SUPERCONDUCTIVITY IN THE NEW HIGH-T_C SUPERCONDUCTORS RBa₂Cu₃O_9-y(R=Y, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb)

Superconductivities in the 90K range as measured by resistance and magnetic susceptibility are reported for RBa₂Cu₃O_9-y(R=Y, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb) having the orthorhornbic perovskite structure. Unstable resistance drop above 100K has been found in ErBCO, probably associated with interfacial superconductivity.