The ferrofluid dynamics theory is applied to thermodiffusive problems in
magnetic fluids in the presence of magnetic fields. The analytical form for the
magnetic part of the chemical potential and the most general expression of the
mass flux are given. By employing these results to experiments, global Soret
coefficients in agreement with measurements are determined. Also an estimate
for a hitherto unknown transport coefficient is made.Comment: 7 pages, 2 figure