Surface elemental composition, chemical state, optical properties and room temperature ferromagnetic behaviour of Sr-substituted LaFeO3 prepared using -D-fructose assisted solution combustion technique

Abstract

La_1-xSr_xFeO₃ (x = 0, 0.5 and 1) perovskites were synthesized through solution combustion method using -D-fructose as carbohydrate mediator. The crystallographic structure, size, microstrain, dislocation density and packing factor were estimated from X-ray diffraction patterns. The phase purity, refined lattice constants and lattice angles were confirmed via Rietveld profile refinement. The optical band gap corresponding to direct allowed transitions and the vibrational bands corresponding to functional groups and metallic sites present in the samples were obtained one-to-one, from the reflectance data in UV visible spectrum and Fourier transform infrared spectroscopy. The morphology and the composition in the samples were investigated using scanning electron microscopy with EDX. The valid chemical composition and oxidation states of cations were elucidated using X-ray photon spectroscopy. The room temperature M–H loops extracted from VSM data illustrated broader or nearly the same hysteresis and enhanced saturation magnetization as the concentration of Sr-substitution varies from x = 0 to 1 through x = 0.5. The transition from antiferromagnetic LaFeO₃ with weak canted ferromagnetic component to a strong ferromagnetic SrFeO₃ is evident from the room temperature VSM data.