Thermal expansion and conductivity of Nd1-xSmxBa2-ySryO7-d cuprate solid solutions

It has been found that Nd1-xSmxBa2-ySryCu3O7-6 (NSBSCO)solid solutions are formed at up to 62,5 mol.% substitution of Ba for Sr and at any substitution degree of Nd for Sm. Crystal structure parameters for NSBSCO phases have been determined; their oxygen nonstoichiometry, thermal expansion and conductivity within 300-1100 K have been investigated. On dilatometric curves of cuprates (α=f(TΔI/I0=f(T)), anomalies have been observed near 450-550, 800 and 1000 K, caused by change of ordering degree and oxygen vacancy concentration in CuO1-5 layers of Nd1-xSmxBa2-ySryCu3O7-5 phase crystal structure. It has been found that in tetra-phase (δ> 0,5), NSBSCO conductivity activation energy increases greater with σ increasing, than in ortho-phase (δ< 0,5). (authors)