Hexagonal ferrites Sr1-xLaxFe11.80Cu0.20O19 magnetic powders and magnets were prepared by the solid state reaction. The phase compositions of the magnetic powders were identified by X-ray diffraction. There is a single magnetoplumbite phase in the magnetic powders with x from 0.12 to 0.32, and for the magnetic powders with x ≥ 0.36, the LaFeO3 phase is observed. The microstructures of the magnets were investigated by a field emission scanning electron microscopy. The magnets are formed of hexagonal-shaped crystals and the particles are distributed homogeneously. The magnetic properties of the magnets were measured by a magnetic properties test instrument. The remanence of the magnets increases with x from 0.12 to 0.40. However, the intrinsic coercivity, magnetic induction coercivity and maximum energy product of the magnets first increase with x from 0.12 to 0.24, and then begin to decrease when x continues to increase.

Keywords: M-type hexaferrites, La content, La-Cu substitution, Magnetic properties.