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arxiv: 2604.15981 · v1 · submitted 2026-04-17 · ❄️ cond-mat.mtrl-sci · cond-mat.supr-con

Laser induced surface nitriding of niobium: phase evolution and superconducting behaviour

J. Frechilla , A. Frechilla , G.F. de la Fuente , A. Larrea , L.A. Angurel , E. Mart\'inez This is my paper

Pith reviewed 2026-05-10 08:44 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci cond-mat.supr-con
keywords betalaserniobiumnitridingphasesuperconductingsurfaceformation
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The pith

Laser nitriding of niobium produces controllable beta-Nb2N and gamma-Nb4N3 phases that deliver fourfold surface hardness gains at low fluence and raise superconducting critical temperature to 15 K when gamma phase dominates.

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

Laser nitriding uses a powerful laser beam to heat the surface of niobium metal while it sits in a chamber filled with nitrogen gas. The laser energy causes nitrogen atoms to react with the niobium, forming thin layers of niobium nitride compounds right on the surface. By changing the gas pressure, how much laser energy hits the surface over time, and the intensity of the laser pulses, the researchers created a map showing which conditions produce different types of nitride layers. At higher energy levels, a nitrogen-rich phase called gamma-Nb4N3 forms near the top surface after the material melts. Below that, a different phase called beta-Nb2N appears, and even deeper, small grains of beta phase sit inside the original niobium metal. The size of these grains gets smaller farther from the surface, pointing to how heat and atoms moving around create the layers. When the gamma phase covers most of the surface, the material starts to show superconductivity at temperatures up to 15 Kelvin, which is higher than usual for some niobium compounds, along with stronger resistance to magnetic fields. At lower energy settings, a smooth layer of tiny beta phase grains makes the surface about four times harder to scratch or dent. This work shows how laser processing can be tuned to create custom surface layers that combine good mechanical strength with useful superconducting behavior.

Core claim

When the γ-phase becomes predominant, a significant increase in the superconducting critical temperature is observed, up to Tc ≈ 15 K, and magnetic irreversibility. For low F2D values (≈ 7.5 kJ/cm² at 1.50-2.50 bar), the formation of a uniform nitride layer composed of sub-micron-sized β-Nb2N grains results in a ca. fourfold enhancement in surface microhardness.

Load-bearing premise

The assumption that XRD patterns alone unambiguously identify the β-Nb2N and γ-Nb4N3±x phases and that the observed grain-size gradient is caused solely by thermal gradients and diffusion without contributions from plasma chemistry or rapid quenching effects.

Figures

Figures reproduced from arXiv: 2604.15981 by A. Frechilla, A. Larrea, E. Mart\'inez, G.F. de la Fuente, J. Frechilla, L.A. Angurel.

Figure 3
Figure 3. Figure 3: FESEM (AsB) images of the polished cross-sections of laser-nitrided niobium samples processed at different conditions (see table 1), taken at two different magnifications. Note that images of sample S3 are presented at a higher magnification to allow clearer visualization of the nitride layer. A detailed analysis of the distribution of the laser-generated nitrides was performed by EBSD experiments on polis… view at source ↗
Figure 4
Figure 4. Figure 4: displays the collected maps for sample S6, which was processed with F2D = 113 kJ/cm2 . The Phase-map shows that the nitride layer in this sample is composed predominantly of β-Nb2N phase (in red colour). The β-grains form an almost continuous layer near the surface and are also embedded within the Nb (yellow) matrix. On the surface, a submicron-thick, discontinuous γ-Nb4N3±x (green) layer indicates local s… view at source ↗
Figure 5
Figure 5. Figure 5: EBSD maps –FSE, Phase and IPF-Y, from top to bottom– of polished cross-sections of samples i) S7 and ii) S9. EBSD analysis confirms the absence of the cubic δ-NbN1-x phase in all these samples. As already mentioned in section 3.1, this is indicative of nitrogen deficiency at the surface for the temperature/pressure conditions used in the present work [41]. The formation of the -phase at temperatures near … view at source ↗
Figure 6
Figure 6. Figure 6: shows the Vickers microhardness experiments performed in different samples to analyse the changes in the mechanical properties produced by the generated nitride phases. The curves display the variation of hardness with indentation depth, thereby probing sequentially from the outermost surface to the deeper regions, with penetration depths of approximately 3–25 µm. This study was mainly focused on the sampl… view at source ↗
Figure 7
Figure 7. Figure 7: Superconducting properties measured on 2a x 2a processed samples at temperatures higher than Tc,Nb: A) AC susceptibility (in-phase component). B) ZFC–FC magnetization measurements (open-full symbols), plotted as M·d ≡ m/(2a) 2 , under an applied field of 2 mT (see text). C) Magnetization hysteresis loops, M(μ0H)·d , measured at 10 K and D) corresponding ΔM/ΔMmax calculated from C). The discontinuous lines … view at source ↗
Figure 8
Figure 8. Figure 8: displays the magnetization hysteresis loops at different temperatures (T > Tc,Nb) for the sample that exhibits the best results, S10. The corresponding ΔM/ΔMmax curves, normalized to the maximum value at 9.5 K, are also displayed. For all temperatures, an almost exponential decay of ΔM/ΔMmax with applied field is observed, showing a decreasing trend with different slopes in distinct field regions. The deca… view at source ↗
read the original abstract

