Magnetic and microwave absorption properties of Fe/TiO2 nanocomposites prepared by template electrodeposition

Uniform, high filling Fe/TiO2 core/shell nanowire arrays with different aspect ratio were fabricated by a two-step controllable electrodeposition technique using anodic aluminum oxide (AAO) membrane as template. Amorphous structure of TiO2 nanotubes and polycrystalline nature of Fe nanowires were confirmed by transmission electron microscopy (TEM). It was demonstrated experimentally that the arrays with high aspect ratio exhibited more obvious magnetic anisotropy. Based on the experimental results, microwave magnetic loss of the arrays with high aspect ratio was attributed to eddy-current loss and hysteresis loss. However, microwave magnetic loss of the arrays with low aspect ratio originated from natural ferromagnetic resonance (NFR), which led to the shift of resonance frequency to the GHz range. The bandwidth (RL ≤ 10 dB) of the arrays with high aspect ratio was obtained in the frequency of 10.8-14.9 GHz, indicating excellent microwave absorption performance of Fe/TiO2 core/shell nanowire arrays at high frequency.