Longitudinal magnetoresistance in silver and copper between 4.2 and 35 °K

Abstract

Longitudinal magnetoresistance has been measured in a number of single crystals of silver and one very pure single crystal of copper in fields up to 65 kG and at temperatures between 4.2 and 35 °K. The purpose of the work has been to investigate the effects of different types of electron scattering, in particular small angle scattering. It has been found that at 4.2 °K impure crystals obey the relaxation time approximation fairly well, whereas crystals that have been purified (by oxidation at 800 °C) do not. Above 4.2 °K, the addition of long wavelength phonons has caused the magnetoresistance to increase substantially, as predicted by Pippard (1964), but agreement with Pippard’s theory is only qualitative. To account for the results a more detailed treatment of the scattering is required.