Effect of Fe2O3 Nano-Oxide Addition on the Superconducting Properties of the (Bi,Pb)-2223 Phase

Abstract

The effect of different weight percentages of nano-Fe2O3 on the properties of Bi1.8Pb0⋅4Sr2Ca2Cu3O10+δ superconducting phase was studied. Phase formation, elemental real contents and granular microstructure of the investigated samples were carried out using X-Ray powder Diffraction (XRD), Energy Dispersive X-ray emission (EDX), Proton Induced X-ray Emission (PIXE), Rutherford Backscattering Spectrometry (RBS) and Scanning Electron Microscopy (SEM). XRD data indicated that the volume fraction of (Bi,Pb)-2223 decreased as nano-Fe2O3 wt.% increased. PIXE and EDX analyses showed that the PIXE technique is more accurate for detecting the nano-Fe2O3 than the EDX technique. The oxygen content, determined from RBS, decreased as nano-Fe2O3 wt.% increased. The superconducting properties of the prepared samples were investigated using electrical resistivity and I–V curves, at 77 K, measurements. It was found that the granular structure and the critical current density were improved up to 0.2 wt.% of nano-Fe2O3 addition. The superconducting transition temperature T c decreased as nano-Fe2O3 wt.% increased, attributing this to the decrease of the volume fraction or trapping of mobile holes. The enhancement rate of J c for (Bi,Pb)-2223 phase added with nano-Fe2O3 is 9 %, which is lower than that of (Bi,Pb)-2223 phase added with SnO2, Ag2O, Al2O3 and MgO. This means that the nano-magnetic addition has the lowest enhancement rate in both J c and T c.