Inelastic neutron scattering at the magnetic Brillouin zone boundary in antiferromagnetic Mn(13.7% Ni) alloy

This is the first systematic study of the spin excitations around the MBZ boundary points in -Mn alloy. The magnetic inelastic neutron scattering was measured in the antiferromagnetic Mn(13.7% Ni) alloy in a sample with unequal domain distribution in the temperature range 0.025 TN -1.15 TN . The evidence of the magnetic excitations around the MBZ boundary points equivalent to the MBZ centres in -Mn alloy is presented. At low temperatures these excitations differ from excitations observed around the MBZ centres; they are rather similar to excitations observed above TN . When the temperature increases up to TN the excitations observed around MBZ centres become more similar to those around the MBZ boundary equivalent points. The results of the analysis are consistent with the general features of spin fluctuations.