Paramagnetic Spin Fluctuations in an ${\mathrm{Fe}}_{65}$${\mathrm{Ni}}_{35}$ {{Invar}} Alloy

Polarized neutron scattering experiments have been performed on an Fe65Ni35 Invar alloy in the paramagnetic phase at T=1.25Tc. Constant-q spectra were fitted to simple Lorentzian functions and the q-dependence of the half-width $\Gamma$ was found to agree with that of the spin-diffusion model in the measured q range (0.1 A-19A-1). The amplitude of the spin fluctuation can be well described by the localized model with parameters which are deduced from the measured spin-wave dispersion at low temperature, the magnetization, and the uniform susceptibility. The model can be also applied satisfactorily to other itinerant metals such as Fe and Ni.     «

Polarized neutron scattering experiments have been performed on an Fe65Ni35 Invar alloy in the paramagnetic phase at T=1.25Tc. Constant-q spectra were fitted to simple Lorentzian functions and the q-dependence of the half-width $\Gamma$ was found to agree with that of the spin-diffusion model in the measured q range (0.1 A-19A-1). The amplitude of the spin fluctuation can be well described by the localized model with parameters which are deduced from the measured spin-wave dispersion at low temp...     »