ANISOTROPY OF THE ELECTRON-PHONON UMKLAPP PROCESSES AND GALVANOMAGNETIC PROPERTIES OF TUNGSTEN SINGLE-CRYSTALS IN HIGH MAGNETIC-FIELDS

In the temperature range of 4.2-50 K and magnetic fields to 140 kOe the temperature behaivor is measured for the galvanomagnetic coefficients of tungsten single crystals with rho(293)/rho(4.2) to 95,000 in two magnetic field directions along the <110> and <111> axes. The magnetoresistance measurements are performed in the Corbino disk-shaped samples and Hall-power is done in the rectangle-shaped ones. The temperature behavior of the magnetoconductivity is shown to have an exponential temperature-dependent contribution due to the intersheet electron-phonon Umklapp processes. When this mechanism of the conduction electron scattering dominates, the Hall resistance experiences the strong temperature power-law variations.