Study of manganese spinel ferrite/polypyrole composites for high-frequency applications

The MnFe₂O₄ spinel ferrites and polypyrrole were prepared using the sol-gel route. The nanocomposites were characterized by using different analytical tools, including XRD (X-ray Diffraction), an impedance analyzer, a VSM (vibrating sample magnetometer), and DC resistivity. The XRD pattern of the ferrites shows the FCC cubic structure of prepared nanocomposites. The increased ferrite content in nanocomposites leads to lower peak intensity and narrow peaks. The crystallite size was increased from 18 to 51 nm and the lattice constant reduced from 8.42 Å to 8.26 Å. The DC resistivity was determined by using the two-probe method of the prepared composite materials. The activation energy was increased from 0.20 to 0.39 eV. The magnetic properties of nanocomposites were determined by applying the magnetic field from \(\pm\) $\pm$ 2 KOe. The ferrites are soft and exhibit ferromagnetic behavior demonstrated by the thin magnetic loops. Numerous characteristics, including coercivity H_c, saturation magnetization M_s and remanence magnetization M_r, were computed within a magnetic loop. The M_s of the polypyrrole was found at 11 emu/g and it increased when manganese ferrites were added to the PPy from 29 to 47 emu/g. The dielectric loss and dielectric constant were decreased with the addition of the ferrites in PPy. The improvement of all parameters indicates that the prepared PF4 could be well-suited for high-frequency applications.