Effect of the substitution of Fe, Co, Ni for Cu in YBa2Cu3O7-δ studied by anelastic relaxation measurements

Measurements of elastic energy dissipation have been made on specimens with substitution of Fe, Co, Ni for Cu in YBa2Cu3O7-δ. The effect of substitution on the double internal-friction peaks around Tc was found to be different for substitution of Fe, Co on the Cu(1) site along the Cu-O chain and substitution of Ni on the Cu(2) site on the Cu-O2 plane. The origin of the double peaks around Tc is discussed on the basis of experimental results. A new internal friction peak that appeared at 190 K is also reported in the paper. (orig.)