Optimization of Synthesis Parameters and Superconducting Properties of GdFeAsOF

• Published in: IEEE transactions on applied superconductivity 2024-05, Vol.34 (3), p.1-5
• Main Authors: Azam, Mohammad, Manasa, Manasa, Zajarniuk, Tatiana, Stelmakh, Svitlana, Cetner, Tomasz, Morawski, Andrzej, Wi'niewski, Andrzej, Singh, Shiv J.
• Format: Article
• Language: English
• Subjects: 1111 family; Critical current (superconductivity); critical current density; critical transition temperature; Electrons; Fluorine; Gadolinium; Heating systems; Iron; Iron-based superconductor; Lattices; Magnetic measurement; Optimization; Parameters; polycrystalline samples; Powders; Pressure; Rare earth elements; Superconducting transition temperature; Superconductivity; Superconductors; Synthesis; Temperature; Transition temperature
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2023.3341858

RE FeAsO ( RE 1111; RE : rare earth) belongs to the 1111 family of iron-based superconductors (FBS), which illustrates the enhancement of the superconducting transition ( T c ) with smaller radii of RE . However, the synthesis of the 1111 phase with a heavy rare-earth is always challenging. In this paper, we report the optimization of the growth and superconducting properties of F-doped GdFeAsO 1- x F x bulks by preparing the samples in a wide temperature range (700-1100 °C) at ambient pressure. The optimized synthesis parameters are concluded based on structural, microstructural, transport, and magnetic measurements. These findings suggest that the optimal conditions for preparing F-doped Gd1111 bulks involve a two-step process at 900 °C for 61 hours at ambient pressure, which is lower than previously reported. The optimized samples have revealed the superconducting transition temperature ( T c onset ) of 43 K for GdFeAsO 0.83 F 0.17 . The first-time reported critical current J c value for this Gd1111 is observed of the order of 10 3 A/cm 2 at 0 T and 5 K. Our investigation also concluded that highly pure precursors, particularly gadolinium metal, are required to achieve the superconducting properties of F-doped Gd1111. A high growth pressure of 1 GPa reduces the superconducting properties of F-doped Gd1111.