Novel three phase polyvinyl alcohol (PVA)-nanographite (GNP) -Pb(ZrTi)O3 (PZT) composites with high dielectric permittivity.

Novel three phase composites were prepared by embedding nanographite (GNP) and lead zircon ate titanate (Pb(ZrTi)O3; PZT) into the polyvinyl alcohol (PVA) matrix via solution casting technique. The structural analysis was carried out by using X-ray diffraction technique, which indicated the tetragonal structure of Pb(ZrTi)O3 (PZT). The frequency dependences of dielectric, electrical and ferroelectric properties of the PVA-PZT-GNP composites on different volume fractions of GNP were investigated. The percolation theory was used to progress the dielectric and electrical performance of PVA-PZT-GNP composite. It was observed that the PVA-PZT-GNP composite showed insulator-conductor transition with percolation threshold of 5 vol% of nanographite. The dielectric permittivity of PVA-PZT-GNP composite was achieved as high as ≈117 at 100 Hz at percolation threshold, which was about 17 and 5 times higher than that of pure PVA and PVA-PZT composite, respectively. The ferroelectric hysteresis loop investigation indicated that the three phase composites exhibited much higher electric polarization than that of two phase PVA-PZT composite systems. [ABSTRACT FROM AUTHOR]