Structural,dielectric and magnetic manifestation in BaM/PEEK nanocomposite for X band shielding blocks

The microwave absorber nanocomposites consisting of substituted M-type hexaferrite Ba_0.8Gd_0.2Fe_11.5Co_0.5O₁₉ and polyetheretherketone (PEEK) have been investigated for X-band applications. Composites with hexaferrite to PEEK ratios 5:0, 4:1, 3:2, 2:3, 1:4, 0:5 have been synthesized by a micro-emulsion method. XRD results confirm the hexagonal structure of the hexaferrite with average crystallite size up to 37.2 nm. Magnetic properties reveal that saturation magnetization M_s increases whereas coercivity H_c decreases by increasing the ferrite content in the composites. Complex permittivity and permeability have been tailored with ferrite content in the X-band. The dielectric constant reduces from 5.3 to 3.25 while permeability increases up to 1.37 with increasing ferrite concentrations. The microwave results show the minimum reflection loss of ?10.79 dB for composite with 80% ferrite.