Permeability and microstructure of manganese modified lithium ferrite prepared by sol–gel auto-combustion method

A series of manganese modified lithium ferrite powders, Li0.5Fe2.5O4 with different content of Mn (0, 0.05, 0.1, 0.15, 0.20, 0.25) were directly prepared by a novel sol–gel auto-combustion method at room temperature. The average particle sizes of as-synthesized powders were 50 nm and exhibited high activity and homogenous chemical composition. The lithium ferrites prepared by as-synthesized powders can be sintered at as low as 950 °C. Experimental results show that the lattice constant of all the ferrites increases linearly with the increasing of Mn content. The effects of Mn content on initial permeability and microstructure were studied. All the samples exhibited good magnetic properties and initial permeability was strongly influenced by the Mn content. The low temperature sintered samples have fine-grained microstructure and the grain sizes are largely dependent on added Mn content. The sol–gel auto-combustion process was believed to the main reason for low temperature sintering Mn modified lithium ferrites.