Structural Elucidation with Improved Dielectric and Magnetic Properties of Sol–Gel Synthesized Cr³⁺ Substituted M-Type Sr²⁺ Hexaferrites

Hexaferrites of Sr_1-xCr_xFe₁₂O₁₉ with x = (0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were fabricated by citrate sol–gel technique. Characterization of grown samples such as structural and morphological analysis was performed by XRD and Scanning Electron Microscopy (SEM). Effect of Cr³⁺ incorporation on the electrical, structural and dielectric properties of Sr_1-xCr_xFe₁₂O₁₉ x = (0.0, 0.1, 0.2, 0.3, 0.4, 0.5) was reported. Confirmation of single phase M-type hexaferrite structure was carried out by the x-ray diffraction analysis. Lattice parameters have been reported to boost as the content of Cr³⁺ rises, which is due to the ionic size of the cation involved. SEM analysis indicates the decrease in grain size with the substitution of Cr³⁺. The dielectric constant and ac conductivity represent increasing behavior, while dielectric and tan loss indicate decreasing behavior with the increase in frequency and with Cr³⁺ content. The increasing decreasing trend of saturation magnetization was observed, and it is due to the different site occupancy of iron at different crystallographic sites. The coercivity values (6.64-6.72 KOe) of all samples were found to be in the range of M-type hexaferrites. These dielectric parameters values are appropriate for different applications in high-frequency devices such as modulators, phase shifters and also in longitudinal recording media.