Influence of Tb substitution on electromagnetic and microwave absorption properties of barium hexaferrites

Abstract

Rare earth element Tb substituted hexaferrite Ba1−xTbxCo2Fe16O27 (where x = 0·00–0·25) are synthesised by solid state reaction method. The samples present single W type phase and homogenous grain size. The substitution of Tb3+ decreases the lattice parameter c and cell volume of ferrite. The imaginary part of complex permittivity ϵ″ shows a tendency of decrease with the increasing Tb content. The imaginary part of complex permeability μ″ increases with the increasing Tb content in the frequency range of 0–12 GHz. The magnetic loss tan δm of sample, with Tb content x = 0·25, increases about 0·20 after being substituted by Tb3+. As a result, the microwave absorption properties of Tb substituted ferrites are enhanced in the investigated frequency. The X-ray photoelectron spectroscopy results indicate that the Fe exists as mixed valence state of Fe(II) and Fe(III), and the valence state of Co ions is unchanged as Co2+ after the substitution of Ba2+ with Tb3+ in hexaferrites.