Structure, nonstoichiometry and thermal expansion of the NdBa(Co,Fe)2O5+δ layered perovskite

NdBaCo2−xFexO5+δ (0.0 ≤ x ≤ 2.0) series were prepared by a solid state reaction. Singe phase solid solutions were obtained within the range 0.0 ≤ x ≤ 1.4. The crystal structure of iron substituted solid solutions NdBaCo2−xFexO5 + δ was described within the tetragonal unit cell ap × ap × 2ap (S.G. P4/mmm). The substitution of cobalt for iron leads to the monotonous increase of the unit cell parameters and the unit cell volume. The values of the oxygen content in NdBaCo2−xFexO5 + δ (x = 0; 0.2) as a function of temperature were determined by TGA. The thermal expansion measurements of NdBaCo2−xFexO5 + δ (x = 0; 0.2; 0.4; 0.6 and 0.8) were performed. Chemical expansion constituent was separated.