Production, structure and magnetic properties of nanocomposites based on the perovskite phase LaFeO3

Abstract

The phase relations in the La₂O₃–Fe₂O₃ system at 1300 °C were studied in the whole concentration range by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The samples were prepared with a concentration step of 1–5 mol %. The isothermal cross-sections of the La₂O₃–Fe₂O₃ phase diagram at 1300 °C are characterized by the presence of three single-phase (A–La₂O₃, LaFeO₃, Fe₂O₃), two two-phase (A–La₂O₃+LaFeO₃, LaFeO₃+Fe₂O₃) regions. The composition corresponding to the perovskite phase is 49 mol % La₂O₃–51 mol % Fe₂O₃. Nanocomposites based on the perovskite phase (LaFeO₃) were obtained by the Pechini method and heterogeneous precipitation from nitrate solutions. Solutions of La³⁺ nitrates, which were obtained by dissolving lanthanum oxide with a content of the main component of 99.99 % in nitric acid. The influence of the production method on the microstructure, morphology, and magnetic properties of nanopowders (LaFeO₃) was studied. According to XRD, infrared spectroscopy, SEM, and TEM, the synthesized perovskite LaFeO₃ is single-phase with a particle size of 50–60 nm. The morphology of powder particles primarily depends on the method of material synthesis. The powder showed ferrimagnetic magnetic properties and had a specific magnetization 0.2 and 0.15 emu/g.