SUPPRESSION OF SUPERCONDUCTIVITY AND STRUCTURAL CHANGES IN R1-xPrxBa2Cu3O7-y (R=Sm, Gd, Er, Tm, Y)

Abstract

The compounds R 1-x Pr x Ba 2 Cu 3 O 7-y ( R = Sm , Gd , Er , Tm and Y ) have been prepared and examined for superconductivity and structural changes. It is observed that the superconducting transition temperature Tc of R 1-x Pr x Ba 2 Cu 3 O 7-y decreases monotonically with increasing Pr concentration for all systems. At constant Pr concentration, Tc decreases approximately linearly with increasing radius with R cations while the lattice constants a,b,c and unit cell volume V increase. The correlation of both the Tc and the lattice constants with the radius of R cations is the same as for 1:2:4, 2:4:7, and 1:2:1:2 compounds.