The chemical deposition of high-performance zinc oxide (ZnO) thin films is challenging, thus significant efforts have been devoted during the past decades to develop cost-effective, scalable fabrication methods in gas phase. This work demonstrates how ultra-short-pulse laser beam scanning (LBS) can be used to modulate electrical conductivity in ZnO thin films deposited on soda–lime glass by spatial atomic layer deposition (SALD), a high-throughput, low-temperature deposition technique suitable for large-area applications. By systematically optimizing laser parameters, including pulse energy and hatching distance, significant improvements in the electrical performance of 90 nm-thick ZnO films were achieved. The optimization of the laser annealing parameters – 0.21 μJ per pulse energy and a 1 μm hatching distance—yielded ZnO films with an electrical resistivity of (9 ± 2) × 10−2 Ω cm, 3 orders of magnitude lower than as-deposited films. This result suggests that laser post-deposition processing can play an important role in tailoring the properties of ZnO thin films. Excessive laser intensity can compromise structural integrity of the films, however, degrading their electrical transport properties. Notably, the electrical resistance of laser-annealed ZnO films exhibited high sensitivity to oxygen concentration in the surrounding atmosphere, suggesting exciting prospects for application in devices based on transparent oxygen sensors. This study thus positions ultra-short pulsed laser annealing as a versatile post-deposition method for fine-tuning the properties of ZnO thin films, enabling their use in advanced optoelectronic and gas-sensing technologies, particularly on temperature-sensitive substrates., The authors gratefully acknowledge the financial support from EU project SPRINT (H2020-FETOPEN 801464), Spanish projects PID2020-113034RB-I00 (funded by MCIN/AEI/10.13039/501100011033) and PID2023-146041OB-C21 (funded by MICIU/AEI/10.13039/501100011033 and ERDF/EU) and from Gobierno de Aragón (research group T54_23R). The authors would like to acknowledge the use of “Servicio General de Apoyo a la Investigación (SAI)” and the Spanish National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas (LMA)” at the University of Zaragoza. A. Frechilla and J. Frechilla acknowledge support from Gobierno de Aragón via predoctoral contracts., Peer reviewed

The Conductor on Round Core (CORC) and Twisted Stacked-Tape Conductor (TSTC) are among the most promising architectures for high-temperature superconducting (HTS) cables due to their high current-carrying capabilities, essential for future fusion and high voltage -high current- power applications. While CORC designs offer mechanical robustness, their larger cross-sections can lead to spatial inefficiencies, whereas TSTC cables are more compact but limited in transport current. To bridge these trade-offs, a CORC–TSTC hybrid cable has been recently proposed by Korean researchers, though its electromagnetic performance remains largely unverified. In this work, we present a comprehensive three-dimensional electromagnetic study to validate the experimentally measured AC losses of such hybrid cables, using SuNAM Co. Ltd. GdBCO HTS tapes. Our model captures the full current dynamics on the surface and within the superconducting layers, overcoming the limitations of reduced-order gauge (2D) methods. The hybrid cable configurations considered consist of a six-tape CORC outer layer enclosing a TSTC core with one to four stacked tapes. The model incorporates magneto-angular anisotropy in the critical current density, informed by experimental data, to ensure accurate benchmarking. To contextualize the hybrid design’s performance, we also simulate two reference geometries: a single-layer and a double-layer CORC cable, as well as a ten-tape TSTC conductor. Results show that the hybrid configuration offers a compelling balance, combining low AC losses with compact geometry and structural flexibility., This work was supported in part by U.K. Research and Innovation (UKRI), Engineering and Physical Sciences Research Council (EPSRC), led by Harold S. Ruiz under Grant EP/S025707/1; and in part by European Cooperation in Science and Technology through European Cooperation in Science and Technology (COST) Action (Hi-SCALE, https://www.cost.eu/actions/CA19108/ and https://hi-scale.eu/) under Grant CA19108. The work of Hasan N. H. Al-Ssalih was supported by Iraq’s Higher Committee for Education Development (HCED). The work of Matthew Clegg was supported by the University of Leicester and the EPSRC Doctoral Training Program under Grant EP/2438289. The work of Antonio BadÍa-Majós was supported in part by Ministerio de Ciencia, Innovación y Universidades (MICIU) and the Agencia Estatal de Investigación (AEI) under Grant MICIU/AEI/10.13039/501100011033, and the European Regional Development Fund (ERDF) under Project PID2023-146041OB-C21, and in part by Gobierno de Aragón under Grant T54-23R., Peer reviewed

