Role of spin disorder in magnetic and EMI shielding properties of Fe3O4/C/PPy core/shell composites

Novel core/shell Fe3O4/C/polypyrrole (PPy) composites were prepared via facile hydrothermal and chemical oxidative polymerization method. The obtained Fe3O4/C/PPy exhibits a dual core-shell structure in which an intermediate carbon layer provides excellent electrical connectivity between Fe3O4 nanoparticles and PPy polymer. Further, these trilaminar core/shell composites were investigated for EMI shielding material to prevent EMI pollution. The excellent EMI shielding efficiency (> 28) dB was attained for Fe3O4/C:PPy (2:8 wt/wt) at thickness 0.8 mm which is mainly governed by absorption. Additional evidence of superior EMI absorption performance is the magnetic property of Fe3O4/C:PPy composites. It was observed that magnetic properties of Fe3O4/C:PPy composites highly depend on the content and thickness of the shell which influences the spin motion of Fe3O4 nanoparticles. Thus, it is anticipated that spin motion plays a decisive role in EMI shielding performance of Fe3O4/C/PPy composites.