EuTe. II. Resistivity and Hall Effect

The resistivity and Hall effect in n-type EuTe single crystals containing {~} 10¹⁹ carriers/cm³ were studied at $1.6<T<300$ K in magnetic fields up to 140 kOe. At temperatures T2TN, where TN9.7 K is the N\'eel temperature, the resistivity ρ at $H=0$ increased rapidly with decreasing T. This increase in ρ was removed entirely by the application of a high magnetic field H. At 14.5 K, ρ decreased gradually with increasing H. Hall measurements showed that the negative magnetoresistance at 14.5 K was due almost entirely to an increase in the mobility, and not to an increase in the number of charge carriers. At liquid-helium temperatures, ρ(H) exhibited different behaviors in three different ranges of the field H: (i) At 0≤H10³ Oe, ρ decreased very rapidly with H, with the result that ρ (1 kOe) was at least one order of magnitude smaller than ρ(0); (ii) in the canted phase (1H70 kOe), ρ decreased slowly with increasing H; (iii) in the paramagnetic phase (H70 kOe), ρ was nearly field independent. Hall measurements showed that the negative magnetoresistance in the canted phase was largely due to an increase in the mobility, and not to an increase in the carrier concentration. At the canted-to-paramagnetic transition, ∂ρ∂H and ∂ρ∂T changed abruptly. These changes in the derivatives of ρ were used to determine the canted-to-paramagnetic phase boundary Hc(T).