Electrical and magnetic behaviour of nanostructured MgFe2O4 spinel ferrite

Nanostructured MgFe2O4 spinel has been synthesized with various grain sizes ranging from 72 to 19 nm using ceramic method and followed by high-energy ball milling. The observed electrical conductivity decreases with grain size is mainly due to the size effect than the cation distribution which is clearly evident by in-field Mössbauer measurement. The saturation magnetization of the 72 nm grain size sample has been enhanced and it is about 39% larger than that of their bulk (micron size particle). The observed increase in the coercivity of the milled sample is due to the smaller crystalline size, increase in the grain boundary volume and also due to surface anisotropy of increasing number of ions on the surface.