Enhancement of Critical Current Density in YBa2Cu3O7−y HTS Through Boron Addition

The effect of B 2 O 3 addition on the superconducting transition and grain boundary critical current density of the boron free (control) and boron doped HTS ceramics with nominal composition YBa 2 Cu 3 B x O 7− y ( x =0, 0.025, 0.05, 0.075, 0.1 and 0.15) has been investigated. For the lowest-level boron doping ( x =0.025) an increase by nearly 1.5 times was observed in the critical current density J c compared to the control sample. The small additives of boron in YBa 2 Cu 3 B x O 7− y ( x =0.025 and 0.05) do not essentially affect the critical temperature T c =92.5 K of nominally pure Y123. Higher-level boron added compounds revealed a decrease in both T c and J c values. The data obtained indicate the possibility of boron dopant being inserted either into interstitial or into substitutional sites of the lattice.