Auto-combustion synthesis of nanocrystalline LaFeO3

Nanocrystalline LaFeO3 with particle size of about 30 nm was directly synthesized by sol–gel auto-combustion method at room temperature. The overall process involves three steps: formation of homogeneous sol; formation of dried gel; and combustion of the dried gel. Experiments revealed that LaFeO3 dried gel derived from citrate and nitrate sol exhibits self-propagating combustion at room temperature once it is ignited in air. After auto-combustion, the desired nanocrystalline LaFeO3 was acquired and no further calcination was needed. The auto-combustion was considered as a heat-induced exothermic oxidation–reduction reaction between nitrate ions and carboxyl group. The coercivity of the nanocrystalline LaFeO3 is 98.82 G, while the saturation magnetization is only 2.75 emu g−1. The DTA–TG and IR were used to study the auto-combustion and thermal decomposition of the precursor. The structure and magnetic properties of the nanocrystalline LaFeO3 were characterized by XRD and VSM techniques.