Dielectric relaxation and conduction mechanism of cobalt ferrite nanoparticles

The electric transport behavior of nano cobalt ferrite was studied in details within frequency window of 100 Hz and 1 MHz in the range of temperature of 25-200 degrees C. No grain relaxation was observed whereas interfaces (grain boundary and electrode surface contact) became the dominant conduction regions. Both ac and dc conduction mechanism was investigated thoroughly. Overlapping of large polaron tunneling (OLPT) mechanism was found to be responsible for ac conduction process. The value obtained for mobility (10(-10) cm(2)/Vs) of charge carriers indicated the possible small polaron hopping for dc conduction process. The dc resistivity data was fitted with Mott and Davis model and the derived parameters confirmed the dc conduction of non-adiabatic nature which was due to small polaron hopping in nano cobalt ferrite. (C) 2014 Elsevier B.V. All rights reserved.