Impacts of Ni-Co substitution on the structural, magnetic and dielectric properties of magnesium nano-ferrites fabricated by micro-emulsion method

Magnesium ferrite (MgFe2O4) nano-structures doped with Ni-Co at magnesium and iron sites respectively were fabricated by the micro-emulsion method and characterized by the X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and dielectric measurements. The analysis of XRD patterns confirm the single phase spinel structure and the crystallite size calculated by Scherer's formula lies in the range of 15-26 nm. The spectral studies elucidate the characteristic feature of spinel phase. The real and imaginary parts of dielectric constant and dielectric loss exhibit peaking behavior. The dielectric properties have been explained on the basis of Debye-type relaxation phenomenon in accordance with Koop's phenomenological theory. The increase in the tendency of saturation magnetization is consistent with the enhancement of crystallinity. The crystallite size is small enough to obtain considerable signal to noise ratio in the recording media. The optimized dielectric and magnetic parameters suggest that the material with composition Mg-0.6 Ni-0.4 Co-0.4 Fe1.6O4 may be used for applications in recording media and microwave devices. (c) 2013 Elsevier B.V. All rights reserved.