مشخصات پژوهش

عنوان	Multilayer Structures of a Zn0.5Ni0.5Fe2O4-Reduced Graphene Oxide/PVDF Nanocomposite for Tunable and Highly Efficient Microwave Absorbers
نوع پژوهش	مقاله چاپ‌شده در مجلات علمی
کلیدواژه‌ها	poly(vinylidene fluoride), reduced graphene oxide, Zn0.5 Ni 0.5Fe2 O4 , multilayer structure, electromagnetic interference shielding, absorption
چکیده	Attenuating electromagnetic waves with an absorption-dominant mechanism is still an arduous challenge, despite the recent progress in fabricating advanced electromagnetic interference (EMI) shields. In this study, EMI shielding materials with an outstanding absorption performance were developed. As such, in the first step, we report a practical method for synthesizing magnetic Zn0.5 Ni0.5 Fe 2O 4 (ZnNiFe) nanoparticles. The magnetic hysteresis loop reveals that the synthesized magnetic nanoparticles are superparamagnetic with a saturation magnetization of 75.8 emu/g. Thereafter, we propose an EMI absorber using a multilayer assembly of polyvinylidene fluoride sheets containing low concentrations of reduced graphene oxide (rGO) and ZnNiFe. It is shown that the EMI shielding effectiveness increases from 23.93 to 29.05 dB, and the shielding by reflection decreases from 6.5 to 0.5 dB. This happens as the number of layers increases from two to nine at a fixed total thickness of 1.8 mm and filler loadings of 1 wt % rGO and 5 wt % ZnNiFe. More importantly, the nine-layer sample shows an absorption coefficient of A = 0.91, which translated into absorption of more than 91% of the incident wave. To the best of our knowledge, this is the highest ever reported absorbance for a polymer-based EMI shield. It is hypothesized that the superior absorbance of the nine-layer structure originates from (1) multiple internal reflections inside the shield due to the presence of numerous conductive layers and (2) supermagnetic properties of ZnNiFe nanoparticles, leading to enhanced magnetic loss.
پژوهشگران	محمد ارجمند (نفر ششم به بعد)، فرهاد احمدی جوکانی (نفر پنجم)، احمدرضا غفارخواه (نفر چهارم)، فرهاد رحمانی چیانه (نفر سوم)، میلاد کامکار (نفر دوم)، ماجد امینی (نفر اول)