Nanogranular thin films of FexAg100-x (x=7,15,35) are an excellent system to study the interplay between the nanostructure and the magnetic behaviour, which is triggered by the strength of the different interactions (direct,RKKY and dipolar) among the magnetic nanoentities. At low concentrations we find a super spin glass behaviour, whereas for x around 35 a superferromagnetic state is settled. We have used a bunch of structural techniques (TEM, XRD, HAADF) which show the existence of nanoparticles. These nanoparticles affect clearly the magnetisation and resistivity responses measured between 2-300 K. However, the nanoparticle magnetic behaviour can only be defined and interpretated with SANS. For this purpose we ask for the application of a magnetic field using the capability of SANS2D with a H = 2 T magnet to extract the magnetic signal above and below the irreversibility temperature.