Characterization of HgMnTe crystals grown by vertical Bridgman method

Single crystals of Hg_0.89Mn_0.11Te have been successfully grown by vertical Bridgman method at the optimized growth conditions. The X-ray rocking curve shows that the as-grown Hg_1-xMn_xTe possesses high perfection. Hall measurement data suggest that the electronic properties of as-grown wafers satisfy the requirement of detector manufacture. The resistivity and magnetization of the crystal were also measured by the superconducting quantum interference device (SQUID) magnetometer in the temperature ranges 5-80 and 5-300 K, respectively. The applied magnetic fields were 8.0×10⁵, 1.6×10⁶, 3.2×10⁶, and 5.2×10⁶ A m^-1 for the resistivity measurements, and 8.0×10³ A m^-1 for magnetization measurement. The results of reciprocal susceptibility versus temperature fit Curie-Weiss law very well at the temperatures above 40 K, but deviate from the law in the range 5-40 K, which shows that the crystal possesses paramagnetic properties in the temperature range, and the paramagnetism of the crystal enhances in the lower temperature range below 40 K. The resistivity decreases with an increase of applied magnetic field in the extrinsic conduction region (T>20 K) due to the decrease of the ionization energy ε_1. In the hopping conduction region (T<20 K), the increased spatial extent of the acceptor wave function under magnetic field leads to impurity conduction, therefore, the difference of resistivity under different magnetic fields increases rapidly with decreasing temperature, and the difference of that under zero magnetic field and 5.2×10⁶ A m^-1 is more than 3 orders of magnitude at 5 K.