MAGNETIC-PROPERTIES OF BARIUM FERRITE PARTICLES WITH FE3O4 OVERCOAT

Superparamagnetic Fe3O4 fine particles were introduced onto the surfac e of barium ferrite particles. The method was to coat the barium ferri te particles with a mixed solution of Fe3+ and Fe2+ first at certain c oncentrations, followed by addition of NaOH(aq). The results showed th at the coercivity of barium ferrite could be lowered greatly while a h igh saturation magnetization value was sustained. It indicates that th ere exists an interaction between barium ferrite and Fe3O4 fine partic les and this interaction is a matter of interface and may not bear dep endency on whether chemical bonding is formed between them.