The thermoelectric power of the system NiFe204-Fe304

Abstract

Measurements are reported of the resistivity and the thermoelectric power as a function of temperature for nickel-iron ferrites. The thermoelectric power shows a transition from a temperature independent to a temperature activated region. The results are broadly in agreement with the Jonker hopping model but some disagreement with the accepted simple theory is found. A 2-energy-level model is proposed for the Fe²⁺ ions; this removes most, though not all, discrepancies between predicted and experimental results.