The ability to fabricate anisotropic superconducting layers à la carte is desired in technologies such as fluxon screening or removal in field-resilient devices, flux lensing in ultra-sensitive sensors, or in templates for imprinting magnetic structures in hybrid magnetic/superconducting multilayers. In this work, laser processing is qualified as an enabling technology in the controllable fabrication of superconducting metasurfaces. Niobium thin films exposed to femtosecond ultraviolet laser pulses exhibit significant changes in their superconducting properties, directly connected with the observed surface topography, crystallite geometry, and lattice parameter modifications. On the mesoscopic scale, quasi-parallel periodic ripple structures (about 260 nm of spatial period) gradually form on the film surface by progressively increasing the laser energy per pulse, Ep. This gives way to a stepwise increase of the critical current anisotropy and magnetic flux channeling effects along the ripples. As demonstrated in our resistive and inductive measurements, these superstructures determine the electromagnetic response of the superconducting material. Time-dependent Ginzburg–Landau simulations corroborate the topographical origin of the customized anisotropy. Pulsed laser processing is promoted as a flexible, one-step, and scalable lithography-free technique for versatile surface functionalization in microelectronic superconducting technology., This publication is part of the projects PID2020-113034RB-I00 (funded by MCIN/AEI/ 10.13039/501100011033), PID2023-146041OB-C21 (funded by MICIU/AEI/10.13039/501100011033 and ERDF/EU), and T54-23R (funded by Gobierno de Aragón, Spain). J.F. acknowledges support from Gobierno de Aragón through predoctoral contracts. N.L. acknowledges the support from FRS-FNRS (Research Fellowships FRIA). The work of E.F. has been financially supported by the FWO and F.R.S.-FNRS under the Excellence of Science (EOS) Project No. O.0028.22. The authors would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI (Universidad de Zaragoza) and the Spanish National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas (LMA)” at “Universidad de Zaragoza”. The work of L.R.C. and M.V.M. was sponsored by the Army Research Office, USA and was accomplished under Grant Number W911NF-24-1-0145. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Office or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. The collaboration in this work has been fostered by the EU-COST Action CA21144 SUPERQUMAP., Peer reviewed

