ELECTRICAL-CONDUCTIVITY AND THERMOELECTRIC-POWER OF LITHIUM-CADMIUM FERRITES

The electrical conductivity (σ) and thermoelectric power (Q) of polycrystalline lithiumcadmium ferrites having the chemical formula Li0.5–x/2CdxFe2.5–x/2O4 where (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) have been investigated as a function of temperature. Lithium‐cadmium ferrite with x = 0.4 is found to possess minimum electrical conductivity and lowest Seebeck coefficient. Plots of log (σT) versus 103T are almost linear and have shown a transition near the Curie temperature except in the case of cadmium ferrite. The Seebeck coefficient is negative for all the compositions showing that these ferrites behave as n‐type semiconductors. The values of charge carrier concentration and mobility have also been computed. The properties of cadmium‐substituted lithium ferrites have been correlated with those of zinc‐substituted lithium ferrites, cadmium and zinc being two non‐magnetic divalent ions occupying essentially tetrahedral A sites when substituted in ferrites. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA