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 CoFe2O4 nanoparticles to synthesize the CoFe2O4/CNTs nanocomposites by the solvothermal method. The phase structure, morphology, magnetic properties and microwave absorption performance of the as-prepared CoFe2O4/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 CoFe2O4 nanoparticles decorating on the surface of CNTs increased with the solvothermal temperature. CoFe2O4/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 CoFe2O4/CNTs nanocomposites increased with the solvothermal temperature up to -15.7 dB for S-26 with the bandwidth of 2.5 GHz.