Electrical properties of Zr~(4+)-substituted Mg-Zn ferrites

摘要

Electrical conductivity and thermoelectric power measurements were carried out on Zn_xMg_(1-x+y)Zr_xFe_(2-2y)O_4 ferrites, with x = 0.1, 0.2, 0.3, 0.4, 0.5 and y = 0.01, 0.03, 0.05, 0.07. Temperature variation of d.c. resistivity exhibits a break at Curie temperature. The variation of Seebeck coefficient from room temperature to 700 K reveals n-type conductivity for the entire system. The activation energies from mobility data agree well with those obtained from resistivity experiments. Fermi energies F_F(o) calculated from thermoelectric power data are in good agreement with activation energies in the Fermi region. However the slightly larger values of ΔE_1 than E_FV(o) indicate that part of the energy is associated with the generation of electrons and the other part is associated with the hopping of electrons between equivalent sites.