Laser nitriding represents a versatile approach for tailoring the surface properties of metals. Up to now, its effect on the superconducting response of niobium nitrides remains largely unexplored. In this work, the nitriding process of niobium by laser irradiation under a controlled nitrogen atmosphere up to 2.50 bar, using a nanosecond pulsed laser with wavelength of 1064 nm has been investigated. By independently tuning the nitrogen pressure, the two-dimensional accumulated fluence ($F_{2D}$) and the laser irradiance, a laser-processing map for the formation of either a combination of $\beta$-Nb$_2$N (hexagonal) and $\gamma$-Nb$_4$N$_{3\pm x}$ (tetragonal) phases or only the $\beta$-phase has been established. Systematic analysis by X-ray diffraction, scanning electron microscopy and electron backscatter diffraction revealed that the nitrogen-rich $\gamma$-phase forms in the near-surface layer through melting when $F_{2D}$ exceeds a certain value ($> 50 \,\mathrm{kJ/cm^2}$ at 2.50 bar). A $\beta$-layer is observed underneath, and further inside, there is a band of embedded $\beta$-grains in the Nb matrix. Their size gradually decreases with increasing distance to surface, suggesting thermal gradients and a diffusion formation mechanism. When the $\gamma$-phase becomes predominant, a significant increase in the superconducting critical temperature is observed, up to $T_c \approx 15\,\mathrm{K}$, and magnetic irreversibility. For low $F_{2D}$ values ($\approx 7.5 \,\mathrm{kJ/cm^2}$ at 1.50-2.50 bar), the formation of a uniform nitride layer composed of sub-micron-sized $\beta$-Nb$_2$N grains results in a ca. fourfold enhancement in surface microhardness. These findings provide fundamental insights into laser-induced nitriding of niobium to engineer mechanically robust and superconducting Nb-N layers.

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

3 major / 2 minor

Summary. The manuscript reports an experimental investigation of laser-induced nitriding of niobium under controlled nitrogen pressures (up to 2.5 bar) using a 1064 nm nanosecond pulsed laser. By varying nitrogen pressure, two-dimensional accumulated fluence F_{2D}, and irradiance, the authors establish a processing map showing formation of β-Nb₂N (hexagonal) alone or in combination with γ-Nb₄N_{3±x} (tetragonal). XRD, SEM, and EBSD characterization indicate that the nitrogen-rich γ-phase forms in the near-surface layer via melting above ~50 kJ/cm² at 2.5 bar, with a β-layer beneath and embedded β-grains deeper in the Nb matrix whose size decreases with depth. When γ-phase predominates, Tc rises to ~15 K with magnetic irreversibility; at low F_{2D} (~7.5 kJ/cm²), a uniform sub-micron β-Nb₂N layer yields ~4× surface microhardness increase.

