Preparation and Microwave Absorption Properties of the Fe/TiO2/Al2O3 Composites

Abstract

To reduce the imbalance of impedance matching between the magnetic metal nanowires and free space, Fe/TiO2 core/shell nanowire arrays with different diameters were fabricated in the templates of anodic aluminum oxide membranes by electrodeposition. The influences of the microstructure on the microwave absorption properties of the Fe/TiO2/Al2O3 composites were studied by the transmission/reflection waveguide method. It was demonstrated experimentally that both the interfacial polarization and the diameter of the Fe/TiO2 core/shell nanowires have critical effects on the microwave absorption properties. We also investigated the angle dependence of the microwave absorption properties. Due to the interfacial polarization and associated relaxation, the Fe/TiO2/Al2O3 composites exhibited optimal microwave absorption properties when microwave propagation direction was accordant with the axis of the nanowires. Finally, we managed to obtain an optimal reflection loss of below [Formula: see text]10[Formula: see text]dB (90% absorption) over 10.2–14.8[Formula: see text]GHz, with a thickness of 3.0[Formula: see text]mm and the minimum value of [Formula: see text]39.4[Formula: see text]dB at 11.7[Formula: see text]GHz.