VOLUME 41, NUMBER 9 15 MARCH 1990-II g etoresistance and Hall effect near the metal-insulator tr 't'o «n-type Cdo 95Mno»TeThe magnetoresistance (MR) and Hall coefficient of n-type Cd095Mnp o5Te samples with carrier concentrations 1.2X 10"~n~6 .6X10"cm ' were measured at 1.2~T 4.2 K in fields up to 200 kOe. The results at zero magnetic field show that the carrier concentration at the metal-insulator transition is n, =-2X10" cm ', in rough agreement with Mott's prediction. In fields H 80 kOe the resistivity p first increases with H, then passes through a maximum, and finally decreases. The increase of p at low fields is accompanied by an increase in the magnitude of the Hall coefficient, while the decrease of p above the maximum is accompanied by an increase in the Hall mobility.The MR below -80 kOe is attributed to mechanisms associated with the giant spin splitting of the conduction band. The increase of p at low fields follows the behavior expected from quantum corrections to the conductivity arising from the electron-electron interaction. The decrease of p above the maximum is attributed to the rise of the Fermi energy in the majority-spin subband.Above -80 kOe the qualitative behavior of the MR depends on the carrier concentration. Samples with n & n, exhibit an upturn in the resistivity at high fields. This effect is attributed to the squeezing of the donor-electron wave function. In addition, the MR of these samples shows an anomaly near the first magnetization step. In metallic samples (n & n, ) the MR and Hall coefficient exhibit oscillations at high fields. The oscillations are interpreted as Shubnikovde Haas oscillations arising from the majority-spin subband. This interpretation is supported by model calculations.

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