Thermal evolution of the microstructure of nanosized LaFeO₃ powders from the thermal decomposition of a heteronuclear complex, La[Fe(CN)₆] · 5H₂O

The thermal decomposition of a heteronuclear complex, La[Fe(CN)₆] · 5H₂O, leads to the preparation of nanosized single-phase perovskite-type LaFeO₃ powders. The microstructural evolution of LaFeO₃ with the temperature has been studied by x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The product of the decomposition at 500 °C consists of nanoporous grains which have the morphology of the complex, but diffracting as a monocrystal of LaFeO₃. At the higher temperatures, the nanosized particles start to separate from each other, still keeping the shape of the complex grains and forming soft agglomerates. The formation of LaFeO₃ from the complex at low temperatures is facilitated by the formation of an orthorhombic transition phase.