Structural and electrical studies of Mn-Ni mixed nanoferrites

Mn-Ni mixed spinel nanoferrites with varying nickel concentration (0.1, 0.2, 0.3, 0.4, and 0.5) were prepared by co-precipitation method. The spinel phase formation was confirmed by XRD and FTIR. Microstructure and compositional analysis were done by SEM and EDX respectively. Room temperature dielectric properties, resistivity and AC-conductivity were studied. The nanoferrites possess a very high dielectric constant. Dielectric loss tangent decreases with increase in nickel concentration and a broad peak appears for higher nickel concentration (0.2, 0.3, 0.4 and 0.5). Variation in DC-resistivity with nickel concentration goes in agreement with the variation of dielectric constant. Frequency variation of AC-conductivity for different nickel concentration shows dispersion at higher frequencies for different Ni concentration. Conduction mechanism has been explained on the basis of hopping electron model of ferrites.