Spin-wave measurements on hexagonalMnTeofNiAs-type structure by inelastic neutron scattering

Abstract

MnTe with a hexagonal structure of NiAs type is an antiferromagnetic semiconductor below the Néel temperature T N = 310 K. The spin-wave excitations of a MnTe single crystal have been measured at T =11 K by inelastic neutron scattering. The experimental spin-wave dispersions, obtained along five high-symmetry directions of the reciprocal space, have been modeled with a Heisenberg Hamiltonian including isotropic exchanges up to the third nearest neighbors and a planar magnetic anisotropy. This yielded the exchange integral values J 1 = −21.5 K, J 2 = 0.67 K, and J 3 = −2.87 K. These results are presented and compared to experimental values of relevant diluted magnetic semiconductors, allowing a discussion on a generic description of the distance dependence of the nearest-neighbor magnetic interactions.

Phase separation and exchange biasing in the ferromagnetic IV-VI semiconductor Ge1−xMnxTe

“…3,8 Between x Mn = 60 to 90%, Ge 1−x Mn x Te is two-phase and exists in the cubic NaCl and hexagonal NiAs phase. 3,8 This is due to the different crystal structures of the alloy constituents, where GeTe is ferroelectric and crystallizes in a rhombohedrally distorted rock salt lattice 3 and bulk MnTe in the hexagonal NiAs structure 9 but can be also stabilized in the cubic zinc blende structure in epitaxial layers. 10 Both MnTe phases are antiferromagnetic ͑AFM͒ with Néel temperatures T N = 310 K and 65 K, respectively.…”

“…10 Both MnTe phases are antiferromagnetic ͑AFM͒ with Néel temperatures T N = 310 K and 65 K, respectively. 9,10 In this Letter, the structural and magnetic properties of Ge 1−x Mn x Te epilayers with Mn content close to the solubility limit are investigated. The samples were grown by MBE onto BaF 2 ͑111͒ substrates and the Mn content adjusted in the range of 45 to 55%.…”

Microhardness and the Young Modulus of Thin, MBE-Grown, (Sn,Mn)Te Layers Containing up to 8% of Mn

“…The lattice parameter value in the (Sn,Mn)Te solid solution decreases with an increase of Mn content but the mechanical properties of a hypothetical MnTe crystal with the rock-salt structure are not known. The MnTe crystallizes in the hexagonal structure of the NiAs type ( [13] and references therein), the metastable, zinc blende phase of this compound only can also be obtained by MBE (see, e.g., [14]). The observed qualitative composition dependence of the microhardness in (Sn,Mn)Te thin layers is similar to that observed in (Pb,Sn)Te bulk crystal [15] but differs significantly from that recently observed for several PbTe-based solid solutions containing Cd [16,17], Ge [18], or Ca [19].…”

Deterioration of Mechanical Properties of MBE-Grown, Metastable Semiconductor Layer with Time: the Case of Zinc Blende MnTe

“…The MnTe phase diagram can be found in [1]. The stable MnTe crystal phase exhibits a hexagonal structure of NiAs type ( [2,3] and references therein). The metastable MnTe phase crystallizes in the zinc blende structure, this form of crystal has been obtained for the first time in [4].…”