Hall Effects, Resistivity, and Thermopower in Fe and Fe1−xNix for x=0 to 0.2

Abstract

Measurements were made of the ordinary and extraordinary Hall effects and the electrical resistivity in a series of iron-nickel alloys from pure iron to 20% nickel in iron, in the temperature range from 77°K to room temperature. The thermopower of the same alloys was measured in the range from 200 to 300°K. The ordinary Hall, thermopower, and resistivity data indicate that hole conduction is important for pure iron, and that as nickel is added electron conduction becomes more important. The location and shape of the Fermi surface is estimated from the results of an energy-band calculation, using a rigid-band model. The results are in agreement with increasing electron and decreasing hole contributions as nickel is added to iron. Both the data and the energy-band results seem to lead to a complicated multiband picture at low nickel concentrations and an approach towards single-, nearly spherical-, band conduction at 20% nickel. The temperature and composition dependence of the ordinary Hall coefficients are accounted for qualitatively by estimates of the anisotropy of the relaxation time and of the effect of impurity scattering on the relaxation time. The extraordinary Hall coefficient is fitted by a number of models based upon theories by various authors. Fairly good agreement with experiment is obtained over a wide range of composition and temperature, but with no clear preference for any of the theories.