LAUSR

Maghemite (γ-Fe2O3) nanoparticles and the (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ (CuTl-1223) superconducting phase were prepared separately by sol–gel and solid-state reactions, respectively. γ-Fe2O3 nanoparticles were added into the CuTl-1223 superconducting phase to get (γ-Fe2O3)x/CuTl-1223, where x = 0 ∼ 1.25 wt.% nanoparticle-superconductor composites. The structural, morphological, and superconducting transport properties of these composites were investigated by using different experimental techniques. X-ray diffraction (XRD) of these composites revealed that γ-Fe2O3nanoparticles have not changed the crystal structure of the host CuTl-1223 superconducting phase, which has indicated the occupancy of these nanoparticles at grain-boundaries. The grain morphology was improved due to change in reaction thermodynamics with addition of these magnetic nanoparticles. Superconducting transport parameters of the CuTl-1223 phase were enhanced up to a certain optimum level of γ-Fe2O3 nanoparticle content (i.e. x = 0.50 wt.%) followed by systematic suppression. Different microscopic superconducting parameters were deduced from resistivity versus temperature experimentaldata of (γ-Fe2O3)x/CuTl-1223, where x = 0 ∼1.25 wt.% composites by using different theoretical models.