Formation of the desired phases, iron oxide and LSF731, was
confirmed by XRD analyses (not shown here) of the composite
materials prepared by either mechanical mixing or a modified
Pechini method. Reaction between iron and strontium to form
strontium ferrites at high temperature could take place to a small
extent during the preparation of the composite materials.
Nevertheless, this interfacial phase was not detected in the XRD
analyses performed. Galinsky et al. found that strontium ferrite
phase coexisted with the perovskite and iron oxide due to an
incomplete solid-state reaction during the preparation of a composite
material. After the first redox cycle in a TGA, the ferrite
was incorporated to the LSF structure