Synthesis and characterization of lithium ferrite by oxalate precursor route

Nanocrystalline lithium ferrite (LiFe(5)O(8)) powders have been synthesized by oxalate precursor route. The effects of Fe(3+)/Li(+) mole ratio, and annealing temperature on the formation, crystalline size, morphology and magnetic properties were systematically studied. The Fe(3+)/Li(+) mole ratio was controlled from 5 to 3.33 while the annealing temperature was controlled from 600 to 1100 degrees C. The resultant powders were investigated by differential thermal analyzer (DTA), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). DTA results showed that LiFe(5)O(8) phase started to form at around 520 degrees C. XRD indicated that LiFe(5)O(8) phase always contained alpha-Fe(2)O(3) impurity and the hematite phase formation increased by increasing the annealing temperature >= 850 degrees C for different Fe(3+)/Li(+) mole ratios 5, 4.55 and 3.85. Moreover, lithium ferrite phase was formed with high conversion percentage at critical annealing temperature 750-800 degrees C. Single well crystalline LiFe(5)O(8) phase was obtained at Fe(3+)/Li(+) mole ratio 3.33 and annealing temperatures from 800 to 1000 degrees C. Maximum saturation magnetization (68.7 emu/g) was achieved for the formed lithium ferrite phase at Fe(3+)/Li(+) mole ratio 3.33 and annealing temperature 1000 degrees C. (C) 2008 Elsevier B.V. All rights reserved.