High-frequency magnetic and dielectric properties of Ba1.5Sr1.5Co1Zn1Fe23O41 hexaferrites with Bi2O3 additives

Abstract

Ba1.5Sr1.5Co1Zn1Fe23O41 hexaferrites added with x wt% Bi2O3 were successfully prepared, and their phase composition, microstructure, and high-frequency magnetic and dielectric properties were investigated. The results show that the Bi2O3 additive leads to the formation of the W-type ferrite phase and a subsequent increase in its proportion, which affects the magnetic and dielectric properties of Z-type hexaferrites. This effect can be explained by the effective medium theory. Furthermore, Bi2O3 additives improve the compactness and reduces the grain size. The permeability and permittivity of the samples decrease, but the magnetic and dielectric losses are successfully reduced. For x = 1.5 wt%, the samples have a similar permeability and permittivity, a large miniaturization factor (∼18), a cut-off frequency of about 0.9 GHz, and considerably reduced magnetic and dielectric losses. An appropriate amount of Bi2O3 additive improves numerous properties of the Ba1.5Sr1.5Co1Zn1Fe23O41 ferrite, making it a more suitable material for high-frequency miniaturized antennas.