Characterization and magnetic properties of BaSn_1−x Fe _x O₃ nanoparticles prepared by a modified sol–gel method

BaSn_1−x Fe _x O₃ (x = 0, 0.05, 0.075 and 0.1) nanoparticles were prepared by a modified sol–gel method. Phase, morphology and oxidation state of samples were characterized using X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy and X-ray absorption near-edge spectroscopy. XRD results show the main reflections of the perovskite-type cubic structure for all powders calcined at 1050 °C for 3 h in air. X-ray absorption measurements indicate the substitution of Fe³⁺ ions on the Sn site of the BaSnO₃ host. The field dependence of magnetization M–H curve measured at room temperature exhibits diamagnetic behavior for undoped sample, whereas Fe-doped samples show the clear M–H loops with saturation magnetization and coercive field in the order of 0.34–1.25 emu/g and 260 Oe, respectively. Ferromagnetic (FM) ordering is interpreted in terms of overlapping of polarons mediated through oxygen vacancy defects based on the bound magnetic polaron (BMP) model. Observed FM data are fitted well with the BMP model involving localized carriers and magnetic cations.