Scalable, cost-effective methods for processing transparent electrodes at the microscale are pivotal to advancing in electrochemistry, optoelectronics, microfluidics, and energy harvesting. In these fields, the precise fabrication of micrometric circuits and patterns plays a critical role in determining device performance, material compatibility, and integration with added-value substrates. In this context, Laser Subtractive Manufacturing stands out as a suitable microfabrication technique for its adaptability to diverse materials and complex configurations, as well as its straightforward scalability, affordability, and eco-friendly nature. However, a challenge in micromachining metals and metal oxides is the inherent formation of Laser-Induced Periodic Surface Structures (LIPSS), which can significantly impair electrical conductivity, particularly when circuit dimensions fall within the micrometer range. Herein, we investigate the micromachining of electrical microcircuits using ultrashort pulse laser systems applied to transparent indium tin oxide (ITO) thin films. We analyze the formation of LIPSS at the edges of the micromachined regions associated with the Gaussian distribution of the energy within the laser spot, and the impact of these structures on the electrical properties of the circuits. Thus, we systematically evaluate the influence of LIPSS orientation and periodicity by fabricating various circuit patterns using femtosecond lasers at green (515 nm) and ultraviolet (UV) (343 nm) wavelengths. A correlation between electrical resistivity measurements and microstructure analysis, as determined by field emission scanning electron and transmission electron microscopy, reveals distinct effects of the formed nanostructures depending on the laser source and its polarization. For the green wavelength, the edge side regions where LIPSS are oriented perpendicular to the ITO track exhibit a resistance higher by a factor just above two compared to those where LIPSS are parallel. Additionally, UV laser processing results in a pronounced reduction of ITO thickness at the boundary between the LIPSS region and the substrate. The mechanisms for the formation of LIPSS with both wavelengths are also discussed. Furthermore, we have determined that in narrow conductive tracks with a width ranging from 6 to 8 µm, the impact of LIPSS is particularly significant because the LIPSS structured region occupies a dominant fraction of the total width., The authors are grateful for funding from the European Commission EU H2020 program under grant agreement 899352 (FETOPEN-01-2018-2019-2020 – SOUNDofICE), from the Spanish research projects PID2020-113034RB-I00 (funded by MCIN/AEI/ 10.13039/501100011033), PID2023-146041OB-C21 (funded by MICIU/AEI/10.13039/501100011033 and ERDF/EU) and TED2021-130916B-I00 (funded by MICIU/AEI/10.13039/501100011033, ERDF (FEDER) A way of making Europe, Fondos Nextgeneration EU and Plan de Recuperación, Transformación y Resiliencia) and from the Government of Aragón (Research Group T54_23R). Authors also thank the use of Servicio General de Apoyo a la Investigación – SAI and the Spanish National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas (LMA)” at Universidad de Zaragoza and Servicio de Microscopía Electrónica de Barrido de Alta Resolución at Universidad Pablo de Olavide., Peer reviewed

This review paper delves into the concept of critical current density (Jc) in high-temperature superconductors (HTS) across macroscopic, mesoscopic, and microscopic perspectives. Through this exploration, a comprehensive range of connections is unveiled aiming to foster advancements in the physics, materials science, and the engineering of applied superconductors. Beginning with the macroscopic interpretation of
as a central material law, the review traces its development from C.P. Bean’s foundational work to modern extensions. Mesoscopic challenges in understanding vortex dynamics and their coherence with thermodynamic anisotropy regimes are addressed, underscoring the importance of understanding the limitations and corrections implicit in the macroscopic measurement of Jc, linked with mesoscopic phenomena such as irradiation effects, defect manipulation, and vortex interactions. The transition to supercritical current densities is also discussed, detailing the superconductor behavior beyond critical thresholds with a focus on flux-flow instability regimes relevant to fault current limiters and fusion energy magnets. Enhancing Jc through tailored material microstructures, engineered pinning centers, grain boundary manipulation, and controlled doping is explored, along with radiation techniques and their impact on large-scale energy systems. Emphasizing the critical role of Jc, this review focuses on its physical optimization and engineering manipulation, highlighting its significance across diverse sectors., This review paper is result of the international and multidisciplinary collaboration funded by the European Cooperation in Science and Technology (COST) action CA19108: High-Temperature Superconductivity for Accelerating the Energy Transition, https://www.cost.eu/actions/CA19108/.
All authors thank the COST action for enabling funds for the discussion and publication of this paper. Additionally, HSR’s work was supported by the UK Research and Innovation, Engineering and Physical Sciences Research Council (EPSRC), Grant Refs. EP/S025707/1 and EP/2438289. JH acknowledges support by the German Research Foundation (DFG), grant number HA 6407/4-1. LG and DT acknowledge the support by the Italian Ministry of Education, University, and Research (Project PRIN HIBiSCUS, Grant No. 201785KWLE) and by the Istituto Nazionale di Fisica Nucleare (Experiment SAMARA). DT acknowledges the support by the Ministry of Education, Universities and Research “Programma Operativo Nazionale (PON) Ricerca e Innovazione 2014–2020”. OD acknowledges support by the Austrian Science Fund (FWF), project I6079-N, and by the German Research Foundation (DFG) under Germany’s Excellence Strategy, project EXC-2123 QuantumFrontiers – 390837967. WL acknowledges support by the Austrian Science Fund (FWF), project I4865-N. GG acknowledges support by the Italian Ministry of Education, University, and Research, PON Research and Competitiveness 2007–2013, under grant agreement PON NAFASSY (PONa3-00007). AC, PB and AMI acknowledge the support of the European Regional Development Fund, Operational Program Competitiveness, project POC 28/2016, and the support of Romanian Ministry of Research , Innovation and Digitization through Programs PC2-PN23080202 and 35PFE/2021. RW acknowledges funding support from the Heidelberger Akademie der Wissenschaften through its WIN initiative (8. Teilprogramm). BB acknowledges funding support from the INERCOM platform at LUT University and computational resources from the CSC-IT Center for Science, Finland. BB is also grateful for useful discussions with Dr. Tiina Salmi (Tampere University) and Prof. Petriina Paturi (Turku University). SE acknowledges support from the National Science Foundation DMR-1905909 and DMR-2046925. SGM and JGN acknowledge support from the MSTDI of Republic of Serbia under grant 451-03-68/2022-14/200017. ABM acknowledges the financial support from Spanish MCIN/ AEI/ 10.13039/501100011033 (project PID2020-113034RB-I00), Spanish MCIU/ AEI/ 10.13039/501100011033 (project PID2023-146041OB-C21) and Gobierno de Aragón (research group T54_23R)., Peer reviewed

