Effect of mechanical activation and ferritization on the phase composition of W-type hexaferrites obtained by the method of self-propagating high-temperature synthesis

Abstract

Hexagonal oxide W-type ferrimagnetic powders (BaCo0.7Zn1,3Fe16O27) are obtained by the method of self-propagating high-temperature synthesis (SHS) in combination with preliminary or further mechanochemical activation in a high-energy unit and ferritization. The data on the phase composition, structural parameters and fundamental magnetic properties of synthesized ferrimagnetic used to create effective absorbers of electromagnetic radiation in the range of natural ferrimagnetic resonance frequencies are presented. Dispersion of the SHS product is found to significantly affects the value of the effective constant of magnetic crystallographic anisotropy. To explain this fact, a model that considers the contribution to magnetic anisotropy from magnetoelastic interaction and a perturbed near-surface layer, which are additive, is used. SHS with further mechanical activation and fine grinding shows that the mechanical treatment of the SHS product in a high-energy unit (planetary mill) is a way of controlling the magnetic properties of oxide hexagonal ferrimagnetic and, in this sense, affects like chemical doping