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. (C) 2002 Elsevier Science B.V. All rights reserved.