Structural and magnetic characterization of nanocrystalline LaFeO₃ synthesized by low temperature combustion technique using different fuels

Abstract

Synthesis of nanocrystalline LaFeO₃ with fine particle size by a simple combustion method employing urea and polyvinyl alcohol as combustion fuels without using water or any other solvent is reported. Rietveld structural refinement analysis of the powder X-ray diffraction data indicates that LaFeO₃ crystallizes in the orthorhombic perovskite structure with space group <em> Pbnm</em>. The values of unit cell volume and X-ray density of the samples remain almost constant, indicating the efficiency of the combustion method. The average grain size of LaFeO₃ powders obtained with urea as a fuel is smaller, while the specific surface area is larger than that of the nanopowder obtained with polyvinyl alcohol. Both the phases show antiferromagnetic behavior and antiferromagnetic interactions are dominant in the phase synthesized by polyvinyl alcohol. Anti-ferromagnetic behavior of the samples may be due to super-exchange Fe³⁺–O^2-–Fe³⁺ interactions.