The conduction mechanism of Li-Ga ferrite

Gallium substituted lithium-ferrite having the general formula Li0.5Fe2.5-xGaxO4 with 0.0 <= x <= 0.5 in steps of 0.1 were synthesized by the standard ceramic technique. The variation of DC and AC conductivities with temperature have been reported in a wide range of temperature from room temperature 293 K up to 1023 K in static air. AC measurements were carried out in a wide range of frequencies from 100 Hz up to 1 MHz. The values of activation energies for the compositions containing gallium approximately is twice the activation energy of x = 0. The electron mobility in Li0.5Fe2.5O4 shows an activation energy of 0.36 eV, while the activation energy of Li-Ga ferrites are ranging from 0.64 to 0.77 eV. These values are due to a narrow-band conduction mechanism and a formation of small polaron. (C) 2008 Elsevier B.V. All rights reserved.