Magnetoresistance in Heavily Doped n-Type Germanium

Abstract

The magnetoresistance of n-type germanium has been measured at 300°K, 77°K and 4.2°K with donor concentration in the range 10¹⁷ cm⁻³ to 2×10¹⁹ cm⁻³. The magnetoresistance symmetry relation is obeyed in all measured samples at 300°K within the experimental error. The measurement at 77°K shows definite deviation from the symmetry relation in samples with high donor concentration. The behavior of resistance change under the magnetic field at 4.2°K depends on whether donor concentration lies in impurity conduction range or in metallic conduction range. In metallic conduction range the observed magnetoresistance Δρ⁄ρ has been separated in to two components, one being positive and proportional to the square of magnetic field and the other being negative and showing saturation at a relatively low magnetic field. The former has been compared with the magnetoresistance observed at 77°K.