Synthesis and characterization of BaGd_0.075Fe_1.925O₄/polypyrrole composites for EMI shielding

Sol–gel route was used to synthesize the spinel ferrites BaGd_0.075Fe_1.925O₄. The polymers and spinel ferrites were combined to prepare nano-composites. Techniques such as XRD (X-ray diffraction), vibrating-sample magnetometer (VSM), dielectric properties and DC (direct current) resistivity were used to characterize the composites. The nano-composites which contained more ferrite concentration have more peak intensity and width. Based on the Debye relaxation model and Koop’s phenomenological hypothesis, it can be seen that the relative permittivity dropped as the frequency was increased. The inclusion of ferrite increased the DC resistivity and decreased the dielectric loss. The hysteresis curve demonstrated that nano-composites are ferromagnetic in nature. By adding ferrite to the polypyrrole matrix, the magnetic properties like as coercivity (36 Oe to 330 Oe) and saturation magnetization (32 emu/g to 59 emu/g) increased. The sample (PF3) with low dielectric loss and high resistivity suggests that it may be the potentially ideal for EMI shielding.