Magnetic properties of diluted magnetic semiconductor Hg_0.89Mn_0.11Te

The magnetization of Hg_0.89Mn_0.11Te single crystal grown by vertical Bridgman method was studied by using superconducting quantum interference device magnetometer (SQUID Magnetometer). First, magnetization measurements were done under various magnetic field strengths from -20 kOe to 20 kOe at 5 K, 15 K, and 77 K, respectively. Then, the magnetizations were measured with continuous changes of temperature in the range from 5 K to 300 K under the magnetic field of 0.1 kOe and 10 kOe, respectively. The modified Brillouin function was well fitted with the data of magnetization vs. magnetic field strength. The analysis indicated that there was an antiferromagnetic exchange coupling among Mn²⁺ ions. The results of reciprocal susceptibility vs. temperature fit Curie-Weiss law very well at the temperatures above 40 K, but deviate from the law from 5 K to 40 K, which shows that the antiferromagnetic exchange coupling among Mn²⁺ ions increases in the lower temperature range below 40 K. The experimental result was explained by extending higher-order terms in the calculation of susceptibility and fitted by a power law function. The measurements reveal that Hg_0.89Mn_0.11Te possesses paramagnetic properties at temperatures from 5 K to 300 K.