OBSERVATION OF THE EXPONENTIAL TEMPERATURE DEPENDENCE OF THE TUNGSTEN SINGLE CRYSTAL MAGNETORESISTIVITY (PEIERLS' EXPONENT)

The transverse magnetoresistivity of ultrapure tungsten single crystals in Corbino disk form was measured in the temperature interval 4.2–50 K in magnetic fields up to 14 T. The exponential temperature dependence of the electroconductivity, predicted by Peierls and caused by the intersheet electron-phonon Umklapp processes, is discovered in the magnetoconductivity. When the intersheet Umklapp processes are "frozen-out" the temperature dependence of the magnetoconductivity is a power function.