Structural, spectral, magnetic, and electrical properties of Gd-Co-co-substituted M-type Ca-Sr hexaferrites synthesized by the ceramic method

Gd-Co-co-substituted M-type Ca-Sr hexaferrites with nominal compositions Ca0.40Sr0.60-xGdxFe12.00-xCoxO19 (0.00x0.32) were prepared using the standard ceramic method. The particle size of obtained hexaferrite powders is between 2 and 5 mu m. These hexaferrites were characterized by thermal analyzer (TG-DSC), X-ray diffractometer (XRD), Fourier transformer infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometer (VSM), and resistivity testing system. XRD patterns showed that the single M-type hexaferrite phase was obtained only if Gd-Co content (x)0.16. FE-SEM micrographs indicated that the grains were platelet-like shapes. The saturation magnetization (M-s) and remanent magnetization (M-r) decreased with increasing Gd-Co content (x) from 0.00 to 0.32. The coercivity (H-c) first increased with Gd-Co content (x) from 0.00 to 0.24, and then decreased when Gd-Co content (x)0.24. The DC electrical resistivity decreased with increasing Gd-Co content (x) from 0.00 to 0.32.