Ic - B - T Evaluation for High-Tc Superconductors in Pressurized/Depressurized Liquid Nitrogen

Critical current (
I
_c
) and
n
-values were evaluated for commercially available (Bi, Pb)
₂
Sr
₂
Ca
₂
Cu
₃
O
₁₀
(Bi-2223), GdBa
₂
Cu
₃
O
₇
(GdBCO) and (RE)Ba
₂
Cu
₃
O
₇
(REBCO, RE = rare earth) superconducting tapes. The transport properties were investigated in magnetic fields up to 1 T in various temperatures around 77 K. The measurements up to the transport current of 500 A were performed in pressurized and depressurized liquid nitrogen using a newly developed apparatus. Bi-2223 showed the largest
I
_c
for magnetic field parallel to the tape surface, whereas it showed the largest anisotropy. It was found that the in-field
I
_c
property of GdBCO was improved. The effect of artificial pinning centers introduced for REBCO was confirmed.