Effect of Partial Lanthanide Substitutions of Gd123 Submicronic Powder

Abstract

GdLnxBa2-xCu3Oy (Ln = La, 0≤x≤ 0.6; Ln = Nd, Sm, Eu, 0≤x≤ 0.5) (Gd123:Ln) samples were synthesized using the sol-gel method. The homogeneity region, variation of the crystal lattice and oxygen stoichiometry of the Gd123:Ln solid solutions were studied as a function of the substitution degree x. It was shown that the homogeneity region becomes wider when going from Eu3+ (x≤ 0.35) to La3+ (x≤ 0.5), but for all lanthanides the symmetry changes from orthorhombic to tetragonal for x ~ 0.05. Measurements of the electrical resistance of Gd123:Ln samples in the temperature range 77−300 K revealed superconducting transition temperatures over 77 K only for ɯ = 0 and ɯ = 0.05.