Agglomeration and sintering in annealed FePt nanoparticle assemblies studied by small angle neutron scattering and x-ray diffraction

In this work we give a detailed account of the use of small angle neutron scattering to study the properties of polymer mediated, self assembled nanoparticle arrays as a function of annealing temperature. The results from neutron scattering are compared with those obtained from x-ray diffraction. Both techniques show that particle size increases with annealing temperatures of 580°C and above. They also show that the distribution of particle diameters is significant and increases with annealing temperature. The complementary nature of the two measurements allows a comprehensive structural model of the assemblies to be developed in terms of particle sintering and agglomeration. To realise the potential of nanoparticle assemblies as a monodispersed data storage medium the problem of particle separation necessary to avoid sintering and agglomeration during annealing must be addressed.