Magnetoresistive polyaniline–silicon carbide metacomposites: plasma frequency determination and high magnetic field sensitivity

Abstract

The Drude model modified by Debye relaxation time was introduced to determine the plasma frequency (ω_p) in the surface initiated polymerization (SIP) synthesized β-silicon carbide (β-SiC)/polyaniline (PANI) metacomposites. The calculated plasma frequency for these metacomposites with different loadings of β-SiC nanoparticles was ranging from 6.11 × 10⁴ to 1.53 × 10⁵ rad s⁻¹. The relationship between the negative permittivity and plasma frequency indicates the existence of switching frequency, at which the permittivity was changed from negative to positive. More interestingly, the synthesized non-magnetic metacomposites, observed to follow the 3-dimensional (3-D) Mott variable range hopping (VRH) electrical conduction mechanism, demonstrated high positive magnetoresistance (MR) values of up to 57.48% and high MR sensitivity at low magnetic field regimes.