Polymer pyrolysis synthesis and magnetic properties of LaFeO3 nanoparticles

LaFeO3 nanoparticles were synthesized by a polymer pyrolysis method. LaFeO3 nanoparticles were successfully obtained from calcination of the precursor at different temperatures from 700 °C to 1000 °C in air for 3 h. The calcined LaFeO3 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), and vibrating sample magnetometry (VSM). The XRD and TEM results showed that all LaFeO3 samples had a single phase nature with the orthorhombic structure. The estimated crystallite sizes were in the range of 34.8±1.5-74.0±2.8 nm, as increased with increasing calcination temperature. The valence states of Fe ions were in the Fe3+ state, as confirmed by XANES results. The weak ferromagnetic behavior with the highest magnetization (M) of 0.32 emu/g measured at 10 kOe was obtained for the sample calcined at 700 °C. Moreover, this sample exhibited the Curie temperature (TC) above 400 K. The uncompensated spins at the surface was discussed as the origin of ferromagnetism of the LaFeO3 nanoparticles.