Significance. If the phase–property correlations are robustly established, the work offers a practical laser-processing route to create Nb-N surface layers combining enhanced superconductivity (Tc up to 15 K) and mechanical hardness, relevant for superconducting RF cavities, coatings, or hybrid devices. The multi-technique tracking of microstructure and the fluence/pressure map constitute useful empirical guidance.

major comments (3)
  1. [Results (XRD and superconductivity subsections)] Results section (XRD analysis and phase-evolution discussion): The assignment of γ-Nb₄N_{3±x} predominance above ~50 kJ/cm² rests on qualitative inspection of XRD peak positions and intensities without Rietveld refinement, quantitative phase fractions, or intensity-ratio calibration. In the Nb-N system, β and γ reflections can overlap or shift with stoichiometry; absent orthogonal confirmation (e.g., XPS N stoichiometry or TEM), the claim that γ-phase predominance directly produces the Tc increase to ~15 K and irreversibility remains unsupported.
  2. [Abstract and superconductivity characterization] Abstract and superconductivity results: No error bars are reported on the Tc values, and the extraction method (onset, midpoint, or zero-resistance criterion) is not specified. These omissions are load-bearing for the central claim of a “significant increase” to Tc ≈ 15 K when γ-phase becomes predominant.
  3. [Discussion] Discussion of microstructure: The grain-size gradient is attributed solely to thermal gradients and diffusion, yet no experimental test or argument excludes contributions from plasma chemistry or rapid-quenching kinetics. This weakens the mechanistic interpretation even if the phase–Tc correlation is addressed.
minor comments (2)
  1. [Methods / Results] The definition and units of F_{2D} are introduced only in the abstract; a clear definition with units should appear in the methods or first results paragraph.
  2. [Figure captions] Figure captions for SEM/EBSD images should explicitly state the fluence, pressure, and depth for each panel to allow direct correlation with the processing map.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the constructive and detailed comments, which have helped us identify areas where the manuscript can be strengthened. We address each major comment below and outline the revisions we will make.

read point-by-point responses

  1. Referee: Results section (XRD analysis and phase-evolution discussion): The assignment of γ-Nb₄N_{3±x} predominance above ~50 kJ/cm² rests on qualitative inspection of XRD peak positions and intensities without Rietveld refinement, quantitative phase fractions, or intensity-ratio calibration. In the Nb-N system, β and γ reflections can overlap or shift with stoichiometry; absent orthogonal confirmation (e.g., XPS N stoichiometry or TEM), the claim that γ-phase predominance directly produces the Tc increase to ~15 K and irreversibility remains unsupported.

    Authors: We agree that Rietveld refinement would provide stronger quantitative support for the phase fractions. In the revised manuscript we will add Rietveld analysis of the XRD patterns to extract phase fractions as a function of fluence and pressure, confirming the transition to γ-Nb₄N_{3±x} predominance above ~50 kJ/cm² at 2.5 bar. We will also include intensity-ratio calibration where possible. While XPS and TEM were not performed in this study, the combination of XRD peak matching, SEM cross-sections showing the near-surface layer, and EBSD phase mapping already provides orthogonal microstructural evidence for the γ-phase location. The Tc increase to ~15 K is observed precisely when the processing map indicates γ predominance; we will rephrase the text to state that the correlation is supported by the fluence threshold rather than claiming direct causation from phase fraction alone. revision: yes

  2. Referee: Abstract and superconductivity results: No error bars are reported on the Tc values, and the extraction method (onset, midpoint, or zero-resistance criterion) is not specified. These omissions are load-bearing for the central claim of a “significant increase” to Tc ≈ 15 K when γ-phase becomes predominant.

    Authors: We accept this criticism. In the revised version we will specify that Tc is determined using the onset criterion (10% of the normal-state resistance drop) and will report error bars derived from repeated measurements on multiple samples. The abstract will be updated accordingly to reflect the revised presentation of the Tc data while retaining the observed increase to approximately 15 K under γ-dominant conditions. revision: yes

  3. Referee: Discussion of microstructure: The grain-size gradient is attributed solely to thermal gradients and diffusion, yet no experimental test or argument excludes contributions from plasma chemistry or rapid-quenching kinetics. This weakens the mechanistic interpretation even if the phase–Tc correlation is addressed.

