Preparation, magnetic properties and microwave absorption of Zr–Zn–Co substituted strontium hexaferrite and its nanocomposite with polyaniline

Resumo

M-type strontium hexaferrite substituted by Zr⁴⁺, Zn²⁺, and Co²⁺ was firstly synthesized by a sol-gel auto combustion method. Then the polyaniline/hexaferrite nanocomposite with 20 wt % hexaferrite was prepared by in situ polymerization method. The structure, morphology, and composition of substituted hexaferrite, polyaniline and their composition were investigated by using XRD, FTIR, TGA-DSC, UV-Vis spectroscopy, and FESEM techniques. The results showed that M-type hexaferrite nanoparticles were formed and nanoparticles were effectively coated by polyaniline chains. The magnetic properties of samples were measured by the vibrating sample magnetometer (VSM). The saturation magnetization (M_s), magnetic remanence (M_r), and coercivity (Hc) of composite are lower than those of pure hexaferrite. The microwave absorption properties of samples were measured by vector network analyzer (VNA). The results indicated that the minimum reflection loss (RL) of composite is–20 dB at 10.1 GHz and its bandwidth with more than 90% absorption is up to 3.5 GHz which has covered the overall X-band.