Field-Dependent Thermopower of Dilute Magnetic Alloys

The thermopower of dilute magnetic alloys in an external magnetic field is calculated using the perturbation series for the $s-d$ exchange Hamiltonian. We explicitly include terms proportional to the spin polarization of the impurities. In low fields and in the absence of interactions between the impurities, we expect the thermopower to vary as the square of the impurity magnetization. In high fields we find a $\frac{1}{H}$ behavior which should persist even with interactions between the impurities. Comparison is made with the only available data, on $\mathrm{Au}\mathrm{Fe}$ alloys, and the encouraging agreement suggests that new experiments on the field-dependent thermopower would be most interesting.