Substitution Effects of Calcium to Microstructures and Magnetic Properties of Sr0·70–xCaxLa0·30Fe11·72Cu0·28O19hexaferrites

Abstract The hexaferrite Sr0·70–xCaxLa0·30Fe11·72Cu0·28O19 (0≤x≤0·70) magnetic powders and magnets were synthesised by the ceramic process. The phase compositions of the magnetic powders were investigated using X-ray diffraction. X-ray diffraction patterns show that the hexagonal single phase is obtained in all samples. The morphology of the magnets was investigated using a field emission scanning electron microscopy. The magnets are formed of hexagonal shaped crystals and the particles are distributed evenly. The bulk density of the magnets decreases with calcium content (x) from 0 to 0·70. Magnetic properties of the magnets were measured using a permanent magnetic measure equipment. The remanence, intrinsic coercivity, magnetic induction coercivity and maximum energy product of the magnets first increase with x from 0 to 0·20, and then decrease when x continues to increase. The magnetic properties of the magnet at x = 0·20 reach the maximum values.