Zhanggao Le

Lanthanum and Neodymium Doped Barium Ferrite-TiO₂/MCNTs/poly(3-methyl thiophene) Composites with Nest Structures: Preparation, Characterization and Electromagnetic Microwave Absorption Properties.

We report herein the synthesis of a novel nest structured electromagnetic composite through in-situ chemical polymerization of 3-methyl thiophene (3MT) in the presence of the BaFe11.92(LaNd)0.04O19-TiO2 (BFTO) nanoparticles and MCNTs. As an absorbing material, the BFTO/MCNTs/P3MT/wax composites were prepared at various loadings of BFTO/MCNTs/P3MT (0.2:0.10:1.0 ~ 0.2:0.30:1.0), and they exhibited strong microwave absorption properties in the range of 1.0–18 GHz. When the loading of BFTO/MCNTs/P3MT is 0.2:0.30:1.0, the composite has a strongest absorbing peak at 11.04 GHz, and achieves a maximum absorbing value of −21.56 dB. The absorbing peak position moves to higher frequencies with the increase of MCNTs content. The mechanism for microwave absorption of these composites has been explained in detail.

Preparation and properties of La-doped barium ferrite/poly (3-methylthiophene) composites

La-doped barium ferrite/poly(3-methylthiophene)(LB/P3MTH) composites have been successfully synthesized by in suit chemical polymerization with ferrite chloride (FeCl3) as an initiator. The composites structure is investigated by X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy, and the morphology of samples is observed by transmission electron microscopy (TEM). Magnetic properties of the composites are tested by vibrating sample magnetometer. XRD analysis shows that La3+ has got into the lattice of Ba-ferrite and replaces the Ba2+ and that the best La3+ amount of La-doped Ba-ferrite is not more than 0.08. La-doped Ba-ferrite particles are coated with poly (3-methylthiophene). TEM image reveals that La-doped Ba-ferrite particles have spherical morphology and are agglomerated due to the coated polymer. P3MTH covers the ferrite surface and has crystallite boundaries, which influences the composites’ physical and chemical properties.