Effect of Yb2O3 additives on structure and transport properties of YBa2Cu3O7-δ

The effects of Yb2O3 particles on the microstructure and transport properties of YBa2Cu3O7-δ (YBCO) were investigated through resistance-temperature (R-T), scanning electron microscope (SEM), X-ray diffraction (XRD) and the critical current density (Jc) versus applied magnetic field (Jc-B) measurements. YBCO powder with Yb2O3 additives was synthesized using standard solid state reaction technique. Rietveld refinements of X-ray diffraction showed that both Yb2O3 and YBCO phases coexisted in the products. The critical current density (Jc) exhibited a maximum at x=0.05 in YBCO+xYb2O3 systems. Moreover, small additions of Yb2O3 in YBCO could enhance Jc by applying the magnetic field, although the superconducting temperature (Tc) decreased monotonically with increasing additive content. The characteristic behavior of Jc might come from the counterbalance of two effects simultaneously, which was caused by the inhomogeneity of grains distribution in nano-scale and degradation on superconducting properties.