Ferrites with excellent electrical and magnetic properties have widely used in industrial applications such as permanent magnets, microwave absorbers and magnetic memory media due to their low price and chemical stability. Among them, M-type hexaferri...
Ferrites with excellent electrical and magnetic properties have widely used in industrial applications such as permanent magnets, microwave absorbers and magnetic memory media due to their low price and chemical stability. Among them, M-type hexaferrites (MFe<sub>12</sub>O<sub>19</sub>, M=Sr, Pb, Ba) with magnetoplumbite are known to have a high saturation magnetization of 70 emu/g and low coercive field (<sup>3+</sup> ions with other suitable ions, such as Al<sup>3+</sup>, Cr<sup>3+</sup>, Ga<sup>3+</sup>, and replacing Sr<sup>2+</sup>ions with Ca<sup>2+</sup> ions. Especially, M-type hexagonal ferrite substituted Al3+ ions for octahedral Fe3+ sites has very large coercivities, leading to lattice contraction of the unit cell. In this study, we synthesized hexaferrite particles (Sr<sub>(1-x/12)</sub>Ca<sub>(x/12)</sub>Fe<sub>12-x</sub>Al<sub>x</sub>O<sub>19</sub>(x=4-6) with a coercivity over 20kOe via spray drying process. Thus, Sr-hexaferrite substituted with Al-Ca would be a good alternative for electromagnetic wave absorbers.