Abstract
Nanocrystalline lithium ferrite (LiFe
5O
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
°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
5O
8 phase started to form at around 520
°C. XRD indicated that LiFe
5O
8 phase always contained α-Fe
2O
3 impurity and the hematite phase formation increased by increasing the annealing temperature ⩾850
°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
°C. Single well crystalline LiFe
5O
8 phase was obtained at Fe
3+/Li
+ mole ratio 3.33 and annealing temperatures from 800 to 1000
°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
°C.