Observation of rhombohedral CoFe2O4 phase in Co-Mg co-doped SrFe12O19 hexaferrite

A series of SrFe12-2x(CoMg)2xO19 (x = 0.0-1.0) samples were prepared using microwave-hydrothermal method at 200 degrees C/60 min. The Rietveld refined X-ray diffraction patterns show the existence of CoFe2O4 (rhombohedral) and SrFe12O19 (hexagonal) phases. It is observed that with increasing x, the (113) plane intensity is increased but (107) and (114) corresponds to hexaferrite decreased. The phase percentage of CoFe2O4 is consistent with doping x, which confirms that the phases of CoFe2O4 and SrFe12O19 are both present in the material. The fourier transform infrared spectrum shows the two absorption bands, 443 cm- 1 , and 601 cm- 1 . It is observed that agglomeration of grains increased with x, resulting to non-uniform distribution of grains. The coercivity drastically decreased from 2384 (x = 0.0) to 438 Oe (x = 0.8), indicating a soft magnetic nature. The minimum reflection loss of - 23.86 dB is observed for x = 0.4 at a frequency 9.66 GHz. Therefore, the present investigated samples are useful for microwave applications.