Focus on Experimental Methods and Best Practices in Superconductivity Research., High-temperature textured YBCO superconductors are considered relevant for applications requiring strong flux pinning, and hence enhanced critical current density and resilient levitation forces, such as maglev systems, magnetic resonance imaging and nuclear magnetic resonance magnets. Improving the performance of YBCO for such applications is commonly achieved by enhancing the flux pinning properties through various mechanisms. In addition, either related to the sample fabrication process or demanded by the final operation conditions, machining these highly brittle samples would be desirable for a number of applications and is a challenging demand. This work reports on the use of ultrashort-pulsed laser irradiation to machine holes into top-seeded melt-growth YBCO samples and how this processing affects their microstructure and superconducting behavior. The x-ray diffraction (XRD) and scanning electron microscopy results demonstrate that ultrashort-pulsed laser machining can create well-defined holes with diminishing microstructural damage. The superconducting properties of the laser-machined samples are essentially preserved, even compatible with the enhancement in the critical current density and levitation force properties. These findings demonstrate the potential of ultrashort-pulsed lasers as a viable tool for machining textured YBCO products and enhancing their performance without degrading their functional properties. This method paves the way towards the generation of artificial defects, machining and shaping of high Tc superconductor ceramics into precisely well-defined complex geometries relevant for power applications., The authors gratefully acknowledge the financial support provided by Ankara University Scientific Research Projects (BAP) Under Project No FDK-2024-3472. The authors also acknowledge the support of COST Action CA19108. One of the co-authors, PhD student Fatima Almokdad, is grateful to TÜBİTAK for the support Under The Project ID 123N624. The experimental measurements and sample machining were carried out with the support of Recep Tayyip Erdoğan University and Spanish projects PID2020-113034RB-I00 (MCIN/AEI/10.13039/ 501100011033), PID2023-146041OB-C21 (MICIU/AEI/10.13039/501100011033 and ERDF/ EU), and T54-23R (Gobierno de Aragón)., Peer reviewed

