Investigations of microwave Faraday rotation in single crystals ofnhyphen;type germanium at liquidhyphen;N2temperature

摘要

Freehyphen;carrier Faraday rotation measurements have been performed at liquidhyphen;N2temperature in single crystals ofnhyphen;type germanium using 24.0hyphen;GHz radiation in order to investigate experimentally the nature of its variation withBover a wider range of mgr;Bthan possible from the roomhyphen;temperature study. The investigations have been extended withBalong all the three principal orientations, viz., 001, 111, and 110 ofnhyphen;Ge crystals, in order to examine experimentally the validity of the predictions of the Donovanhyphen;Webster theory regarding anisotropy in the Faraday rotation with respect to magnetic field orientations at the liquidhyphen;N2temperature. The measured rotation at this low temperature has been found, in general, to be less than that predicted by the above theory. The discrepancy between the experiment and theory disappears on the inclusion of the contribution of ionized impurity scattering in the Donovanhyphen;Webster theory, which takes into account lattice scattering only. The measurements have been further carried out in samples of different resistivities in order to study the effect of increase of conductivity of the sample on the nature of variations of thgr; withBat liquidhyphen;N2temperature. The values of the lattice and the impurity mobilities in different samples have been determined. The variation of observed Verdet constant with conductivity fornhyphen;Ge at liquidhyphen;N2temperature has also been reported.