The effect of lanthanide substitution on the superconductivity in Ba2YCu3O7 and (La,Sr)2CuO4 (invited)

Abstract

The effect of the lanthanide substitution on the superconductivity in Ba₂YCu₃O₇ and (La,Sr)₂CuO₄ is investigated. The substitution effect is completely different between the two Cu‐oxide systems. In Ba₂YCu₃O₇, the replacement of Y with lanthanides gives negligible change in the transition temperature, whereas a few percent of lanthanide substitution depresses T_c by about 10 K in the (La,Sr)₂CuO₄ system. The depression of T_c in the latter system depends on the atomic number of lanthanides. From the results of the magnetic susceptibility and the relationship between the lattice parameters and T_c, we conclude that the depression of T_c cannot be ascribed to the magnetic effect nor to the volume effect. Possible mechanisms for the depression of T_c are discussed.