The exceptionally high carrier mobilities found in zero-gap ${\mathrm{Hg}}_{1-x}{\mathrm{Cd}}_x\mathrm{Te}$ $(x\approx 0.10)$ give rise to giant magnetoresistance (GMR). A two-carrier, high-field model provides a good description of the magnetoresistance and Hall effect at temperatures $6<T<\mathrm{}300\mathrm{}$ K and magnetic fields up to $H=10\mathrm{}$ T. The high-field data have a significant influence on the interpretation of the low-field results, in particular revealing the presence of acceptors despite the fact that the low-field Hall coefficient is negative. Surprisingly, at low fields the curvature of the GMR, $d^2{R/dH}^2$, is larger than that expected by up to a factor 30. The enhancement of the GMR makes ${\mathrm{Hg}}_{1-x}{\mathrm{Cd}}_x\mathrm{Te}$ potentially useful for read-head devices for magnetic media.

• Received 8 January 1998

DOI:https://doi.org/10.1103/PhysRevB.57.12239