Low-temperature synthesis, structural and magnetic properties of self-dopant LaMnO_(3+δ) nanoparticles from a metal-organic polymeric precursor

摘要

Self-dopant LaMnO_(3+δ) nanoparticles have been successfully synthesized by metal citrate complex method based on Pechini-type reaction route, at low temperature (773 K). Powder X-ray diffraction and transmission electron microscope revealed pure and nanostructured phase of LaMnO_(3+δ) [δ = 0.125) with an average grain size of ～72 nm (773 K) and ～80 nm (1173 K). DC-magnetization measurements under an applied magnetic field of H = ±60 kOe showed an increase in the magnetization with the increase of calcination temperature. Ferromagnetic nature shown by non-stoichiometric LaMnO_(3+δ) was verified by well-defined hysteresis loop with large remanent magnetization (M_r) and coercive field (H_c). Surface areas of LaMnO_(3+δ) nanoparticles were found to be 157.4 and 153 m~2 g~(-1) for the samples annealed at 773 K and 1173 K, respectively.