The effect of oxygen partial pressure and cooling rate during processing on the critical current density and grain coupling of Bi-2212/Ag tapes

We discuss the reason why high oxygen partial pressure (P-O2) heat treatment is effective in increasing the critical current density (J(c)) of Bi2Sr2CaCu2Oy (Bi-2212)/Ag tapes prepared by a partial melting and subsequent slow cooling method. The high J(c) values obtained by the high P-O2 heat treatment is attributed to the strong coupling of grains due to the suppression of the formation of non-superconducting phases at grain boundaries and the decrease of anisotropy due to the high oxygen content of the Bi-2212.