Polymer–spinel ferrite composite containing nickel, magnesium, and nickel–magnesium ions: Structural, magnetic, electrical, and thermal stability properties

Abstract

AbstractFirstly, three different nano ferrites (MgFe2O4, NiFe2O4, and Ni0.5Mg0.5Fe2O4) were synthesized using a combustion method. Secondly, polyaniline composites containing small amounts of those nano ferrites were prepared using in situ chemical polymerization method. Ferrite samples were characterized using X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT‐IR) analyses. XRD analysis of ferrites exhibited well‐resolved broad peaks, which confirm the polycrystalline and mono‐phasic nature. FT‐IR confirmed the spinel structure of these ferrites. Polymer nano ferrites composites were also characterized using XRD, FT‐IR, thermal analysis (TG and DTA), and transmission electron microscope (TEM). Also, electrical (AC conductivity, dielectric constant, dielectric loss, and complex impedance) and magnetic properties were investigated for all nano composite samples. XRD analysis confirmed the formation of polymer nano composites. Moreover, the absorption bands of polyaniline were shifted in the presence of the three different ferrites, confirming the presence of interactions between the different phases in all composites. Additionally, different thermal stability behavior of nano composite samples was observed, which may be attributed to the nano ferrite type and the physical interactions nature with polymer matrix. The sample containing nano magnesium ferrite showed the core–shell structure by TEM. The same sample exhibited the highest values of both AC conductivity (1.01 × 10−4 ohm−1 cm−1) and magnetization saturation (3.38 emu/g) at room temperature. In comparison with other similar composites containing large amounts of the same ferrite, the investigated sample showed a good magnetization saturation value and thermal stability behavior.