Ferromagnetic and microwave absorption properties of copper oxide-carbon fiber composites

This paper reports that copper oxide-carbon fiber (CuO/CF) composites are synthesized by annealing copper/carbon fibers in air. Interestingly, CuO/CF shows ferromagnetic at room temperature, and the strongest RL of CuO/CF composite is −29.6 dB at 7.8 GHz, and the corresponding thickness is only 1.8 mm. The strong absorption of CuO/CF composites (1.0–4.0 mm in thickness) is less than −10 dB (>90%) over the range of 2.7–15.9 GHz and −20 dB (>99%) over the range of 3.0–9.4 GHz, respectively. The CuO/CF composites are believed to be ideal for making lightweight, strong absorption and wide-frequency microwave absorbing materials.