Structural, Microstructural, and Superconducting Properties of Si-substituted YBa2 Cu3 O7- δ Ceramics

Abstract

This study investigates the effect of Silicon (Si) substitution on the microstructure and superconducting properties of the Y Ba2(Cu1-x Si x)3 O7-δ high-temperature superconductor, with composition ranging from x = 0.00 to x = 0.03. Samples were synthesized using the conventional solid-state reaction method. The morphological and microstructural characteristics were examined using Scanning Electron Microscopy (SEM). The results indicate that while the pure sample (x = 0.00) exhibits rectangular block grains aligned in preferred directions, the Si-substituted samples show a tendency toward grain size reduction, with an average grain size found to be less than 2 \mu m for all compositions. Furthermore, the microstructure of the substituted samples reveals a higher degree of irregularity, flaky grain shapes, and increased porosity at higher Si concentrations, which significantly reduces the connectivity between grains. Although the study highlights morphological changes, these structural modifications are critical for understanding the superconducting behavior, as they directly impact the critical current density and overall material performance. The findings suggest that Si substitution influences the grain growth mechanism and density of the Y Ba2(Cu1-x Si x)3 O7-δ system, emphasizing the importance of optimizing processing parameters to maintain superconducting performance in polycrystalline ceramics.