Synthesis, characterization, and Vickers microhardness for (YIG)x/(Bi,Pb)-2223 superconducting phase

Abstract

The current study investigated the effect of adding yttrium iron garnet (Y3Fe5O12; YIG) nanoparticles to the (Bi1.8Pb0.4)Sr2Ca2.1Cu3.2Oy ((Bi,Pb)-2223) superconductor. The classical solid-state reaction technique was used to synthesize the nano-(YIG)x/(Bi,Pb)-2223 composites (0.00 ≤ x ≤ 2.00 wt.%). X-ray diffraction (XRD) confirmed the formation of tetragonal (Bi,Pb)-2223 as the major phase. The morphology and elemental composition of the synthesized samples were investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), respectively. Iodometric titration analysis proved that the addition of nano-YIG increased the oxygen content in the CuO2 planes. The critical transition temperature (Tc) and the critical current density (Jc) increased with the nano-YIG addition up to x = 0.25 wt.% with values of 119.25 K and 638.37 A/cm2, respectively. X-ray photoelectron spectroscopy (XPS) revealed the elemental composition and oxidation state of all elements in the prepared samples. Room temperature Vickers microhardness (Hv) measurements were performed at different applied loads (0.49–9.80 N) and a duration time of 20 s. The best enhancement in Vickers microhardness (Hv) was achieved at x = 2.00 wt.%. The modified proportional sample resistance (MPSR) model provided the best theoretical analysis at the plateau limit region based on Vickers microhardness (Hv) observations. Moreover, nano-YIG addition into the (Bi,Pb)-2223 superconductor adversely affected several mechanical parameters such as the elastic modulus (E), yield strength (Y), and fracture toughness (K).