    Authors: We will expand the discussion to acknowledge that plasma chemistry and rapid-quenching effects cannot be entirely ruled out with the present data. However, the observed monotonic decrease in β-grain size with depth correlates directly with the expected thermal gradient from the laser-melted surface, and the grain-size trend persists across different nitrogen pressures where plasma conditions vary. We will add a brief paragraph noting these alternative mechanisms as possible secondary contributions while maintaining that thermal diffusion remains the dominant explanation supported by the depth-dependent EBSD observations and fluence dependence. revision: partial

Circularity Check

0 steps flagged

No circularity: purely experimental observations without derived predictions or self-referential definitions

full rationale

This is a purely experimental materials-science study. The authors perform laser nitriding under controlled conditions, characterize phases and microstructures via XRD, SEM, and EBSD, and report direct measurements of Tc (up to ~15 K) and microhardness enhancement. No equations, models, fitted parameters, or 'predictions' are presented that reduce by construction to author-defined inputs. Phase identification and property correlations rest on standard empirical techniques and direct observation; the processing map is established from experimental outcomes rather than any self-referential derivation. No load-bearing self-citations or ansatzes appear in the provided text.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

No free parameters or invented entities are introduced. The work rests on two standard domain assumptions in materials science.

axioms (2)
  • domain assumption X-ray diffraction patterns can be used to unambiguously identify β-Nb2N (hexagonal) and γ-Nb4N3±x (tetragonal) phases
    Invoked when the authors assign phases from XRD data without additional verification methods mentioned in the abstract.
  • domain assumption The observed decrease in β-grain size with depth is caused by thermal gradients and diffusion
    Stated as the suggested formation mechanism for the embedded-grain band.

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Reference graph

Works this paper leans on

62 extracted references · 62 canonical work pages

  1. [1]

    Laser Nitriding of Titanium and Its Alloys

    Katayama, S., Matsunawa, A., Morimoto, A., Ishimoto, S., & Arata, Y. (1984). "Laser Nitriding of Titanium and Its Alloys." Proceedings of the 3rd International Congress on Applications of Lasers and Electro-Optics (ICALEO '83), Laser Institute of America (L.I.A.), Vol. 38, pp. 127–134

    work page 1984

  2. [2]

    Aluminum nitriding by laser

    Prescott, G. R., & Cochran, W. C. (1984). "Aluminum nitriding by laser." U.S. Patent No. 4,451,302. Washington, DC: U.S. Patent and Trademark Office. Issued May 29, 1984

    work page 1984

  3. [3]

    Process for surface hardening a piece of steel, and a piece of steel hardened by the process

    Coulon, A. (1995). "Process for surface hardening a piece of steel, and a piece of steel hardened by the process." U.S. Patent No. 5,413,641. Washington, DC: U.S. Patent and Trademark Office. Issued May 9, 1995

    work page 1995

  4. [4]

    Laser nitriding of metals

    Schaaf P. Laser nitriding of metals. Prog Mater Sci 2002; 47: 1–161

    work page 2002

  5. [5]

    Effects of nitriding temperature on microstructures and vacuum tribological properties of plasma-nitrided titanium

    She D, Yue W, Fu Z, et al. Effects of nitriding temperature on microstructures and vacuum tribological properties of plasma-nitrided titanium. Surf Coatings Technol 2015; 264: 32–40

    work page 2015

  6. [6]

    Laser nitriding of titanium surfaces for biomedical applications

    Zeng C, Wen H, Hemmasian Ettefagh A, et al. Laser nitriding of titanium surfaces for biomedical applications. Surf Coatings Technol 2020; 385: 125397

    work page 2020

  7. [7]

    Reactive surface processing by irradiation with excimer laser, Nd:YAG laser, free electron laser and Ti:sapphire laser in nitrogen atmosphere

    Carpene E, Schaaf P, Han M, et al. Reactive surface processing by irradiation with excimer laser, Nd:YAG laser, free electron laser and Ti:sapphire laser in nitrogen atmosphere. Appl Surf Sci 2002; 186: 195–199

    work page 2002

  8. [8]

    Laser nitriding of iron and aluminum

    Carpene E, Schaaf P. Laser nitriding of iron and aluminum. Appl Surf Sci 2002; 186: 100–104

    work page 2002

  9. [9]

    Laser nitridation on Ti-6.5Al-3.5Mo-1.5Zr-0.3Si titanium alloy

    Zong X, Wang H, Li Z, et al. Laser nitridation on Ti-6.5Al-3.5Mo-1.5Zr-0.3Si titanium alloy. Surf Coatings Technol 2020; 386: 125425

    work page 2020

  10. [10]

