Title :
Enhancement of coercivity in Co modified γ-Fe2O 3 particles by adsorption of ions
Author :
Ohmori, Masahiro ; Matsumoto, Kazuyoshi
Author_Institution :
Central Res. Lab., Showa Denko K.K., Chiba, Japan
fDate :
7/1/1994 12:00:00 AM
Abstract :
Several ions were adsorbed on the surface of acicular Co modified γ-Fe2O3 particles by a surface treatment in their wash process. Coercivity of prepared particles was increased from 580 to 640 Oe and saturated magnetization was decreased from 78.7 to 77.5 emu/g with the amount of adsorbed ion after the treatment with calcium, magnesium and silicon. On the other hand, aluminum,a trivalent ion did not lead to an enhancement in coercivity with the same treatment. Dependence on ionic valence was observed in this Hc behavior. Several ideas were discussed to explain the He enhancement, and possible enhancement mechanisms for this behavior have been evaluated
Keywords :
adsorption; cobalt; coercive force; ferrites; magnetic properties of fine particles; magnetic recording; surface treatment; Fe2O3:Co; acicular particles; coercivity; enhancement mechanisms; high density recording media; ion adsorption; ionic valence; saturated magnetization; surface treatment; wash process; Calcium; Cobalt; Coercive force; Costs; Magnetic materials; Magnetic recording; Magnetic separation; Magnetization; Production; Surface treatment;
Journal_Title :
Magnetics, IEEE Transactions on
