Magnetic field dependence of the resistivity and susceptibility of the above-100-K Bi-Sr-Ca-Cu superconductor

The magnetic field dependence of the resistivity and susceptibility of multiphase Bi-Sr-Ca-Cu-O compounds exhibiting transport and diamagnetic anomalies at 115 and 75 K are reported. The field dependence of the latter yields values of Hc1 and dHc2dT(T=Tc) very similar to those found for the Y(R)Ba2Cu3O7-x family of Cu perovskitelike superconductors. The field dependence of the above-100-K region strongly suggests that bulk superconductivity, as opposed to filamentary or fluctuation behavior, dominates at these temperatures. © 1988 The American Physical Society.