Synthesis and characterization of core-shell Ni/NiO nanoparticles/CuTl-1223 superconductor composites

Core-shell nickel/nickel-oxide (Ni/NiO) nanoparticles/Cu0.5Tl0.5Ba2Ca2Cu3O10−δ (CuTl-1223) superconductor composites were synthesized by solid-state reaction. The effect of these nanoparticles inclusion on structural and superconducting properties of CuTl-1223 matrix was investigated. Structural, morphological, and compositional properties were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy respectively. Superconducting transport properties were explored by dc-resistivity (ρ) measurements and the different oxygen vibrational modes of the composites were observed by Fourier transforms infrared (FTIR) spectroscopy. The variation of critical temperature (Tc) depends upon the nanoparticles contents in the host superconducting matrix. The overall suppression of Tc with increasing nanoparticles concentration is most probably due to trapping of mobile free carriers and pair-breaking caused by the reflection/scattering of carriers across these nanoparticles having net magnetic moment of metallic nickel in the core of nanoparticles.