Laser nitriding is a versatile approach for tailoring the surface properties of metals. To date, its effect on the superconducting response of niobium nitrides remains largely unexplored. In this study, the nitriding of niobium by laser irradiation under controlled nitrogen atmospheres up to 2.50 bar using a nanosecond pulsed laser (λ = 1064 nm) was investigated. Niobium sheets were processed over a wide range of laser conditions, including pulse widths (20–200 ns), repetition frequencies (175–1000 kHz) and scanning speeds (15–250 mm/s). By independently tuning the nitrogen pressure, two-dimensional accumulated fluence (F2D) and laser irradiance, a laser processing map for the formation of β-Nb2N (hexagonal) and γ-Nb4N3±x (tetragonal) phases was established. The phase, microstructural and superconducting properties were characterized using X-ray diffraction, scanning electron microscopy, electron backscatter diffraction and SQUID magnetometry. The γ-phase forms in the near-surface layer through melting when F2D exceeds a threshold (> 50 kJ/cm2 at 2.50 bar). Beneath this layer, a β-layer was observed, followed by embedded β-grains in the Nb matrix, whose size decreases with depth, indicating thermal gradients and a diffusion-controlled growth mechanism. When the γ-phase becomes predominant, the superconducting critical temperature increases to Tc ≈ 15 K, accompanied by magnetic irreversibility. Lower F2D conditions (≈ 7.5 kJ/cm2 at 1.50–2.50 bar) promote a uniform β-Nb2N layer composed of submicron-sized grains, yielding a fourfold enhancement in surface microhardness. These findings establish the first systematic correlation between the laser nitriding parameters and the superconducting properties of Nb–N layers., This publication is part of the projects PID2023–146041OB-C21 (funded by MICIU/AEI/10.13039/501100011033 and ERDF/EU) and T54–23R (funded by the Gobierno de Aragón). J. Frechilla acknowledges the support from the Gobierno de Aragón through predoctoral contracts. The authors would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI (Universidad de Zaragoza) and the Spanish National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas (LMA)” at “Universidad de Zaragoza”., Peer reviewed

This review paper delves into the concept of critical current density in high-temperature superconductors (HTS) across macroscopic, mesoscopic, and microscopic perspectives. Through this exploration, a comprehensive range of connections is unveiled aiming to foster advancements in the physics, materials science, and the engineering of applied superconductors. Beginning with the macroscopic interpretation of as a central material law, the review traces its development from C.P. Bean’s foundational work to modern extensions. Mesoscopic challenges in understanding vortex dynamics and their coherence with thermodynamic anisotropy regimes are addressed, underscoring the importance of understanding the limitations and corrections implicit in the macroscopic measurement of , linked with mesoscopic phenomena such as irradiation effects, defect manipulation, and vortex interactions. The transition to supercritical current densities is also discussed, detailing the superconductor behavior beyond critical thresholds with a focus on flux-flow instability regimes relevant to fault current limiters and fusion energy magnets. Enhancing through tailored material microstructures, engineered pinning centers, grain boundary manipulation, and controlled doping is explored, along with radiation techniques and their impact on large-scale energy systems. Emphasizing the critical role of , this review focuses on its physical optimization and engineering manipulation, highlighting its significance across diverse sectors.

The chemical deposition of high-performance zinc oxide (ZnO) thin films is challenging, thus significant efforts have been devoted during the past decades to develop cost-effective, scalable fabrication methods in gas phase. This work demonstrates how ultra-short-pulse laser beam scanning (LBS) can be used to modulate electrical conductivity in ZnO thin films deposited on soda–lime glass by spatial atomic layer deposition (SALD), a high-throughput, low-temperature deposition technique suitable for large-area applications. By systematically optimizing laser parameters, including pulse energy and hatching distance, significant improvements in the electrical performance of 90 nm-thick ZnO films were achieved. The optimization of the laser annealing parameters – 0.21 μJ per pulse energy and a 1 μm hatching distance—yielded ZnO films with an electrical resistivity of (9 ± 2) × 10−2 Ω cm, 3 orders of magnitude lower than as-deposited films. This result suggests that laser post-deposition processing can play an important role in tailoring the properties of ZnO thin films. Excessive laser intensity can compromise structural integrity of the films, however, degrading their electrical transport properties. Notably, the electrical resistance of laser-annealed ZnO films exhibited high sensitivity to oxygen concentration in the surrounding atmosphere, suggesting exciting prospects for application in devices based on transparent oxygen sensors. This study thus positions ultra-short pulsed laser annealing as a versatile post-deposition method for fine-tuning the properties of ZnO thin films, enabling their use in advanced optoelectronic and gas-sensing technologies, particularly on temperature-sensitive substrates.

