Synthesis and electromagnetic properties of BaFe_11.92(LaNd)_0.04O₁₉/titanium dioxide composites

Graphical abstract: Due to combining different functions and characteristics of individual materials, hybrid nanocomposite materials can strengthen their applications. Magnetic-conductive nanocomposites are the promising materials with electromagnetic loss, which have synergetic behavior between magnetic and conductive materials. It is the first time to report the synthesis of BaFe_11.92(LaNd)_0.04O₁₉/titanium dioxide (BF/TD) composites by the gel-precursor self-propagating combustion process. The influence of mass ratio of BF and TD on the electromagnetic properties of BaFe_11.92(LaNd)_0.04O₁₉/titanium dioxide composites was studied. The tgδ_μ and tgδ_ε of BF–TD composites. - Highlights: • It is the first time to report BaFe_11.92(LaNd)_0.04O₁₉/titanium dioxide composites. • The composites are prepared by the gel-precursor self-propagating combustion. • The electromagnetic properties could be adjusted by the mass ratio of BF and TD. • The introduction of TD enhances the dielectric loss and widens the frequency bands. • BF/TD composites will be microwave absorption materials with wide frequency band. - Abstract: Doped BaFe_11.92(LaNd)_0.04O₁₉/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 BaFe_11.92(LaNd)_0.04O₁₉/titanium dioxide composites are successfully synthesized and there are some interactions between BaFe_11.92(LaNd)_0.04O₁₉ and titanium dioxide. DTA–TG analysis of BaFe_11.92(LaNd)_0.04O₁₉/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 BaFe_11.92(LaNd)_0.04O₁₉/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 BaFe_11.92(LaNd)_0.04O₁₉ and titanium dioxide. When the mass ratio of BaFe_11.92(LaNd)_0.04O₁₉ and titanium dioxide is 4:5, the composites have the best magnetic loss. The composites with the mass ratio 6:5 of BaFe_11.92(LaNd)_0.04O₁₉ and titanium dioxide. BaFe_11.92(LaNd)_0.04O₁₉ 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