Shielding performance of MnxNi0.8–xZn0.2Fe2O4 (0.1≤x≤0.7) for electromagnetic interference (EMI) in X-band frequency

Abstract

A series of MnxNi0.8–xZn0.2Fe2O4 (0.1≤x≤0.7) nanoferrites were prepared by sol-gel auto combustion method. The TGA-DSC studies revealed the weight loss up to 700 °C and after no weight loss was found confirming the complete ferrite phase. Therefore, the as-burnt samples subjected to conventional sintering at 900 °C for 2h. The traces of XRD patterns revealed that formation of ferrite phase co-existed with secondary phases. The complex permittivity and permeability of present ferrite systems are found to be dependent of Mn2+ ion concentration. The real part of dielectric constant (ε′) for the all compositions are in the range of 5.184–6.951 at 8.2 GHz while it is 5.269–7.663 at 12.4 GHz. The values of ε′ at 8.2 GHz are slightly lower than the values at 12.4 GHz. The imaginary part of dielectric constant (ε″) was found to be in the range of 0.046–0.315 for all compositions over the entire range of X-band frequency (8.2–12.4 GHz). Compared to the variation of ε′, the variation of ε″ is more disorder. The number of semicircles in Cole-Cole plots is a witness of multiple di-electric relaxations of EM energy dissipation. The real part of magnetic permeability (μ′) is increasing, while imaginary part of magnetic permeability (μ″ ) is decreasing for all compositions as frequency is increasing from 8.2 to 12.4 GHz. Compared to the other ferrite compositions, the ferrite with low content of Mn2+ i.e. Mn0.1Ni0.7Zn0.2Fe2O4 ferrite system has higher value of μ″ and seems to be invariant over the entire X-band frequency range. The total effective shielding (SET) for all compositions is found to be in the range 37–12 dB. The highest values of SET 37 dB at 8.2 GHz and 28 dB at 12.4 GHz were reported for the ferrite composition Mn0.1Ni0.7Zn0.2Fe2O4. The shielding studies revealed that Mn–Ni–Zn ferrite systems are effectively suppressing electromagnetic interference (EMI) in X-band frequency. Comparatively, the ferrite system Mn0.1Ni0.7Zn0.2Fe2O4 is useful for the fabrication of EMI suppressor.