Thermoelectric power properties of Zn substituted Cu–Ga spinel ferrites

Composition and temperature dependence of dc conductivity and Seebeck coefficient for Cu 1−xZn xGa 0.5Fe 1.5O 4 (0.0 ≤ × ≤ 0.5) are discussed. Thermoelectric power studies of this ferrite series are investigated from room temperature to well beyond the Curie temperature by the differential method. The Seebeck coefficient φ is found to be positive for compositions with x ≤ 0.2 indicating that these ferrites behave as p-type semiconductors, while compositions with x ≥ 0.3 show n-type semiconductors with φ negative. Results of the dc conductivity display semiconducting behavior of these materials. Transition temperatures obtained from both studies are in good agreement and was found to be decreased linearly with Zn content. Some physical properties of the samples such as density and porosity are also discussed. The obtained results are discussed in the light of the interactions over the metal sites in the spinel unit cell.