Transport critical current densities and magnetization in superconducting silver sheathed-Ag, Sn/YBCO composite wires

Magnetic-field dependences of transport critical current density J_c(B) and DC magnetization M were measured for silver sheathed YBCO superconducting wires to which various amounts of silver (Ag) and tin oxide (SnO₂) were added. Sample wires were fabricated by rolling and sintering at 910°C for 20 h. The short sample wire has a length of 4 cm and core diameter of 1 mm. Zero field transport critical current densities J_c (0) with small amounts of SnO₂ were more improved than with Ag addition. Concerning the field dependence of J_c (B), small amounts of SnO₂ addition were effective in increasing the J_c(B) in the low field region (B<10^-2 T) and intermediate field region (10^-2 T<B<10^-1 T). In the case of the ternary system (Ag+Sn/YBCO), the value of J_c(B) seems to be mainly dominated by SnO ₂ content