Microwave Absorption and Magnetic Properties of Cobalt Ferrites/Carbon Nanotubes Nanocomposites

Owing to the unique microstructure and the excellent dielectric properties, carbon nanotubes (CNTs) were decorated with CoFe 2 O 4 nanoparticles to synthesize the CoFe 2 O 4 /CNTs nanocomposites by the solvothermal method. The phase structure, morphology, magnetic properties and microwave absorption performance of the as-prepared CoFe 2 O 4 /CNTs were characterized and discussed by X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). All results indicated that the diameter of CoFe 2 O 4 nanoparticles decorating on the surface of CNTs increased with the solvothermal temperature. CoFe 2 O 4 /CNTs prepared at 180°C, 200°C and 220°C exhibited superparamagnetism, while the other samples presented ferromagnetism at room temperature. And with the increasing solvothermal temperature, the saturation magnetization and coercivity increased up to 72 emu/g and 2000 Oe for the sample prepared at 260°C (S-26). And the reflection loss of CoFe 2 O 4 /CNTs nanocomposites increased with the solvothermal temperature up to -15.7 dB for S-26 with the bandwidth of 2.5 GHz.