Effect of Ta2O5 addition on the superconducting properties of REBa2Cu3Oy

We have investigated the effect of Ta2O5 addition on the superconducting properties of REBa2Cu3Oy (RE = Er, Sm and Eu: REBCO) prepared by a powder-sintering method. Tc(zero) values showed no degradation up to 1.0 wt.% Ta2O5 addition for ErBCO samples. EuBCO and SmBCO samples showed the increase in Tc(zero) from 89 K to 94 K by the addition of 1 wt.% Ta2O5, and 80 K to 94 K by the addition of 2 wt.% Ta2O5, respectively. Jc values at B = 0.5 T increased by two times the pure samples for ErBCO with 1.0 wt.% addition, four times for EuBCO with 1.5 wt.% addition, and 33 times for SmBCO with 1.0 wt.% addition. The formation of REBa2TaO6 was observed for the Ta2O5-added REBCO samples.