Superconducting and microstructure properties of Eu2O3 nanoparticles substitution in low density Bi(Pb)-2223 superconductor

Abstract

The effects of Eu₂O₃ nanoparticles substitution on superconducting and structural properties of low density Bi_1.6Pb_0.4Sr₂(Ca_2-xEu_x)Cu₃O_y cuprates superconductors where x = 0.00, 0.0025, 0.02, 0.05 and 0.07 have been investigated. All samples used in this research have been prepared by solid state reaction technique. A low-density sample was formed by including crystalline sucrose during the pelletization process and subsequently subjected to combustion at a temperature of 400 °C for a duration of two hours. Several characterization techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), four-point probe method and AC Susceptibility (ACS) were performed on all prepared samples. Phase examination by X-ray diffraction (XRD) revealed that the crystallographic structure has shifted slightly from tetragonal to orthorhombic. As the concentration of Eu nanoparticles increased, the quantity of 2223 phase exhibited a consistent decline, suggesting that the incorporation of Eu nanoparticles promotes the formation of 2212 phases. The crystallite size were estimated through Williamson-Hall and Scherer equations. The FESEM images reveal that an increase in Eu concentration leads to a reduction in the size of plate-like grains, resulting in a more random and dispersed arrangement without any specific alignment. Sample with x = 0.0025 Eu₂O₃ nanoparticles yields the highest J_c value compared to Eu-free sample. The present results show that the optimal performance sample was found at sample with x = 0.0025.