    Chan CW, Quinn J, Hussain I, et al. A promising laser nitriding method for the design of next generation orthopaedic implants: Cytotoxicity and antibacterial performance of titanium nitride (TiN) wear nano-particles, and enhanced wear properties of laser-nitrided Ti6Al4V surfaces. Surf Coatings Technol 2021; 405: 126714

    work page 2021

  11. [11]

    Microstructural, mechanical, and corrosion properties of plasma-nitrided CoCrFeMnNi high-entropy alloys

    Nishimoto A, Fukube T, Maruyama T. Microstructural, mechanical, and corrosion properties of plasma-nitrided CoCrFeMnNi high-entropy alloys. Surf Coatings Technol 2019; 376: 52–58

    work page 2019

  12. [12]

    Laser nitriding of niobium for application to superconducting radio-frequency accelerator cavities

    Singaravelu S, Klopf J, Krafft G, et al. Laser nitriding of niobium for application to superconducting radio-frequency accelerator cavities. J Vac Sci Technol B Microelectron Nanom Struct 2011; 29: 1803–1808

    work page 2011

  13. [13]

    Nitridation of Nb surface by nanosecond and femtosecond laser pulses

    Farha AH, Ozkendir OM, Koroglu U, et al. Nitridation of Nb surface by nanosecond and femtosecond laser pulses. J Alloys Compd 2015; 618: 685–693

    work page 2015

  14. [14]

    “in-situ” XPS studies of laser induced surface cleaning and nitridation of Ti

    Lahoz R, Espinós JP, de la Fuente GF, González-Elipe AR. “in-situ” XPS studies of laser induced surface cleaning and nitridation of Ti. Surf. Coat. Technol. 2008; 202: 1486.-1492

    work page 2008

  15. [15]

    “in-situ” XPS 19 studies of laser-induced surface nitridation and oxidation of tantalum

    Lahoz R, Espinós JP, Yubero F, González-Elipe AR, de la Fuente GF. “in-situ” XPS 19 studies of laser-induced surface nitridation and oxidation of tantalum. J. Mater. Res. 2015; 30: 2967-2976

    work page 2015

  16. [16]

    Sputter Epitaxy of Transition Metal Nitrides: Advances in Superconductors, Semiconductors, and Ferroelectrics

    Kobayashi A, Maeda T, Akiyama T, et al. Sputter Epitaxy of Transition Metal Nitrides: Advances in Superconductors, Semiconductors, and Ferroelectrics. Phys Status Solidi Appl Mater Sci 2025; 2400896: 1–10

    work page 2025

  17. [17]

    Superconducting properties of high- purity niobium

    Finnemore DK, Stromberg TF, Swenson CA. Superconducting properties of high- purity niobium. Phys Rev 1966; 149: 231–243

    work page 1966

  18. [18]

    Transition temperatures and crystal structures of single- crystal and polycrystalline NbNx films

    Oya GI, Onodera Y. Transition temperatures and crystal structures of single- crystal and polycrystalline NbNx films. J Appl Phys 1974; 45: 1389–1397

    work page 1974

  19. [19]

    Substrate mediated nitridation of niobium into superconducting Nb2N thin films for phase slip study

    Gajar B, Yadav S, Sawle D, et al. Substrate mediated nitridation of niobium into superconducting Nb2N thin films for phase slip study. Sci Rep 2019; 9: 1–11

    work page 2019

  20. [20]

    Discovery of superconductivity in hard hexagonal ϵ- NbN

    Zou Y, Qi X, Zhang C, et al. Discovery of superconductivity in hard hexagonal ϵ- NbN. Sci Rep 2016; 6: 1–9

    work page 2016

  21. [21]

    Study of niobium nitrides for superconducting rf cavities

    Fabbricatore P, Fernandes P, Gualco GC, et al. Study of niobium nitrides for superconducting rf cavities. J Appl Phys 1989; 66: 5944–5949

    work page 1989

  22. [22]

    Preparation of NbN single crystals

    Scheerer B. Preparation of NbN single crystals. J Cryst Growth 1980; 49: 61–66

    work page 1980

  23. [23]

