Structural and some magnetic properties of manganese-substituted lithium ferrites

The structural and magnetic properties of Mn-substituted lithium ferrites having the general formula Li0.5−0.5xMnxFe2.5−0.5xO4 (where x=0.0–1.0) prepared by the standard ceramic technique have been studied. Single phase cubic structure is confirmed by X-ray diffractometer. This result demonstrates that the samples are homogeneous, and the sharp peaks reveal that the samples are in crystalline form. The lattice parameter ‘a’ and average grain diameter ‘D’ increase with increasing Mn2+ ion substitution. The saturation magnetization and the experimental magnetic moment are found to increase with manganese up to x=0.5 and then tends to decrease for x>0.5. The increase in magnetic moment with manganese is attributed to Neel's two sublattice model according to which the magnetic moment is the vector sum of lattice magnetic moment. The decrease in magnetization for x>0.5 obeys the Yafet–Kittel (Y–K) model. The increase in Y–K angles for x≥0.5 indicates the increased favor for triangle spin arrangements on B-sites. This suggests the existence of canted spin structure in the ferrite system with higher content of Mn. Hystersis loops were measured. The initial permeability μi was measured as a function of temperature. ► The XRD patterns reveal the spinel structure of the prepared ferrites. ► The lattice parameter ‘a’ and average grain diameter ‘D’ increase with increasing Mn2+ ion substitution. ► The experimental magnetic moment increases with manganese content up to x=0.5 and then tend to decrease for x>0.5. ► The increase in magnetic moment with manganese is attributed to Neel's two sublattice model. ► The decrease in magnetization for x>0.5 obeys Yafet–Kittel (Y–K) model.