Magnetic properties of Ba-ferrite powders prepared by surfactant assisted ball milling

Abstract

Magnetic properties of Ba-ferrite powders processed by a novel method: surfactant assisted low energy ball milling, are discussed. By using cationic and anionic surfactants at pH values above and below the point of zero charge of the oxide surface, some remarkable changes in magnetic properties of the milled material are produced. Vibrating sample magnetometry (VSM) and ferromagnetic resonance are applied for sample evaluation. Directly after milling the particles are in the submicron range with a narrow size distribution. By application of an annealing procedure in air or vacuum to prepared powders changes were observed. Final annealing in air of the samples annealed first in vacuum produces Ba-ferrite powder with m/sub o/M/sub s/ and H/sub c/ values in a remarkably broad range 0.457-0.564 T, and 136-195 kA/M respectively.< >