The Conductor on Round Core (CORC) and Twisted Stacked-Tape Conductor (TSTC) are among the most promising architectures for high-temperature superconducting (HTS) cables due to their high current-carrying capabilities, essential for future fusion and high voltage -high current- power applications. While CORC designs offer mechanical robustness, their larger cross-sections can lead to spatial inefficiencies, whereas TSTC cables are more compact but limited in transport current. To bridge these trade-offs, a CORC–TSTC hybrid cable has been recently proposed by Korean researchers, though its electromagnetic performance remains largely unverified. In this work, we present a comprehensive three-dimensional electromagnetic study to validate the experimentally measured AC losses of such hybrid cables, using SuNAM Co. Ltd. GdBCO HTS tapes. Our model captures the full current dynamics on the surface and within the superconducting layers, overcoming the limitations of reduced-order gauge (2D) methods. The hybrid cable configurations considered consist of a six-tape CORC outer layer enclosing a TSTC core with one to four stacked tapes. The model incorporates magneto-angular anisotropy in the critical current density, informed by experimental data, to ensure accurate benchmarking. To contextualize the hybrid design’s performance, we also simulate two reference geometries: a single-layer and a double-layer CORC cable, as well as a ten-tape TSTC conductor. Results show that the hybrid configuration offers a compelling balance, combining low AC losses with compact geometry and structural flexibility.

Scalable, cost-effective methods for processing transparent electrodes at the microscale are pivotal to advancing in electrochemistry, optoelectronics, microfluidics, and energy harvesting. In these fields, the precise fabrication of micrometric circuits and patterns plays a critical role in determining device performance, material compatibility, and integration with added-value substrates. In this context, Laser Subtractive Manufacturing stands out as a suitable microfabrication technique for its adaptability to diverse materials and complex configurations, as well as its straightforward scalability, affordability, and eco-friendly nature. However, a challenge in micromachining metals and metal oxides is the inherent formation of Laser-Induced Periodic Surface Structures (LIPSS), which
can significantly impair electrical conductivity, particularly when circuit dimensions fall within the micrometer range. Herein, we investigate the micromachining of electrical microcircuits using ultrashort pulse laser systems applied to transparent indium tin oxide (ITO) thin films. We analyze the formation of LIPSS at the edges of the micromachined regions associated with the Gaussian distribution of the energy within the laser spot, and the impact of these structures on the electrical properties of the circuits. Thus, we systematically evaluate the influence of LIPSS orientation and periodicity by fabricating various circuit patterns using femtosecond lasers at green (515 nm) and ultraviolet (UV) (343 nm) wavelengths. A correlation between electrical resistivity measurements and microstructure analysis, as determined by field emission scanning electron and transmission electron microscopy, reveals distinct effects of the formed nanostructures depending on the laser source and its polarization. For the green wavelength, the edge side regions where LIPSS are oriented perpendicular to the ITO track exhibit a resistance higher by a factor just above two compared to those where LIPSS are parallel. Additionally, UV laser processing results in a pronounced reduction of ITO thickness at the boundary between the LIPSS region and the substrate. The mechanisms for the formation of LIPSS with both wavelengths are also discussed. Furthermore, we have determined that in narrow conductive tracks with a width ranging from 6 to 8 µm, the impact of LIPSS is particularly significant because the LIPSS structured region occupies a dominant fraction of the total width.

