Magnetic Field Dependence of the Thermoelectric Power of Iron

Abstract

The thermoelectric power of iron exhibits a broad maximum of about 17 µV/K near 200 K. The relatively high temperature of this maxim and its dependence on alloying and cold work argue against phonon drag as the mechanism responsible for this peak. Recently, MacInnes and Schröder proposed that this peak derives from anisotropic (scew) scattering due to spin–orbit coupling, which may be simulated by a large effective transverse magnetic field. Their calculations, which reproduce experimental observations quite well, are based on an expression derived by Sondheimer that is valid for an ideal two-band model. According to this model and the suggestion of MacInnes and Schröder, the thermoèlectric power of iron should be strongly influenced by domain alignment. Measurements of the dependence of the thermoelectric power of iron in transverse and longitudinal magnetic fields reported here yield results contrary to the predictions of that model.