Magnetoresistance and Hall effect in n-type indium antimonide in the magnetic freeze-out region

Measurements on n-type indium antimonide down to 0.3K are described of the resistivity in a magnetic field (0-40 kG) both parallel and perpendicular to the current, and of the Hall effect. Increases of resistivity by a factor of 10 10 are observed before the resistivity becomes too high to measure provided special care is taken over the preparation of the surface of the specimen. A saturation of resistivity with increase of magnetic field is sometimes observed and this is attributed to the effect of a conducting surface layer. The resistivity approximates to the form rho -1 = rho 01 -1 exp(-E 1 /kT)+ rho 03 -1 exp(-E 3 /kT). The E 1 region is identified with magnetic freeze-out and the E 3 region with electrons hopping between donor centres. Good agreement is obtained between theory and experiment for the magnetic field dependence of rho 03 .