Synthesis and characterization of RuSr2NdxGd1-xCu2O8 compounds (x = 0, 0.03, 0.06, 0.12)

RuSr2NdxGd1-xCu2O8 samples (x=0, 0.03, 0.06 and 0.12) were synthesised by a solid state route, using mixed rare earth oxides (NdxGd1-x)2O3, prepared by a co-precipitation method, as precursors. Magnetoresistance measurements showed that the resistive transition temperature decreased and broadened with increasing Nd doping, suggesting that Nd really entered the lattice. The resistive transition curves in applied field exhibited typical polycrystalline behaviour with two peaks in their first derivative, identified as intra and intergrain superconducting transitions. XRD data also supported the fact that Nd ion entered the Ru-1212 lattice, yielding an ordered tetragonal structure at low Nd doping level. At higher Nd concentrations, the structure becomes disordered probably due to Nd/Sr solid solution.