Synthesis and magnetic properties of LiFe5O8 powders by a sol-gel process

LiFe5O8 ferrite has been prepared by a sol-gel method. The crystal structure was found to be cubic spinel structure with a lattice constant a = 0.8336 nin. LiFe5O8 powders that were annealed at and above 1173 K have a single-phase spinel structure. However, powders annealed at 973 and 1073 K have a typical spinel structure with small amount of hematite (alpha-Fe2O3) phase. The Neel temperature of LiFe5O8 was T-N = 905 +/- 3 K. The isomer shift values at room temperature for the A and B patterns are found to be 0.18 and 0.21 mm/s relative to the Fe metal, respectively, which are consistent with high-spin Fe3+ charge states. The saturation magnetization MS was 64.4 emu/g at room temperature under the applied magnetic field of 10 kOe after annealing at 1273 K in air atmosphere for 6 h. (c) 2004 Elsevier B.V. All rights reserved.