Superconductivity Properties of Bi-2223 Ceramics Substituted with Strontium Sites at Large Scale Nano-Sized Europium Nanoparticles

Ceramic superconductor materials with an initial composition of Bi1.7Pb0.3Sr2Ca2Cu2.75Na0.25Oy and doping ratios of x = 0, 0.2, 0.25 and 0.3 were produced using the solid-state reaction method The effect of substituting high-nano-sized europium (80 nm) for Strontium on phase formation, morphological structure and superconducting properties were analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity (R-T) and magnetisation (M-H) measurements. XRD measurements revealed the formation of the Bi-2223 high-temperature phase, the Bi-2212 low-temperature superconducting phase, and secondary phases in all samples. Despite the formation of secondary phases, the primary phase structure was superconducting in all samples. However, the phase structure gradually deteriorated with increasing amounts of nanoparticle substitution. Scanning electron microscopy (SEM) microstructure analysis of the samples showed the existence of plate-like grains, which suggested the production of both B-2212 and Bi-2223 grain structures. In the electrical measurement results, superconductivity was exhibited in the samples up to the substitution value x = 30. In the sample containing nano-sized Eu at x = 0.20, the value of the superconductivity transition temperature increased due to the decrease in impurity phase density. M-H measurements were performed to characterize the magnetic properties of the samples. In M-H measurements, closed-loop hysteresis, a characteristic feature of Bi-2223 superconductors, occurred in a uniformly shaped sample containing no nano-sized europium. However, the hysteresis area decreased with increasing substitution, indicating a deterioration in magnetic properties.