Synthesis and characterization of L-histidine coated Fe3O4 nanocomposite

Abstract

L-histidine coated iron oxide nanoparticles (HCIO) have been synthesized in one pot in the presence of L-histidine. The characterization and analysis results revealed that magnetic nanoparticles are maghemite (or magnetite) and L-histidine is covalently bonded to the nanoparticle surface via carboxyl groups. Thermal analysis revealed that magnetic nanoparticles showed catalytic effect that caused an early degradation/decomposition of the L-histidine capping. Single crystalline nature of iron oxide NPs was confirmed by near spherical morphology assessed by TEM, particle size calculated from TEM analysis and crystallite size calculated from XRD analysis. Magnetic measurements reveal the superparamagnetic character of the nanoparticles, hence the nanocomposite. The ac conductivity showed a temperature dependent behavior at low frequencies and temperature independent behavior at high frequencies which is an indication of ionic conductivity. The dc conductivity of the nanocomposites is found to obey the Arrhenius plot with activation energy of 0.934eV. Analysis of electrical modulus and dielectric permittivity functions suggest that ionic and polymer segmental motions are strongly coupled in the nanocomposite. Keywords: L-histidine, magnetic nanoparticles, magnetic property, conductivity.