A small-angle neutron scattering model for polydisperse spherical particles with diffusion zones and application to soft magnetic metallic glass

An analytical expression for the small-angle neutron scattering intensity o f diluted systems of polydisperse spherical particles, with diffusion zones , embedded in a matrix is presented. It is used within a nonlinear regressi on procedure to analyse small-angle neutron scattering experiments with pol arized neutrons on an Fe73.5Si15.5B7CuNb3 alloy. The results for the nuclea r and magnetic scattering length densities allow verification of the inhibi tor concept introduced for the explanation of the limited sizes of precipit ates developing during nanocrystallization. In the case of amorphous Fe73.5 Si15.5B7CuNb3 alloy, the observed nanocrystals of the Fe3Si type are surrou nded by an Nb-enriched shell, which stops the growth of the precipitates. W ith the results of polarized neutron scattering experiments, it is shown th at magnetic and nuclear small-angle neutron scattering signals have the sam e origin. Additionally, the precision of the fits is improved by complement ary use of polarized neutrons.