Investigation of structural, magnetic and electrical properties of aluminum substituted Co-Mg ferrite

The effect of nonmagnetic Al3+ substitution on the structural, morphological, magnetic, and dielectric characteristics of Co0.5Mg0.5AlxFe2-xO4 ferrite nanoparticles synthesized using the co-precipitation method was investigated. All samples were found to have a single-phase cubic spinel by X-ray diffraction. The decrease in crystallite size from 55 to 29 nm with Al3+ substitution validated the materials nano-crystalline formation. The infrared spectrum exhibits two distinct absorption bands matching to the spinel structure as well as two extra absorption bands and a shoulder between 360 and 265 cm(-1). The DSC exothermic peaks around 440 degrees C may be attributed to the phase shift of the prepared samples from amorphous to the crystalline state. The TEM results were used to investigate the sample shape and quantify particle size demonstrating that increasing the Al3+ content induces a decrease in particle size. The VSM technique revealed a decrease in magnetic properties which was attributable to an increase in nonmagnetic Al3+ ions. The magnetic permeability is found to rise with increasing Al3+ content as the anisotropy constant decreases. Dielectric characteristics were investigated at room temperature in the frequency range of 0.1 Hz-20 MHz. The presence of polaron type conduction in the prepared samples was confirmed by the ac conductivity. These produced nanoparticles dielectric characteristics demonstrate their utility in high-frequency device development applications and electronic device production.