Neutron scattering study of structural and magnetic properties of hexagonal MnTe

Single crystals of hexagonal MnTe (in NiAs structure) have been grown by the physical vapour transport method and investigated by neutron scattering techniques. Lattice parameters and magnetic intensity of Bragg peaks characteristic of the antiferromagnetic order of the first kind have been measured by elastic neutron scattering in the temperature range from T = 10 K to the Neel temperature TN = 310 K. A smooth temperature dependence of the lattice parameter values a and c as well as of the c/a ratio has been found. A brief survey of phonon and magnon modes has been performed at room temperature by inelastic neutron scattering, yielding acoustic phonon branches along a* and c* directions at frequencies below 3 THz and the presence of the magnon mode, already strongly damped due to the vicinity of the magnetic phase transition. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)