Effects of DL-alanine fuel and annealing on auto-combustion derived MgFe_2O_4 powder with low carbon content and improved magnetic properties

摘要

Structural and magnetic properties of as-prepared and annealed MgFe_2O_4 nano-powders prepared by auto-combustion method using DL-alanine fuel have been investigated. Nanoparticles with single-crystal electron diffraction patterns are analyzed, and phase purity is confirmed by X-ray diffraction and Raman and infrared spectroscopy. Residual carbon (C), hydrogen (H) and nitrogen (N) content in as-prepared powders is found to reduce by annealing the powders at 900 °C in air. Annealing the as-prepared powders in the range (600-1200 °C) increases the crystallite size from 35 to 46 nm, and increases saturation magnetization to 36 emu/g with low coercivity of ～33 Oe. Variations in the magnetic properties are correlated with changes in cation distribution in the octahedral and tetrahedral sites estimated from X-ray diffraction and magnetic studies.