دانلود Influence of calcium content on the structural and magnetic properties of Sr0.70−xCaxLa0.30Fe11.75Zn0.25O19 hexagonal ferrites

Abstract

Hexagonal ferrite Sr _0.70xCa_xLa _0.30 Fe _11.75 Zn _0.25 O₁₉ (0≤x≤0.70) magnetic powder and magnets were prepared by the ceramic process. The phase characterization of the calcined powders was investigated by X-ray diffraction. There is a single magnetoplumbite phase in the magnetic powders with x from 0 to 0.60 and for the magnetic powders with x of 0.70, the α-Fe₂O₃ phase is observed. The morphology of the sintered magnets was examined by a field emission scanning electron microscopy. The magnets have formed the hexagonal structures and the particles are distributed evenly. Magnetic properties of the calcined powders and sintered magnets were measured by a vibrating sample magnetometer and a magnetic properties test instrument, respectively. The saturation magnetization, remanent magnetization and coercivity of the magnetic powders increase with the increase of x from 0 to 0.2, and then begin to decrease when x˃0.2. The remanence, intrinsic coercivity, magnetic induction coercivity and maximum energy product of the sintered magnets first increase with x from 0 to 0.20, and then, start to decrease when x continues to increase. The magnetic properties of the sintered magnet at x=0.20 reach the maximum values.