INELASTIC NEUTRON SCATTERING IN γ-Mn(12%Ge) ALLOY ABOVE AND BELOW THE NEEL TEMPERATURE

摘要

The magnetic excitations different from spin waves in the γ-Mn(l2%Ge) antiferromagnet are the subject of the present investigation. The inelastic neutron scattering was measured at 4 temperatures above T_N . The Lorentz-ian-type formula for the inelastic neutron scattering cross-section with the spectral width for a hydrodynamic region was used for data analysis. The obtained values of the "stiffness constants" are of the order of 200 meV A and they depend weakly on temperature in the range of 1.04—1.25T_N. The inelastic neutron scattering for energy transfers below and close to the value of the gap energy of the spin wave spectrum was measured at room temperature. The observed intensities can be treated as a sum of intensities of neutrons scattered on spin waves around the magnetic Brillouin zone centre and those scattered on fluctuations at the zone boundary.