High-temperature textured YBCO superconductors are considered relevant for applications requiring strong flux pinning, and hence enhanced critical current density and resilient levitation forces, such as maglev systems, magnetic resonance imaging and nuclear magnetic resonance magnets. Improving the performance of YBCO for such applications is commonly achieved by enhancing the flux pinning properties through various mechanisms. In addition, either related to the sample fabrication process or demanded by the final operation conditions, machining these highly brittle samples would be desirable for a number of applications and is a challenging demand. This work reports on the use of ultrashort-pulsed laser irradiation to machine holes into top-seeded melt-growth YBCO samples and how this processing affects their microstructure and superconducting behavior. The x-ray diffraction (XRD) and scanning electron microscopy results demonstrate that ultrashort-pulsed laser machining can create well-defined holes with diminishing microstructural damage. The superconducting properties of the laser-machined samples are essentially preserved, even compatible with the enhancement in the critical current density and levitation force properties. These findings demonstrate the potential of ultrashort-pulsed lasers as a viable tool for machining textured YBCO products and enhancing their performance without degrading their functional properties. This method paves the way towards the generation of artificial defects, machining and shaping of high Tc superconductor ceramics into precisely well-defined complex geometries relevant for power applications.

Laser nitriding is a versatile approach for tailoring the surface properties of metals. To date, its effect on the superconducting response of niobium nitrides remains largely unexplored. In this study, the nitriding of niobium by laser irradiation under controlled nitrogen atmospheres up to 2.50 bar using a nanosecond pulsed laser (λ = 1064 nm) was investigated. Niobium sheets were processed over a wide range of laser conditions, including pulse widths (20–200 ns), repetition frequencies (175–1000 kHz) and scanning speeds (15–250 mm/s). By independently tuning the nitrogen pressure, two-dimensional accumulated fluence (F2D) and laser irradiance, a laser processing map for the formation of β-Nb2N (hexagonal) and γ-Nb4N3±x (tetragonal) phases was established. The phase, microstructural and superconducting properties were characterized using X-ray diffraction, scanning electron microscopy, electron backscatter diffraction and SQUID magnetometry. The γ-phase forms in the near-surface layer through melting when F2D exceeds a threshold (> 50 kJ/cm2 at 2.50 bar). Beneath this layer, a β-layer was observed, followed by embedded β-grains in the Nb matrix, whose size decreases with depth, indicating thermal gradients and a diffusion-controlled growth mechanism. When the γ-phase becomes predominant, the superconducting critical temperature increases to Tc ≈ 15 K, accompanied by magnetic irreversibility. Lower F2D conditions (≈ 7.5 kJ/cm2 at 1.50–2.50 bar) promote a uniform β-Nb2N layer composed of submicron-sized grains, yielding a fourfold enhancement in surface microhardness. These findings establish the first systematic correlation between the laser nitriding parameters and the superconducting properties of Nb–N layers.

High-current superconducting cables are emerging as key enablers for next-generation power transmission systems; however, their deployment is often limited by transport AC losses. Hybrid superconducting cables combining Conductor-on-Round-Core (CORC) and Twisted Stacked-Tape Conductor (TSTC) architectures have recently been proposed as a promising route toward high-current-capacity power cables and compact form factors. However, their electrodynamic response under transport current operation remains poorly understood, particularly regarding how current feeding conditions govern internal current redistribution. Here, we employ a three-dimensional electromagnetic model, previously validated against magnetization experiments in equivalent cables, to investigate the influence of the current feeding scheme on the electrodynamic behaviour of hybrid CORC–TSTC cables under self-field conditions. By comparing configurations in which the total current is either injected through a common connection between the CORC and TSTC conductors (non-insulated feeding) or supplied independently to each conductor (insulated feeding), we show that electrical coupling in non-insulated designs leads to strong current redistribution, inducing pronounced waveform distortion and elevated AC losses once the CORC layers approach magnetic saturation. In contrast, independent current feeding suppresses inter-conductor current exchange, stabilizes the current waveforms, and exhibits an outstanding reduction in transport AC losses of up to 90% at practical operating currents, compared with conventional feeding schemes. These findings reveal the central role of the current feeding scheme in governing the internal electrodynamics and energy dissipation of hybrid superconducting cables, and identify the electrical decoupling of the constituent conductors at the feeding point as a simple and scalable route toward ultra-efficient hybrid superconducting power cables.