YBa2Cu3O7-d Bulk Superconductors: Exploring the Impact of Two Synthesis Techniques on the Microstructure and Critical Temperature

Abstract

This study explores the synthesis and characterization of high-performance YBa2Cu3O7-δ (YBCO) superconductors via two methods: the established solid-state reaction (SSR) and a novel modified thermal decomposition (DM) technique. Notably, the DM method employs metal acetates as a single precursor for synthesis, contrasting the SSR method which utilizes oxides and carbonates as the primary metals. Two samples were prepared: YBCO-SSR and YBCO-DM. X-ray diffraction (XRD) analysis confirmed the formation of the dominant YBCO phase in both, with minor secondary phases namely, Y2BaCuO5-x (Y211) and CuO. FESEM analyses revealed marked differences in microstructure, with the DM-prepared sample exhibiting a smaller average grain size and denser packing compared to its SSR counterpart. These observations demonstrate that the modified thermal decomposition method produces an enhanced, denser, and more homogeneous microstructure for the YBCO-DM sample, which contributes to its improved superconducting properties. Moreover, the DM-prepared sample exhibited a higher superconducting transition temperature (Tc-onset) of approximately 93.24 K, compared to 91.27 K for YBCO-SSR. Additionally, the DM sample displayed a sharper transition width (ΔTc) of 3.45 K compared with 4.57 K for YBCO-SSR. These observations suggest that the DM technique enhances the superconductivity of YBCO which is potentially attributed to the use of acetates as starting materials which can effectively dissolve yttrium, barium, and copper ions, leading to a more ordered distribution and better superconducting properties.