    Unexplored MBE growth mode reveals new properties of superconducting NbN

    Wright J, Chang C, Waters D, et al. Unexplored MBE growth mode reveals new properties of superconducting NbN. Phys Rev Mater 2021; 5: 1–8

    work page 2021

  24. [24]

    Superconducting transition temperatures of r

    Keskar KS, Yamashita T, Onodera Y. Superconducting transition temperatures of r. F. sputtered NbN films. Jpn J Appl Phys 1971; 10: 370–374

    work page 1971

  25. [25]

    Nanomechanical properties of NbN films prepared by pulsed laser deposition using nanoindendation

    Mamun MA, Farha AH, Er AO, et al. Nanomechanical properties of NbN films prepared by pulsed laser deposition using nanoindendation. Appl Surf Sci 2012; 258: 4308–4313

    work page 2012

  26. [26]

    Superconducting NbN thin films for use in superconducting radio frequency cavities

    Leith S, Vogel M, Fan J, et al. Superconducting NbN thin films for use in superconducting radio frequency cavities. Supercond Sci Technol 2021; 34: 5006– 5017

    work page 2021

  27. [27]

    Niobium and niobium-titanium nitrides for rf applications

    Fabbricatore P, Gemme G, Musenich R, et al. Niobium and niobium-titanium nitrides for rf applications. IEEE Trans Appl Supercond 1993; 3: 1761–1764

    work page 1993

  28. [28]

    Niobium Nitride Preparation for Superconducting Single-Photon Detectors

    Luo P, Zhao Y. Niobium Nitride Preparation for Superconducting Single-Photon Detectors. Molecules 2023; 28: 6200–6219

    work page 2023

  29. [29]

    Superconducting niobium nitride: A perspective from processing, microstructure, and superconducting property for single photon detectors

    Cucciniello N, Lee D, Feng HY, et al. Superconducting niobium nitride: A perspective from processing, microstructure, and superconducting property for single photon detectors. J Phys Condens Matter 2022; 34: 4003–4017

    work page 2022

  30. [30]

    Niobium Nitride Nb4N5 as a New High-Performance Electrode Material for Supercapacitors

    Cui H, Zhu G, Liu X, et al. Niobium Nitride Nb4N5 as a New High-Performance Electrode Material for Supercapacitors. Adv Sci 2015; 2: 1–12

    work page 2015

  31. [31]

    Niobium and niobium nitride SQUIDs based on anodized nanobridges made with an atomic force microscope

    Faucher M, Fournier T, Pannetier B, et al. Niobium and niobium nitride SQUIDs based on anodized nanobridges made with an atomic force microscope. Phys C Supercond its Appl 2002; 368: 211–217

    work page 2002

  32. [32]

    NanoSQUIDs based on niobium nitride films

    Russo R, Esposito E, Crescitelli A, et al. NanoSQUIDs based on niobium nitride films. Supercond Sci Technol 2017; 30: 4009–4014. 20

    work page 2017

  33. [33]

    Wafer-level uniformity of atomic-layer- deposited niobium nitride thin films for quantum devices

    Knehr E, Ziegler M, Linzen S, et al. Wafer-level uniformity of atomic-layer- deposited niobium nitride thin films for quantum devices. J Vac Sci Technol A Vacuum, Surfaces, Film 2021; 39: 2401–2407

    work page 2021

  34. [34]

    Niobium zirconium nitride sputter-deposited protective coatings

    Debessai M, Filip P, Aouadi SM. Niobium zirconium nitride sputter-deposited protective coatings. Appl Surf Sci 2004; 236: 63–70

    work page 2004

  35. [35]

    Growth of niobium nitrides by nitrogen-niobium reaction at high temperature

    Musenich R, Fabbricatore P, Gemme G, et al. Growth of niobium nitrides by nitrogen-niobium reaction at high temperature. J Alloys Compd 1994; 209: 319– 328

    work page 1994

  36. [36]

    Formation of niobium nitride by rapid thermal processing

    Angelkort C, Lewalter H, Warbichler P, et al. Formation of niobium nitride by rapid thermal processing. Spectrochim Acta - Part A Mol Biomol Spectrosc 2001; 57: 2077–2089

    work page 2001

  37. [37]

