Critical current density and mechanical strength of YBa 2Cu 3O 7−δ superconducting composites containing Zr, Ag and Y 2BaCuO 5 dispersions by melt-processing

Abstract

The high- T c YBa 2Cu 3O 7−δ composite superconductors containing Zr, Ag and Y 2BaCuO 5 have been fabricated by melt processing. Both the critical current density J M c and the flexural strength α max of these samples were measured. The value of J M c increased initially for all inclusions added. The microstructure analyses revealed that the Y 2BaCuO 5, Ag and BaZrO 3 were finely dispersed in the matrix. We believe that the fine dispersion of these inclusions is most likely responsible for an increase in J M c. The largest value of J M c we obtained is 64 800 A/cm 2 on the sample containing 50 mol.% Y 2BaCuO 5. In contrast, the value of α max was limited below 60 MPa due to the presence of mechanically weak grain boundaries. The addition of Ag to YBa 2Cu 3O 7−δ was effective in increasing both α max and J M c.