Crystal structure, thermal and electrotransport properties of NdBa[1–x]Sr[x]FeCo[0.5]Cu[0.5]O[5+δ] (0.02 ≤ x ≤ 0.20) solid solutions

Abstract

Using solid-state reactions method, the solid solutions of layered oxygen- deficient perovskites NdBa[1–x[Sr[x]FeCo[0.5]Cu[0.5]O[5+δ] (0.02 ≤ x ≤ 0.20) were prepared; their crystal structure, thermal stability, thermal expansion, electrical conductivity and thermopower were studied. It was found that NdBa[1 x]Sr[FeCo[0.5]Cu[0.5]O5[+δ ]phases crystallize in tetragonal syngony(space group P4/mmm) and are p-type semiconductors, whose conductivity mcharacter at high temperatures changed to the metallic one due to evolution from the samples of so-called weakly-bonded oxygen. Partial substitution of barium by strontium in NdBaFeCo[0.5]Cu[0.5]O[5+δ] leads to the small decreasing of unitcell parameters, thermal stability and thermopower of NdBa[1–x]Sr[x]FeCo[0.5]Cu[0.5]O5[+δ] solid solutions, increasing of their electrical conductivity values and slightly affects their linear thermal expansion coefficient and activation energy of electrical transport values.