Metallic Nano to Micro Size Particles Embedded in High Dielectric Ferrites for Effective EMI shielding.

Abstract

In this study, the conventional auto-combustion sol-gel technique was used to synthesize Mg-substituted Zn ferrite with the chemical formula MgxZn1-xFe2O4 (x = 0.1, 0.25, 0.50, 0.75, and 0.90). The substitutional effect of Mg ion was studied on the structural, dielectric, and electromagnetic interference (EMI) properties of Mg-ZnFe2O4 ferrite and characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), Impedance analyzer (IA) and vector network analysis (VNA). XRD analysis has confirmed the spinel cubic phase pattern with an average crystallite size of 67 to 39 nm. It has been observed that the substitution of Mg significantly affects structural characteristics (such as lattice constant, x-ray density, bulk density, porosity density, etc.) of synthesized Mg- Zn ferrite. Scanning electron microscope examined the surface morphology of the powder. The increasing amount of Mg2+ improved the dielectric, and EMI properties of Mg-ZnFe2O4 ferrite. EMI studies reflect that the absorption properties are better than other samples for the zinc ferrite sample with maximum (0.9) amount of Mg in the sample. Using ball milling, Al incorporation into MgxZn1-xFe2O4 ((x = 0.1, 0.5, 1%) was achieved successfully. Further using the space charge polarization model of Maxwell-Wagner Al/MgxZn1-xFe2O4 characteristics like dielectric were explained. The frequency dependent dielectric constant and the dielectric losses were the primary elements of the electrical analysis. Overall EMI shielding results are in well agreement with dielectric properties. EMI absorption performance is enhanced up to SEA= -29.3 dB at 2.9 GHz for 0.5Al/Mg0.9Zn0.1Fe2O4