Facilitating enhanced microwave absorption properties of barium hexaferrite/polyaniline composites based on tunable interfacial polarization by rare earth doping

Barium hexaferrite (BaM)/polyaniline (PANI) is a typical microwave absorbing composite that effectively integrates magnetic and electric losses. To enhance its microwave absorption properties, a facile method based on rare earth element doping was explored; the effects of rare earth elements on the microstructures and properties of both BaM nanopowders and the subsequent BaM/PANI composites were investigated. The use of rare earth elements, including La, Nd, and Ce, in the BaM particles alleviated the constraints of the electric polarization in PANI near the surfaces of the BaM particles; this resulted in more electric polarization at the interfaces of the Re-BaM and PANI phases. This provided a versatile way to enhance the absorption efficiency, expand the absorption frequency range, and reduce the thickness. The La-BaM/PANI composite demonstrated a maximum reflection loss of approximately − 63.6 dB at 7.76 GHz with an optimum thickness of 3.28 mm. The effective absorption range of the Nd-BaM/PANI composite was 4.72 GHz. Ce-BaM/PANI composites released a relatively broad effective frequency range of approximately 3.88 GHz and a small thickness of 1.58 mm.