Anisotropy and large magnetoresistance in the narrow-gap semiconductorFeSb2

A study of the anisotropy in magnetic, transport, and magnetotransport properties of ${\mathrm{FeSb}}_{2}$ has been made on large single crystals grown from Sb flux. Magnetic susceptibility of ${\mathrm{FeSb}}_{2}$ shows diamagnetic to paramagnetic crossover around 100 K. Electrical transport along two axes is semiconducting, whereas the third axis exhibits a metal-semiconductor crossover at temperature ${T}_{\mathrm{cr}}$ which is sensitive to current alignment and ranges between 40 and 80 K. In $H=70\mathrm{kOe}$ semiconducting transport is restored for $T<300\mathrm{K},$ resulting in large magnetoresistance $[\ensuremath{\rho}(70\mathrm{kOe})\ensuremath{-}\ensuremath{\rho}(0)]/\ensuremath{\rho}(0)=2200%$ in the crossover temperature range.