Effect of three rare earth elements (Gd, Sm, Eu) on superconducting properties of RE Ba2Cu3Ox

YGdSm)123 sample with nominal composition (Y0.33 Gd0.33 Sm0.33)Ba 2 Cu 3 O X, also YGdEu1 and YGdEu2 samples with nominal composition (Y0.33 Gd0.33 Eu0.33)Ba2 Cu3 OX were prepared at different oxygenation conditions. All the samples were analysed by ac susceptibility, resistivity, critical current density (Jc), SEM,XRD and EDX. The critical current density measurements show that the Jc increases in (YGdSm)123 and YGdEu1 samples comparing to (Y123) sample, so that the value of Jc in YGdEu1 is almost 2 times greater than (Y123) sample. May be the presence of Eu and Sm ions on the BaO planes act as the impurity and lead to local pinning and so increases the critical current density.