A

    Schäfer, R. & Hubert, A. A new magnetooptic effect related to non-uniform magnetization on the surface of a ferromagnet.physica status solidi (a)118, 271–288 (1990)

    work page 1990

  35. [35]

    Zhou, C., Xu, J., Wu, T. & Wu, Y . Perspective on imaging antiferromagnetic domains in thin films with the magneto-optical birefringence effect.APL Materials11, 080902 (2023)

    work page 2023

  36. [36]

    Zhu, J.et al.Antiferromagnetic spin reorientation transition in epitaxial Nio/CoO/MgO(001) systems.Phys. Rev. B90, 054403 (2014)

    work page 2014

  37. [37]

    Li, Q.et al.Multiple in-plane spin reorientation transitions inFe/CoObilayers grown on vicinalMgO(001).Phys. Rev. B91, 104424 (2015)

    work page 2015

  38. [38]

    Alders, D.et al.Temperature and thickness dependence of magnetic moments in nio epitaxial films.PRB57, 11623–11631 (1998)

    work page 1998

  39. [39]

    Kim, W.et al.Effect of nio spin orientation on the magnetic anisotropy of the fe film in epitaxially grown fe/nio/ag(001) and fe/nio/mgo(001).PRB81, 174416 (2010)

    work page 2010

  40. [40]

    Schmitt, C.et al.Identifying the domain-wall spin structure in antiferromagnetic nio/pt.Phys. Rev. B107, 184417 (2023)

    work page 2023

  41. [41]

    Zhu, J.et al.Strain-modulated antiferromagnetic spin orientation and exchange coupling in Fe/CoO(001).Journal of Applied Physics115, 193903 (2014). 17

    work page 2014

  42. [42]

    Baldrati, L.et al.Efficient spin torques in antiferromagneticCoO/Ptquantified by comparing field- and current-induced switching.Phys. Rev. Lett.125, 077201 (2020)

    work page 2020

  43. [43]

    & Bigot, J.-Y

    Beaurepaire, E., Merle, J.-C., Daunois, A. & Bigot, J.-Y . Ultrafast spin dynamics in ferromag- netic nickel.Phys. Rev. Lett.76, 4250–4253 (1996)

    work page 1996

  44. [44]

    URLhttps://arxiv.org/abs/2205 .02686

    Wust, S.et al.Indirect optical manipulation of the antiferromagnetic order of insulating nio by ultrafast interfacial energy transfer (2022). URLhttps://arxiv.org/abs/2205 .02686

    work page 2022

  45. [45]

    R.et al.Distinguishing charge transfer and lattice heat impacts on the ultrafast demagnetization in antiferromagnetic coo films.Applied Physics Letters127, 182401 (2025)

    Zhao, Z. R.et al.Distinguishing charge transfer and lattice heat impacts on the ultrafast demagnetization in antiferromagnetic coo films.Applied Physics Letters127, 182401 (2025)

    work page 2025

  46. [46]

    Wittmann, A.et al.Role of substrate clamping on anisotropy and domain structure in the canted antiferromagnetα−fe 2o3.Phys. Rev. B106, 224419 (2022)

    work page 2022

  47. [47]

    Meer, H.et al.Strain-induced shape anisotropy in antiferromagnetic structures.Phys. Rev. B 106, 094430 (2022)

    work page 2022

  48. [48]

    Mangin, S.et al.Engineered materials for all-optical helicity-dependent magnetic switching. Nat. Mater.13, 286 (2014)

    work page 2014

  49. [49]

    S.et al.Domain size criterion for the observation of all-optical helicity-dependent switching in magnetic thin films.Phys

    El Hadri, M. S.et al.Domain size criterion for the observation of all-optical helicity-dependent switching in magnetic thin films.Phys. Rev. B94, 064419 (2016)

    work page 2016

  50. [50]

    John, R.et al.Magnetisation switching of fept nanoparticle recording medium by femtosecond laser pulses.Scientific Reports7, 4114 (2017). 18

    work page 2017

  51. [51]

    van Hees, Y . L. W., van de Meugheuvel, P., Koopmans, B. & Lavrijsen, R. Deterministic all-optical magnetization writing facilitated by non-local transfer of spin angular momentum. Nature Communications11, 3835 (2020)

    work page 2020

  52. [52]

    V ., Kirilyuk, A., Tsvetkov, A., Pisarev, R

    Kimel, A. V ., Kirilyuk, A., Tsvetkov, A., Pisarev, R. V . & Rasing, T. Laser-induced ultrafast spin reorientation in the antiferromagnet tmfeo3.Nature429, 850 (2004)

    work page 2004

  53. [53]

    Tzschaschel, C.et al.Ultrafast optical excitation of coherent magnons in antiferromagnetic nio.PRB95, 174407 (2017)

    work page 2017

  54. [54]

    M.et al.Impulsive generation of coherent magnons by linearly polarized light in the easy-plane antiferromagnetfebo 3.PRL99, 167205 (2007)

    Kalashnikova, A. M.et al.Impulsive generation of coherent magnons by linearly polarized light in the easy-plane antiferromagnetfebo 3.PRL99, 167205 (2007)

    work page 2007

  55. [55]

    D., ROULET, A

    BRECHET, S. D., ROULET, A. & ANSERMET, J.-P. Magnetoelectric ponderomotive force. Modern Physics Letters B27, 1350150 (2013)

    work page 2013

  56. [56]

    Gomonay, O.et al.Structure, control, and dynamics of altermagnetic textures.npj Spintronics 2, 35 (2024)

    work page 2024

  57. [57]

    Wu, T., Chen, H., Ma, T., Xu, J. & Wu, Y . Current-density-modulated antiferromagnetic domain switching revealed by optical imaging in thePt/CoO(001)bilayer.Phys. Rev. Appl. 21, 044054 (2024). Acknowledgements M.D., C.S., P.S.K. and R.J.H. acknowledge the support of the Engineering and Physical Sciences Research Council (EPSRC) through grants EP/W006006/1...

    work page 2024