Effect of Chromium Doping on the Structure and Properties of Ba0.5Sr0.5Fe12 – xCrxO19 Hexaferrites

Ba0.5Sr0.5Fe12 – xCrxO19 (x = 0.5–3) hexaferrites are synthesized by a solid-phase reaction method. The influence of substitution of chromium ions (Cr3+) for iron ions (Fe3+) on the structure and morphology of the materials is studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All synthesized samples are found to be single-phase and to have a magnetoplumbite structure. When the chromium content increases, the unit cell parameters (a, c, V) decrease monotonically, which is explained by the smaller ionic radius of Cr3+ compared to Fe3+. The substitution is found to decrease the Curie temperature (TC) due to a weakening of the superexchange interaction. The investigation of dielectric properties demonstrates that chromium doping improves dielectric characteristics: the permittivity increases in the low-frequency region and the dielectric losses decrease significantly.