Simulation of DC-hopping conduction in spinel ferrites using free electron gas model

In this work, DC-hopping conductivity in spinel ferrites is simulated using free electron gas model. This simulation is performed by two substitutions: first, the mean free time in theory of independent electron approximation with the tunneling time of electrons between two adjacent octahedral sites in spinel structure and, second, the number density of free electrons with the number density of tunneled electrons in the hopping process. The barrier's width is obtained from the geometry of spinel lattice and its height from the electrostatic potential of two adjacent oxygen cation. The results of this simulation were compared with experimental values of DC-hopping conductivity for different compositions of zinc, nickel and manganese ferrites. A reasonable agreement was observed in a wide range of temperatures. (c) 2007 Elsevier B. V. All rights reserved.