The Hall coefficient of dilute palladium and platinum alloys

Abstract

The low field Hall coefficient R has been measured at room temperature and 4.2K in a number of dilute Pt-Pd, Pt-Au, Pt-Ir, Pt-Os, Pd-Pt, Pd-Ag, Pd-Rh and Pd-Ru alloys. For several palladium alloys the authors have also measured the temperature variation of R over the complete temperature range. At 4.2K the value of R for each system attains a 'characteristic' value R0 which is, in every case, more negative than the value of R at room temperature in the corresponding parent metal, with the spread in the value of R0 rather greater for the palladium alloys. For the alloys based on platinum in which details of the Fermi surface are well established the results are interpreted on the basis of a two band model with constant relaxation times over the two major regions of the Fermi surface. The model indicates that the contributions to the electrical conductivity from electrons and holes are roughly comparable.