Fabrication of NiS nanoparticles by Microwave technique and its effectiveness in electromagnetic interference shielding

Abstract In recent years, the widespread use of high frequency devices has led to a major problem termed as electromagnetic (EM) interference or electromagnetic pollution. Electromagnetic (EM) radiation can adversely affect the performance of other electronic devices and pose potential risks to human health. Consequently, there is a growing demand for EM wave shielding materials that are lightweight, exhibit broad absorption bandwidth, high absorption efficiency, and excellent thermal stability. Semiconductor metal sulphides have attracted a lot of attention nowadays as electromagnetic shielding device because of its high dielectric properties, low cost and high thermal stability. In comparison to metal oxides metal sulphides exhibit better conductivity and better dielectric loss. We have synthesized Nickel Sulphide (NiS) nanoparticles by the microwave technique. X ray diffraction of the samples proved that that they were phase pure. Field emission scanning electron microscope image proved the morphology of the particles were nearly cubic. The Hysteresis loop of the sample proved the weak ferromagnetic nature. EM wave absorption of the NiS sample is studied in the wide frequency range of 1–20 GHz. It shows an excellent reflection loss of −59.75 dB with an absorber thickness of only 4.46 mm at only 20 wt% filler content. The effective absorption bandwidth obtained was 5.62 GHz which is a broad range ideally suitable for EM absorber. The best impedance matching |Z in /Z 0 | ~ 1 was obtained at 11.2 GHz. This study proves the utility of NiS nanoparticles as highly effective electromagnetic shielding device.