Methods for measurement of the isothermal Nernst coefficient

When a temperature gradient is present along a semiconductor in a perpendicular magnetic field, an electric field (and accompanying voltage) can be induced in the transverse direction; this is called the Nernst effect. The thermomagnetic material property known as the Nernst coefficient is of interest because it can reveal useful information about the charge carrier scattering mechanism(s) in the material. Due to the presence of other thermomagnetic and thermoelectric effects that may be present under non-isothermal conditions in the transverse direction, the value obtained in the measurement of the Nernst coefficient can differ from its isothermal value, impacting the interpretation of experimental data. Since the currently available literature offers limited insights, we have begun an evaluation of different approaches for experimentally measuring the isothermal Nernst coefficient. In this presentation, we present preliminary results from a comparison of quasi-adiabatic and quasi-isothermal Nernst coefficient measurements. We also discuss how the use of non-isothermal Nernst coefficient may impact the results in the analysis and interpretation of experimental thermomagnetic transport properties data.