Extended family of new Bi-2222 superconducting cuprates Bi₂Sr₂(RE_1-xCe_x)₂Cu₂O_10+y, RE=rare earth

We report the synthesis of a new class of layered cuprates with BiO bilayers: Bi2Sr2(RE1-xCex)2Cu2O10+y (Bi-2222 phase) with RE=Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm (at x=0.18). Superconductivity is observed for RE=Y, Nd, Sm, Eu, Gd, Dy and Ho, but not for Pr, Tb, Er and Tm. The transition temperature (Tc) is highest for the Gd derivative (34K) and progressively decreases for larger or smaller RE ions. The origin of this effect is discussed. © 1990.