A Study of the Magnetic Domains of Isolated Fine Particles of Ba Ferrite

Abstract

Isolated Ba ferrite particles are prepared by the conventional powder metallurgical method, and the magnetic domains of about 200 particles 0.5 to 5 µm in size are investigated by the colloid-SEM method (the Bitter method using a scanning electron microscope). The relationship between the three-dimensional sizes of Ba ferrite particles and their magnetic domain states is clarified. It is found that the critical size of isolated single-domain particles of Ba ferrite is somewhat larger than the value calculated using the magnetic domain theory.