Dielectric Relaxation and Room Temperature Magnetoresistance Under Low Magnetic Field in Polypyrrole-BaTiO3 Hybrid Nanocomposites

Abstract

BaTiO3 and polypyrrole (ppy)-BaTiO3 hybrid nanocomposites have been synthesized by chemical oxidative polymerization method. Microstructure and crystallinity of the hybrids are studied using field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD) technique. As prepared BaTiO3 are rod-like, while PPY-BaTiO3 nanocomposites indicate the formation of bulging agglomerates of spherical particles with various sizes (40–50 nm). Dielectric constants at room temperature of the composites have largely enhanced (up to 6000). The hybrid composite shows grain boundary relaxation in the frequency range (42 Hz-5 MHz). Three dimensional (3D) variable range hopping (VRH) with high localization of charge carriers (Mott temperature ≈ 8725658 K) is observed in the temperature dependent conductivity evaluation of composite system. Negative magnetorestance (MR ≈ 4.3%) has been measured at 1 T. The observed MR is explained with the help of forward interference model.