Effect of Oxygen Flow During Sintering on the Structural, Superconducting and Microstructural Properties of YBa2Cu3O7-δ

Abstract

The oxygen content in YBa₂Cu₃O_7-δ (YBCO-123) plays a critical role in determining its structural and superconducting properties. In this work, the effect of oxygen flow during the sintering process on the structural, superconducting and microstructural characteristics of pure YBCO-123 was investigated. Samples were prepared using the conventional solid-state reaction method under identical thermal conditions, with and without oxygen flow during sintering. Phase formation and crystal structure were examined using X-ray diffraction (XRD), superconducting behavior was evaluated by AC magnetic susceptibility (ACS) and microstructural features were analyzed using field emission scanning electron microscopy (FESEM). XRD results confirmed that orthorhombic YBCO-123 was the dominant phase for both sintering conditions, with a small amount of Y₂BaCuO₅ (Y-211) secondary phase present. While phase composition differences were minimal, ACS measurement revealed that samples sintered with oxygen flow exhibited a higher superconducting transition temperature and a sharper transition, indicating improved oxygen incorporation and enhanced intergranular coupling. FESEM analysis showed that oxygen-assisted sintering promoted grain growth, improved grain connectivity and reduced porosity. These findings demonstrate that oxygen flow effectively enhances the superconducting and microstructural properties of pure YBCO-123 which highlighting the importance of controlled oxygen environments during thermal processing.