The low-temperature, high-field Nernst-Ettingshausen coefficient of Al

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Abstract
The high field Nernst-Ettingshausen coefficient of a pure polycrystalline foil of Al from 1.8K to 5K has been measured. The experimental value of the diffusion component of this coefficient yields a transport heat capacity gamma t which is the same as the experimental electronic heat capacity gamma c with a probable uncertainty of less than 3%. This result demonstrates that the electron-phonon renormalisation is identical for both the specific heat and Nernst-Ettingshausen coefficients to within an uncertainty of 10%. The experimental phonon-drag component of the Nernst-Ettingshausen coefficient is positive and varies approximately as T3 in the temperature range studied. Both the sign and temperature variation are taken as evidence of the presence of substantial electron-phonon Umklapp scattering.