Synthesis and Magnetic Properties of Sr0.65−xCaxLa0.35Fe11.32Co0.28O18.435 Hexaferrites Prepared by Solid-State Reaction Method

M-type hexaferrite Sr_0.65-xCa_xLa_0.35Fe_11.32Co_0.28O_18.435 (0 ≤ x ≤ 0.45) magnetic powder and magnets were prepared according to the solid-state reaction method. The phase compositions of the calcined powder samples were characterized by X-ray diffraction. There is a single magnetoplumbite phase in the calcined magnetic powder with the increase of x from 0 to 0.45. The micrographs of the sintered magnets were observed by a field emission scanning electron microscopy. The sintered magnets have formed the perfect hexagonal structure and the particles are distributed evenly. The influence of calcium content on magnetic properties of the magnets was studied systematically. The magnetic properties [including B_r, H_cj, H_cb and (BH)_max] of the magnets first increase with x from 0 to 0.20, and then, begin to decrease when x continues to increase. The magnetic properties of the magnet at x = 0.20 reach the maximum values.