Crystal Structures and Electrical Properties of L_1.5Ba_1.5Cu₃O_y(L=La, Pr, Nd, Sm, Eu, Gd, Y and Yb)

Abstract

The L 1.5 Ba 1.5 Cu 3 O y compounds for L=lanthanides have been investigated by X-ray powder diffraction analysis and electrical resistivity measurement. A single L 1.5 Ba 1.5 Cu 3 O y phase has been firstly obtained in the samples for L=Nd, Sm and Eu as well as La and Pr exhibiting the semiconductor-like behavior of resistivity down to about 10 K. This single phase has not been obtained in the samples for L=Gd, Y and Yb having the LBa 2 Cu 3 O y and L 2 BaCuO y phases and exhibiting the superconductivity. The stability of the L 1.5 Ba 1.5 Cu 3 O y single phase is found to depend on the L 3+ ion radius and sintering condition.