Electrical Conductivity and Seebeck Effect in Ni0.80Fe2.20O4

Abstract

Electrical conductivity and Seebeck effect have been measured as functions of temperature on single-crystal samples of ${\mathrm{Ni}}_{0.80}$ ${\mathrm{Fe}}_{2.20}$ ${\mathrm{O}}_4$. A thermal hysteresis has been observed in the conductivity but not in the Seebeck effect. This suggests that the hysteresis involves the charge carrier transfer process but not the production of carriers. The activation energy associated with the transfer process is estimated to be 0.10 ev in the high-temperature state and 0.06 ev in the low-temperature state.