Poly(m-toluidine)/Ba_0.8La_0.2Fe₁₀Al₂O₁₉ (PMT/BLFA) and poly(m-toluidine-co-aniline)/ Ba_0.8La_0.2Fe₁₀Al₂O₁₉ (PMT-co-PANI/BLFA) composites were prepared by in-situ polymerization. The structure and morphology of the samples were characterized by TG-DTA, XRD, FT-IR, UV-Vis, TEM and SEM, and the magnetic and dielectric properties of samples were measured by impedance/materials analyzer and vibrating sample magnetometer (VSM). The results indicated that the BLFA particles were coated by the copolymer (polymer) chains to form the composites which had an obvious core/shell structure. The thermal stability of composites was higher than that of copolymer (polymer). The magnetization intensity of the composites was related to BLFA content, while the coercivity had little change|PMT/BLFA and PMT-co-PANI/BLFA composites had excellent magnetic loss properties and dielectric loss properties because of the synergistic effect between dielectric and magnetic medium. Hence, they can be recommended as candidates for electromagnetic wave absorption and shielding materials.

Key words: in situ polymerization, magnetic properties, dielectric property, loss