The impact of the iron content on the microstructure and magnetic properties of M-type ferrites Sr_(0.45)Ca_(0.25)La_(0.30)Fe_xCo_(0.25)O_(19)

摘要

M-type ferrite Sr_(0.45)Ca_(0.25)La_(0.30)Fe_xCo_(0.25)O_(19) (10.45 ≤x≤ 12.25) magnetic powders and magnets were prepared by a conventional ceramic method. Phase components of the magnetic powders were examined by X-ray diffraction. There is only the magnetoplumbite-type phase in magnetic powders with iron content (x) ranging from 10.45 to 11.65. When iron content (x)≥ 11.85, hematite (α-Fe_2O_3) phase begins to occur. The morphology of the magnets was investigated by a field emission scanning electron microscopy. The magnets have formed a hexagonal structure and the particles are distributed evenly. Magnetic properties of the magnets and magnetic powders were measured by a permanent magnetic measuring equipment and a vibrating sample magnetometer, respectively. The remanence, intrinsic coercivity, magnetic induction coercivity, and maximum energy product first increase with iron content (x) of range 10.45-11.05 and then decrease when iron content (x) continues to increase. The magnetic properties at x = 11.05 reach the maximum values.