the generation of an electric field in metals and semiconductors in the presence of a temperature gradient and an external magnetic field that is perpendicular to this gradient. This effect is classified as one of the thermomagnetic effects; it was discovered in 1886 by W. Nernst and A. von Ettingshausen. A distinction is made between (1) the longitudinal Nernst-Ettingshausen effect, which is the change in the thermoelectromotive force under the action of a magnetic field perpendicular to the temperature gradient, and (2) the transverse Nernst-Ettingshausen effect (often called the Nernst effect), which is the appearance of an electromotive force in a direction perpendicular to both the magnetic field and the temperature gradient. The Nernst-Ettingshausen effect depends on the relationship between the relaxation time and the energy (or velocity) of current carriers when the current carriers interact with the lattice; therefore, the effect is sensitive to the scattering mechanism of the current carriers. Study of the Nernst-Ettingshausen effect can yield information on the mobility of current carriers and on the relaxation time.
E. M. EPSHTEIN