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Spin-wave measurements on MBE-grown zinc-blende structure MnTe by inelastic neutron scattering

2002; American Physical Society; Volume: 66; Issue: 22 Linguagem: Inglês

10.1103/physrevb.66.224426

1095-3795

B. Hennion, W. Szuszkiewicz, E. Dynowska, E. Janik, T. Wójtowicz,

Physics of Superconductivity and Magnetism

Spin-wave excitations of a MBE-grown single crystal of MnTe with a zinc-blende structure have been measured by inelastic neutron scattering in the type-III antiferromagnetic low-temperature phase of this compound. The experimental data have been modeled with a Heisenberg Hamiltonian including isotropic exchanges and magnetic anisotropy. Exchange constants and anisotropy terms have been estimated, which allowed a discussion on the relative importance of distant neighbors. The relevance of anisotropic exchanges is also discussed. The assumption of a collinear spin arrangement provides a consistent description of the spin-wave spectrum, including inelastic-neutron-scattering cross section. The temperature dependence of the spin waves revealed an anomalously strong damping, which starts well below the transition temperature.