Structural Engineering of La3-xBixNi2O7 Nanofibers via Solution Blow Spinning for Advanced Superconductivity

Davi G. M. Santos¹, Matheus P. Brambilla¹, Alfonso Pulgar¹, Maycon Motta², Rafael Zadorosny¹

¹São Paulo State University (Unesp), School of Engineering, Campus Ilha Solteira - Physics and Chemistry Department
²Federal University of São Carlos (UFSCar), São Carlos, SP (Brazil) - Department of Physics

Abstract
The discovery of high-temperature superconductivity in Ruddlesden-Popper nickelates under high pressure has established La3Ni2O7 as a critical system for understanding unconventional pairing mechanisms [1]. To address synthesis challenges such as phase purity and oxygen non-stoichiometry, this study utilizes Solution Blow Spinning (SBS) combined with a "one-pot" chemical route to produce Bismuth-doped nickelate nanofibers [2]. The partial substitution of Lanthanum by Bismuth was found to modulate metal-to-insulator transitions, highlighting that the structural stability of these layered perovskites is highly sensitive to atomic distortions [3]. Experimental results demonstrated that the use of PVP as a stabilizing agent and optimized thermal treatments at 600°C and 1150°C successfully yielded homogeneous fibers with high surface area and controlled porosity [2,4]. SEM and XRD analyses confirmed the formation of the desired ceramic phases and dense structures, providing an efficient platform for investigating the physical properties and increasing the superconducting volume fraction in nanostructured nickelates [4].

Acknowledgements:
We acknowledge the support of the INCT project Advanced Quantum Materials, involving the Brazilian agencies CNPq (Proc. 408766/2024-7), FAPESP (Proc. 2025/27091-3), CAPES, and CNPq (grant 302786/2025-2).

References
[1] Wang, Yuxin, et al. "Recent progress in nickelate superconductors." National Science Review 12.10 (2025): nwaf373.
[2] Rotta, Maycon, et al. "One-pot-like facile synthesis of YBa2Cu3O7-δ superconducting ceramic: Using PVP to obtain a precursor solution in two steps." Materials Chemistry and Physics 243 (2020): 122607.
[3] Zhang, Hao, et al. "Continuously adjustable metal to insulator transitions within high temperature range for La3-xBixNi2O7 layered perovskite nickelates." Scripta Materialia 264 (2025): 116720.
[4] Adachi, Yoshinobu, et al. "Preparation of pure and fully dense lanthanum nickelates Lan+ 1NinO3n+ 1 (n= 2, 3,∞) by post‐sintering oxidation process." Journal of the American Ceramic Society 102.12 (2019): 7077-7088.