Role of improving the physical properties of Sm-123 phase by adding nano-magnetic MnFe2O4

Abstract

Superconducting samples of SmBa2Cu3O7−δ (Sm-123) added with various amounts of nanosized MnFe2O4 addition (0.0−0.20wt%) were investigated. The investigated samples prepared by the solid-state reaction method. The phase formation and microstructure of these samples were examined using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), proton induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS). XRD data indicate that the volume fraction of Sm-123 increases as nanosized MnFe2O4 increases up to 0.02wt%. The elemental distribution and oxygen content were deduced from PIXE and RBS. The oxygen content slightly decreases as MnFe2O4 wt% increases. The superconducting transition temperature (Tc) and critical current density (Jc) of the prepared samples were estimated from electrical resistivity and transport critical current density measurements. It was found that Tc decreases as nanosized MnFe2O4 addition increases, while Jc enhances up to 0.02wt%. Moreover, the temperature dependence of normal state electrical resistivity was studied in view of the pseudogap opening in order to determine the pseudogap temperature T* as a function of nanosized MnFe2O4 addition. T* increases as nanosized MnFe2O4 increased, indicating the enhancement of the pseudogap formation in HTSCs by adding magnetic impurities. The crossover to fluctuation conductivity near the Tc is discussed.