Small-angle neutron scattering measurements with polarised neutrons on Fe-Ag magnetic granular systems

Different Fe-Ag magnetic granular samples have been prepared by changing the relative Fe volume concentration. The evolution of their morphology with iron concentration has been studied by small angle scattering measurements performed with polarised neutrons. The particles average size determined from nuclear scattering data is about 7 Å and it does not change with varying Fe content. On the other hand, the shapes of nuclear and magnetic scattering curves are different in the range of sizes corresponding to magnetic particles, indicating that similar structures display different magnetic behaviours. Finally, the analysis of polarised neutron data suggests the existence of Fe rich regions with negligible magnetisation.