Using ex situ X-ray powder diffraction at synchrotron radiation to follow changes in the phase composition of perovskite-like strontium cobaltites

Precision X-ray diffraction at synchrotron radiation was used to reveal the separation of perovskite-like oxides SrCo0.8-x Fe0.2Nb x O3-z (x = 0.2 and 0.3) into two phases of a similar structure identical to initial perovskite structure, but having different unit cell parameters and supposedly different oxygen deficiency. The structural transformation is accompanied by oxygen outlet from the structure. The study of oxygen atoms intercalation from air into the oxygen-deficient structure showed that the structural changes are reversible: heating to 400°C in air restores the initial state of samples.