MAGNETIC FIELD ENHANCED BACKSCATTERING OF FOCUSED ELECTRONS IN MESOSCOPIC METALLIC BRIDGES

摘要

We have observed an increase in the longitudinal magnetoresistance of mesoscopic tungsten bridges at low temperatures. We propose this effect to be caused by backscattering of electrons through spiralling orbits with radius smaller than the film thickness. When tilting the field direction slightly away from the bridge-axis, additional surface scattering leads to an abrupt destruction of this backscattering.