Unit-cell dimensions of α-MnTe in the 295K – 1200K temperature range

Unit cell dimensions of high-quality MnTe crystals with NiAs structure were analyzed at temperatures ranging from 295 K to 1200 K. First, the X-ray diffraction were carried out on powdered sample at room temperature using the laboratory diffractometer. Next, the diffraction patterns in a wide temperature range were accumulated with the use of synchrotron radiation. The Rietveld refinement to all experimental data was applied. The average values of linear expansion coefficients in a and c direction are reported. The observed presence of MnTe2 impurity phase in the temperature range from about 500 K to 1050K is attributed to decomposition of a small fraction of MnTe during heating.