Morphology tuned dielectric, electrical, impedance, relaxation metrics of Co–Mg doped strontium ferrite, and their computational modeling

Sol-gel technique was used to develop M-type hexaferrites SrCo_xMg_xFe_12-2xO₁₉. The impact of doping of Co–Mg is analyzed on structural, dielectric, and electrical properties. The analysis was done in the frequency range of 150 Hz to 2 MHz. X-ray diffraction (XRD) analysis was performed for the determination of phase and structure of the prepared ferrites. The obtained results indicated the presence of an M-type hexagonal structure. The inclusion of Co–Mg caused a decrement in the crystallite size from 30.48 to 17.22 nm. The morphological analysis was performed using scanning electron microscopy (SEM), which reveals the formation of needle-shaped platelet structures. The doping had a non-monotonical effect on the dielectric constant and loss tangent. All the prepared compositions showed non-Debye-type relaxation for electric modulus. The increase in doping of Co–Mg caused a reduction in relaxation time. From the impedance spectroscopy, it was observed that both grains and grain boundaries affected the electrical characteristics.