    Synthesis of cubic niobium nitride by reactive diffusion under nitrogen pressure

    Linde A V., Marin-Ayral RM, Granier D, et al. Synthesis of cubic niobium nitride by reactive diffusion under nitrogen pressure. Mater Res Bull 2009; 44: 1025–1030

    work page 2009

  38. [38]

    Effect of pressure on the composition and superconducting Tc value of NbN prepared by combustion synthesis

    Buscaglia V, Caracciolo F, Ferretti M, et al. Effect of pressure on the composition and superconducting Tc value of NbN prepared by combustion synthesis. J Alloys Compd 1998; 266: 201–206

    work page 1998

  39. [39]

    Berger, W

    R. Berger, W. Lengauer, P. Ettmayer. The γ-Nb4N3±x → δ-NbN1-x phase transition. J Alloys Compd 1997; 259: L9–L13

    work page 1997

  40. [40]

    Multiphase reaction diffusion in metal-carbon and transition metal- nitrogen systems

    Lengauer W. Multiphase reaction diffusion in metal-carbon and transition metal- nitrogen systems. J Alloys Compd 1995; 229: 80–92

    work page 1995

  41. [41]

    High-temperature reactive phase formation in the Nb-N system

    Joguet M, Lengauer W, Bohn M, et al. High-temperature reactive phase formation in the Nb-N system. J Alloys Compd 1998; 269: 233–237

    work page 1998

  42. [42]

    High-Tc superconducting NbN films with low particulate density grown at 25 °C using pulsed laser deposition

    Kaul AB, Sands TD, Van Duzer T. High-Tc superconducting NbN films with low particulate density grown at 25 °C using pulsed laser deposition. J Mater Res 2001; 16: 1223–1226

    work page 2001

  43. [43]

    NbN superconducting thin films grown by pulsed laser ablation

    Boffa V, Gambardella U, Marotta V, et al. NbN superconducting thin films grown by pulsed laser ablation. Appl Surf Sci 1996; 106: 361–364

    work page 1996

  44. [44]

    Laser-fluence effects on NbNx thin films fabricated by pulsed laser deposition

    Farha AH, Er AO, Ufuktepe Y, et al. Laser-fluence effects on NbNx thin films fabricated by pulsed laser deposition. Mater Chem Phys 2012; 132: 667–672

    work page 2012

  45. [45]

    Superconducting niobium nitride films deposited by unbalanced magnetron sputtering

    Olaya JJ, Huerta L, Rodil SE, et al. Superconducting niobium nitride films deposited by unbalanced magnetron sputtering. Thin Solid Films 2008; 516: 8768–8773

    work page 2008

  46. [46]

    Niobium nitride thin films deposited by high temperature chemical vapor deposition

    Mercier F, Coindeau S, Lay S, et al. Niobium nitride thin films deposited by high temperature chemical vapor deposition. Surf Coatings Technol 2014; 260: 126– 132

    work page 2014

  47. [47]

    Improved critical temperature of superconducting plasma-enhanced atomic layer deposition of niobium nitride thin films by thermal annealing

    Tian L, Bottala-Gambetta I, Marchetto V, et al. Improved critical temperature of superconducting plasma-enhanced atomic layer deposition of niobium nitride thin films by thermal annealing. Thin Solid Films 2020; 709: 138232

    work page 2020

  48. [48]

    On the kinetics of nitride and diffusion layer growth in niobium plasma nitriding

    Kertscher R, Brunatto SF. On the kinetics of nitride and diffusion layer growth in niobium plasma nitriding. Surf Coatings Technol 2020; 401: 126220

    work page 2020

  49. [49]

    Microstructure and transport properties of Bi-2212 prepared by CO2 laser line scanning

    Lennikov V, Özkurt B, Angurel LA, et al. Microstructure and transport properties of Bi-2212 prepared by CO2 laser line scanning. J Supercond Nov Magn 2013; 26: 21 947–952

    work page 2013

  50. [50]

    Spatially selective crystallization of ferroelectric Hf0.5Zr0.5O2 films induced by sub-nanosecond laser annealing

    Frechilla A, Napari M, Strkalj N, et al. Spatially selective crystallization of ferroelectric Hf0.5Zr0.5O2 films induced by sub-nanosecond laser annealing. Appl Mater Today 2024; 36: 102033

    work page 2024

  51. [51]

