Influence of Mg2+ substitution on structural, electrical polarization, and magnetic properties of Sr-based R-type hexagonal ferrites

Substitutional effects of Mg2+ proceeding the structural, Fourier-transform infrared spectroscopy, scanning electron microscopy, and vibrating sample magnetometer characteristics of Sr1-xMgxMn2Fe4O11 R-type hexaferrite were systematically investigated for different concentrations (x = 0, 0.25, 0.75, 1.0). Sol-gel technique was adopted to fabricate the material. X-ray diffraction analysis confirmed samples exhibit a single-phase structure of MgMn2Fe4O11. Lattice parameters (a and c) and V (unit cell volume) decreased with increasing Mg concentration. Also, a rise in dislocation density was observed, while crystallite size varied. FTIR spectra further corroborated the single-phase hexagonal structure of the manufactured samples. The electric polarization (P-E) loops demonstrated that saturation and Pr remanent polarization increased with Mg substitution, while lossy behavior decreased. Magnetic measurements revealed that substituting Mg2+ directed toward an initial escalation in saturation magnetization, retentivity, and coercivity, followed by a subsequent decline. Furthermore, VSM analysis indicated that all samples exhibited a combination of ferrimagnetic and paramagnetic behavior.