Synthesis and electromagnetic properties of BaFe11.92(LaNd)0.04O19/titanium dioxide composites

Doped BaFe11.92(LaNd)(0.04)O-19/titanium dioxide composites have been prepared by the gel-precursor self-propagating combustion process. The characterization of the composites are performed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Differential thermal analysis-thermo gravimetry (DTA-TG), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and network analyzer. Both XRD and FT-IR indicate that the doped BaFe11.92(LaNd)(0.04)O-19/titanium dioxide composites are successfully synthesized and there are some interactions between BaFe11.92(-LaNd)(0.04)O-19 and titanium dioxide. DTA-TG analysis of BaFe11.92(LaNd)(0.04)O-19/titanium dioxide composites shows that the composite gel decomposition process mainly includes two stages: the first stage is the crystallized water and the residual moisture evaporation: the second stage is the nitrate and citric acid decomposition reaction. SEM demonstrates that the doped BaFe11.92(LaNd)(0.04)O-19/titanium dioxide solid solution has formed. The magnetic parameters indicate that the electromagnetic properties of the composites could be well adjusted by the mass ratio of BaFe11.92(LaNd)(0.04)O-19 and titanium dioxide. When the mass ratio of BaFe11.92(LaNd)(0.04)O-19 and titanium dioxide is 4:5, the composites have the best magnetic loss. The composites with the mass ratio 6:5 of BaFe11.92(-LaNd)(0.04)O-19 and titanium dioxide. BaFe11.92(LaNd)(0.04)O-19 and titanium dioxide possess good dielectric loss. The introduction of titanium dioxide enhances the dielectric loss and widens the frequency bands. The composites will be promising microwave absorption materials with wide frequency band. (C) 2013 Elsevier Ltd. All rights reserved.