The thermopower of NiCr- and PtRh-alloys – a new view

Abstract

Abstract For the interpretation of the Seebeck coefficient S ( T ) S(T) of transition metal alloys where one or both of the alloy partners develop a spin moment, so far spincluster models in connection with the standard Boltzmann-Fermi theory S ( T ) ∼ T S(T)\sim T have been adopted. However, this interpretation suffers from some obvious inconsistencies, in particular with NiCr-alloys. In this contribution we try to alleviate these inconsistencies by implementing the recently proposed correlated electron thermopower terms which appear in the framework of Fermi-Boltzmann statistics when it is applied to Stoner-Slater intraatomic exchange (J) split electronic states. For both NiCr- and PtRh-alloys we recover the typical electron correlation term of the thermoelectric power, S D {S_{D}} , while former inconsistencies can be removed. As NiCr and PtRh-alloys are often used in high temperature sensing because of their stability, this new interpretation of the thermoelectric power may help to develop a better calibration and compositional choice of alloy-based thermocouples.