    Highly Regular Hexagonally-Arranged Nanostructures on Ni-W Alloy Tapes upon Irradiation with Ultrashort UV Laser Pulses

    Porta-Velilla L, Turan N, Cubero Á, et al. Highly Regular Hexagonally-Arranged Nanostructures on Ni-W Alloy Tapes upon Irradiation with Ultrashort UV Laser Pulses. Nanomaterials 2022; 12: 2380–2402

    work page 2022

  52. [52]

    JCPDS-International Centre for Diffraction Data. 2000

    work page 2000

  53. [53]

    Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

    Höche D, Schikora H, Zutz H, et al. Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation. Appl Phys A Mater Sci Process 2008; 91: 305– 314

    work page 2008

  54. [54]

    The effect of laser scanning strategies on texture, mechanical properties, and site-specific grain orientation in selective laser melted 316L SS

    Marattukalam JJ, Karlsson D, Pacheco V, et al. The effect of laser scanning strategies on texture, mechanical properties, and site-specific grain orientation in selective laser melted 316L SS. Mater Des 2020; 193: 108852

    work page 2020

  55. [55]

    Growth rate effects on thin Bi2Sr2CaCu2O8+δ textured rods

    Angurel LA, Dı́ez JC, Martı́nez E, et al. Growth rate effects on thin Bi2Sr2CaCu2O8+δ textured rods. Phys C Supercond 1998; 302: 39–50

    work page 1998

  56. [56]

    Laser nitriding: Investigations on the model system TiN

    Höche D, Schaaf P. Laser nitriding: Investigations on the model system TiN. A review. Heat Mass Transf und Stoffuebertragung 2011; 47: 519–540

    work page 2011

  57. [57]

    Nanoindentation study of niobium nitride thin films on niobium fabricated by reactive pulsed laser deposition

    Mamun MA Al, Farha AH, Ufuktepe Y, et al. Nanoindentation study of niobium nitride thin films on niobium fabricated by reactive pulsed laser deposition. Appl Surf Sci 2015; 330: 48–55

    work page 2015

  58. [58]

    Structural, electronic, and mechanical properties of niobium nitride prepared by thermal diffusion in nitrogen

    Ufuktepe Y, Farha AH, Kimura SI, et al. Structural, electronic, and mechanical properties of niobium nitride prepared by thermal diffusion in nitrogen. Mater Chem Phys 2013; 141: 393–400

    work page 2013

  59. [59]

    Structure- and composition-tunable superconductivity, band topology, and elastic response of hard binary niobium nitrides Nb2N, Nb4N3 and Nb4N5

    Babu KR, Guo GY. Structure- and composition-tunable superconductivity, band topology, and elastic response of hard binary niobium nitrides Nb2N, Nb4N3 and Nb4N5. Phys Rev B 2023; 108: 1–12

    work page 2023

  60. [60]

    A., Escobar-Rincón, D., Restrepo-Parra, E., & de la Cruz, W

    Garzon-Fontecha, A., Castillo, H. A., Escobar-Rincón, D., Restrepo-Parra, E., & de la Cruz, W. (2019). Correlation Between Stoichiometry of NbxNy Coatings Produced by DC Magnetron Sputtering with Electrical Conductivity and the Hall Coefficient. Coatings 2019; 9: 196

    work page 2019

  61. [61]

    Y., Barmak, K., Rudman, D

    Juang, J. Y., Barmak, K., Rudman, D. A., & van Dover, R. B. Enhancement of the critical current by grain size refinement in Ta-cosputtered NbN thin films. Journal of Applied Physics, 1989; 66: 3136–3143. Supporting information: Laser nitriding of bulk niobium: phase evolution and superconducting behaviour J. Frechilla1, A. Frechilla1, G.F. de la Fuente1, ...

    work page 1989

  62. [62]

    Instituto de Nanociencia y Materiales de Aragón, INMA, CSIC-Universidad de Zaragoza, María de Luna, 3, 50018 Zaragoza, Spain 23 S1. XRD patterns In this supplementary section, the X-ray diffraction (XRD) patterns of the same samples presented in Figure 1 of the main text are shown over an extended angular range (30– 80°). The samples are named as in the m...

    work page