We have studied the structural and superconducting properties of two samples superconductors Nd(SrBa)Cu3O6+z. One was a conventionally annealed sample at 450°C in oxygen (0) and the other was heated in argon at 850°C followed by oxygen annealing (A0). The Tc of the sample (O) was 68 K and that of (AO) sample was 78 K. This was confirmed by our AC susceptibility, resistivity and Seebeck effect measurements. Further, there was an enhancement in the shielding and the intergranular critical current. The X-ray and neutron data showed a tetragonal structure, and that the (O) sample had a higher impurity level arising from Nd entering the Sr/Ba sites that may result in a decrease in the carrier density (p) which also was confirmed by our thermopower measurements. A combination of several factors such as changes in the Cu (1) apical oxygen distance, chain oxygen ordering, increase in p and in-phase purity for the (AO) sample may qualitatively account for the observed data.We have studied the structural and superconducting properties of two samples superconductors Nd(SrBa)Cu3O6+z. One was a conventionally annealed sample at 450°C in oxygen (0) and the other was heated in argon at 850°C followed by oxygen annealing (A0). The Tc of the sample (O) was 68 K and that of (AO) sample was 78 K. This was confirmed by our AC susceptibility, resistivity and Seebeck effect measurements. Further, there was an enhancement in the shielding and the intergranular critical current. The X-ray and neutron data showed a tetragonal structure, and that the (O) sample had a higher impurity level arising from Nd entering the Sr/Ba sites that may result in a decrease in the carrier density (p) which also was confirmed by our thermopower measurements. A combination of several factors such as changes in the Cu (1) apical oxygen distance, chain oxygen ordering, increase in p and in-phase purity for the (AO) sample may qualitatively account for the observed data
