Thermoelectric Power in Ruthenates: Dominant Role of the Spin Degeneracy Term

摘要

The Seebeck coefficients of several ruthenates which structures derive from the perovskite, have been measured up to 800K. All the values above 300K are found to be in the range +25μV.K{sup}(-1) to +35μV.K{sup}(-1), with a very weak dependence on both T absolute value and electrical resistivity. This demonstrates that S at high T depends mainly on the spin degeneracy term of the modified Heikes formula. The insensitivity of thermopower to the chemical doping confirms the applicability of the model. The present study also shows the good properties of ruthenates as thermoelectric p-type oxides for high T energy conversion.