Magnetoresistivity and Hall effect investigations under pressure on SmS

Abstract We report magnetoresistivity and Hall resistivity measurements on the black SmS. We observed positive magnetoresistance at low temperatures and negative magnetoresistance in a wide temperature range. The former seems to be ascribed to a magnetic field effect on impurity conduction, and the latter can be attributed to gap-energy reduction by magnetic fields. We also detected hysteresis in the T -dependence of the electrical resistivity under magnetic field.