The generalised susceptibility of FCC Mn(38%Ni) alloy

Anisotropy of the Neutron Scattering in the Paramagnetic Phase and on the Spin Waves in the Mn0.71Ni0.29Alloy

“…The obtained energy-gap value is E g = 3.0 ± 0.04 meV for 293 K and E g = 4.4 ± 0.2 meV for 15 K. The E g values are similar to those found for Mn 0.62 Ni 0.38 [2] and Mn 0.73 Ni 0.27 [6] indicating that the E g is independent of the alloy concentration in the range (0.27-0.38 Ni), which is in contrast to its strong dependence in the region of the fct-fcc transition [5,8].…”

“…The SW velocity obtained from data for 18 meV is: v = 19 ± 1 meV nm and v ⊥ = 16 ± 1 meV nm for 15 K; and v = 14 ± 1 meV nm and v ⊥ = 10 ± 1 meV nm for 293 K. Spin-wave damping factors are Γ = 5±2 meV nm and Γ ⊥ = 5 ± 1 meV nm at 15 K and are small compared to those for Mn 0.62 Ni 0.38 alloy [2] at this temperature.…”

“…There are 3 anisotropy axes in the system, each parallel to one of the (100)-type directions, as described in [2]. No significant anisotropy of the SW scattering was found in any other manganese-rich antiferromagnetic alloys with fcc or tetragonal structure.…”

“…The earlier study of the fcc Mn 0.62 Ni 0.38 revealed the pronounced uniaxial anisotropy both in the static and dynamical part of the generalised susceptibility [1,2]. There are 3 anisotropy axes in the system, each parallel to one of the (100)-type directions, as described in [2].…”

“…Another specific feature of the spin-waves in the fcc Mn-Ni alloys is their heavy damping observed in the Mn 0.73 Ni 0.27 [6] at room temperature and in the Mn 0.62 Ni 0.38 [2] even at 13 K (far below T N = 401 K).…”