Superconducting and Magnetic Properties of Zn-doped YBa2Cu3O7−δ

Abstract

The superconducting properties and AC/DC magnetic properties of YBa2Cu3−xZnxO7−δ, (x=0.0, 0.01, 0.03, 0.05, 0.10 and 0.15) compounds were investigated. Samples were synthesized through solid-state reaction route. X-ray diffraction data confirms the single-phase orthorhombic/tetragonal crystallization for the studied samples. Thermo-Gravimetric Analysis (TGA) was done for pure and Zn-doped YBa2Cu3O7−δ (YBCO) samples. Results reveal that at higher dopant levels the doped samples are more oxygen-deficient than the undoped ones. The superconducting properties of YBa2Cu3−xZnxO7−δ system always enhance with addition of oxygen to Cu–O chains, which causes enhancement of superconducting carrier density together with orthorhombic structure. Zn substitution causes an overall reduction of superconducting condensation energy with systematic degradation of superconducting properties like Tc and Jc. This occurs via induced non-homogeneity of hole carrier density created by extended nature of perturbation on electronic structure in CuO2 planes and its weak-link type behavior. AC susceptibility measurement reveals that Zn doping reduces the inter-granular couplings. Scanning Electron Microscope (SEM) images indicate that increment of average grain size with increasing of Zn concentration.