Effect of hopping rate and jump length of hopping electrons on the conductivity and dielectric properties of Co-Cd ferrite

The cobalt cadmium ferrite has an n-type conductivity. As the Cd addition (x) increases, the hopping rate increases and so the conductivity increases up to x = 0.5. A sudden decrease in the hopping rate occurs above x = 0.5 due to the decrease of Co2+ ions on octahedral sites. Above x = 0.7, the hopping rate increases again and the conductivity increases. As the hopping length increases the conductivity decreases, i.e. conductivity is inversely proportional to hopping length, but is directly proportional to the hopping rate of electrons. As the ferrous ions increase on octahedral sites, the conductivity increases and the jumping length decreases leading to the increase of dielectric constant. (C) 2001 Elsevier Science B.V. All rights reserved.