2D Ising-Like Ferromagnetic Behaviour for the Lamellar Cr 2 Si 2 Te 6 Compound: A Neutron Scattering Investigation

As far as we know, Cr 2 Si 2 Te 6 is the first compound exhibiting a quasi-2D Ising ferromagnetic behaviour ( T c = 32 K): elastic-neutron-scattering experiments on a single crystal and close examination of the thermal evolution of the order parameter led to the critical exponent β ≈ 0.17, comparable to the expected one for a 2D Ising model (β = 0.125); inelastic-neutron-scattering experiments allowed to determine two magnons dispersion curves with 2D Ising-like character. A third magnetic excitation branch has also been measured, for which a tentative explanation is given.