Electrical and dielectric characteristics of magnetic ceramics of Mn _1−x Ni _x Fe ₂ O ₄ spinel nanoferrites

Ceramics materials of the class of spinel nanoferrites of Mn1−xNixFe2O4 (x = 0·00, 0·025, 0·50, 0·75 and 1·00) of 13–25 nm particle sizes have been investigated for their electrical and dielectric characteristics. The dc electrical resistivity was measured and found to decrease with an increase in x to follow the Verwey mechanism because of the increase in electron hopping between the Fe2+ tetrahedral site (A site) and the Fe3+ octahedral site (B site). In addition, the resistivity of ferrites was observed to decrease with an increase in temperature, confirming their semiconductor characteristics. The dielectric constant and the dielectric loss factor were found to decrease as the frequency increased, following the Maxwell–Wagner interfacial type of polarisation. The study of the electrical properties of the prepared ferrites suggests their usefulness in important applications in electronic devices in reducing power losses due to an increase in conductivity caused by the increment in Ni concentrations in various electronic circuitries, such as those in computers and transformer coils.