Charge transport mechanism and the effect of poling on the current-voltagecharacteristics of conducting polyaniline-BaTiO3 composites

Conducting polyaniline-barium titinate (PANI-BaTiO3) composites have been s ynthesized by 'in situ' deposition technique by placing the fine grade powd er of BaTiO3 (prepared by conventional sol-gel technique) in the polymeriza tion reaction mixture of aniline - finally yielding the Polyaniline-BaTiO3 composites. The charge transport process in these composites have been stud ied by sandwiching the pellets of these composites between the silver and p latinum electrodes. It presumably suggests presence of a nonlinear space ch arge controlled charge transport process. Also, a large hysteresis in the I -V characteristics of these composites has been observed which also support s the space charge controlled conduction. The samples were poled by applyin g a constant voltage for a fixed time and the I-V characteristics were trac ed before and after poling. Some striking differences have been observed in the I-V characteristics before and after poling. These have been explained on the basis of creation of an internal electric field due to poling which in turn opposes the externally applied electric field. (C) 1999 Elsevier S cience S.A. All rights reserved.