Abstract
► Stabilizing oxygen content by using extra oxygen resulted from HfO2. ► Understanding the interactions of Hf(IV) with YBCO and its effect on different vibrational modes. ► Promotion of the mechanical properties of 123-YBCO specially mechanical tensile. ► Application of hafnium as softener material to increase ductility of YBCO.
The pure YBCO (YBa2Cu3O7) and its variant hafnium containing superconductors with general formula: Y1−xHfxBa2Cu3Oz, where x=0.1, 0.2, and 0.4mole, respectively, were synthesized by solution route using urea as precursor forming agent. X-ray measurements indicated that Hf4+ ions have a negligible effect on the main crystalline structure and substitute Y-sites successfully in lattice structure of 123-YBCO at low levels of hafnium doping (x=0.1→0.2mole). From SE-microscopy mapping and EDX elemental analysis Hf4+ was detected qualitatively with good approximation to the actual molar ratio but not observed at 123-YBCO grain boundaries which confirm that hafnium (IV) has diffused regularly into material bulk of superconducting 123-YBCO-phase at low levels of concentrations. Structure visualization of Hf-doped-123-YBCO was made to confirm success of hafnium substitutions inside crystal lattice on Y-sites of 123-YBCO superconductors. Hafnium dopings affected sharply on the main vibrating modes of YBCO regime particularly on the apical oxygen (O4) vibrational mode A1g. Magnetic susceptibility measurements proved that hafnium dopings have strong effect on the transport properties of YBCO-composites regime. Hafnium promotes mechanical tensile coefficient recording maxima 35.7MPa for x=0.4mole.