Nanocrystalline LiFe5O8 and Li0.5Fe2.3Cr0.2O4 particles ranging from several nm to several hundred nm in size have been prepared by the poly(ethylene glycol) gel method. Their structure and magnetic properties were examined. It was found that the specific saturation magnetization σs of these particles decrease with decreasing particle size. The Curie temperature of LiFe5O8 particle 8.1 nm in diameter decreases to 590°C and is 50°C lower than that of the bulk. From the specific magnetization σ versus temperature T curve of nanocrystalline LiFe5O8 particle (9.1 nm in diameter), it seems that this sample consists of two magnetic phases. These phenomena are discussed in terms of superparamagnetism and surface magnetism.
- Lithium ferrite
- Magnetic properties