A study on the magnetic properties of the lithium ferrite nanocrystallites

The magnetic properties of lithium ferrite nanocrystallites ranging from 9.1 to 860 nm have been studied. The specific saturation magnetization σ_s of these nanocrystallites decrease lineally with the nanocrystallite size. The specific magnetization versus temperature curves σ (T) and Mössbauer spectra of sample A (diameter D = 860 nm), sample B (D = 11.8 nm) and sample C (D = 9.1 nm) have been measured. It is found that the Curie temperatures of samples B and C are 50°C lower than that of sample A. From the σ(T) curve of sample C, it seems that sample C consists of two magnetic phases. These phenomena have been discussed with the superparamagnetism and the surface magnetism of sample C.