Electromagnetic wave absorption characteristics of Mg-Ti substituted Ba-hexaferrite

In the present work, doped barium ferrite with the composition of BaFe9Mg 1.5Ti1.5O19 was prepared via solid state method. The crystalline structure, particles size, magnetic and microwave absorption properties were investigated by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer and Vector Network Analyzer. The results showed that samples with the magnetoplumbite structures with widely distributed particle sizes have been formed. The coercive force and resonance absorption frequency of samples were sharply reduced by increasing the amount of Mg2+ and Ti4+ dopants. The reflection loss was studied as a function of frequency and thickness of samples. The results showed a broadband characteristic with the minimum absorption of - 10 dB in the range of 12 to 18 GHz for all thicknesses of the sample. The composite sample with matching thickness of 2.2 mm had wide bandwidth absorption in the frequency range of 13 to 17 GHz with reflection losses less than -20 dB. Therefore, BaFe9Mg 1.5Ti1.5O19 is a suitable absorptive material with a high attenuation and broad bandwidth at microwave frequencies. (c) 2007 Elsevier B.V. All rights reserved.