Ferroelectric, dielectric, and EMI attenuation characteristics of BaFe2O4/MWCNTs/epoxy nanocomposites

Abstract

ABSTRACT This study reports the synthesis of barium-ferrite (BaFe2O4) particles by co-precipitation method, which is employed to prepare BaFe2O4/multiwall carbon nanotubes (MWCNTs)/epoxy nanocomposites. Furthermore, the structural properties, ferroelectric and dielectric properties, and electromagnetic attenuation properties are studied. The role of varying concentrations of BaFe2O4, frequency, and temperature on dielectric behavior is studied. In the presence of applied field, dielectric constant enhances as a result of interfacial polarization with increasing BaFe2O4 concentration. The permittivity is highest at low frequency and decreased with increasing frequency. With temperature, initially, dielectric constant increases and then decreases as a result of charge accumulation at interfaces and leads to interfacial polarization as confirmed by ferroelectric behavior. Here, BaFe2O4/MWCNTs/epoxy composite (with 40 phr BFO, where phr denotes parts per hundred) exhibited the highest value of saturation polarization (PS) ~0.31 µC/cm2 and low value of remanent polarization (Pr), that is ~0.009 µC/cm2. Moreover, composites exhibited high electromagnetic interference (EMI) shielding effectiveness (SE) of nearly 19 dB for 40 phr BaFe2O4 concentration at 11.3 GHz. Here, the reflection-dominated SE is ~1.06 dB and absorption-dominated SE is about 18.67 dB, which dominates the total SE. The absorption-dominant behavior is depicted by the BaFe2O4/MWCNTs/epoxy nanocomposites in EMI shielding as further conferred in the text.