The magnetic properties of Iron-based Ferrites (AB2O4) are quite complex due to competing magnetic interactions between A2+ sites and B3+ sites. The magnetic properties are even more complex in milled nanoparticles, because milling promotes mixing of A and B site ions, and a shell of defective material forms around the core of the nanoparticle. Resultant magnetic phenomena, such as supermagnetism, show great potential as diagnostics and theranostic medical applications.Our research on nanostructured by ZnFe2O4 diffuse neutron scattering with polarisation analysis revealed weak ferrimagnetic order even at minute levels of inversion (< 1 %), that magnetic short range order stems from antiferromagnetic near neighbor coupling, and that magnetic relaxation extends to well above room temperature.This leads to a consistent picture on the interplay between ferromagnetic and antiferromagnetic long-range and short-range order. We now wish to perform PA-SANS experiments on D33 to probe1.the strength and length scale of ferromagnetic short range order2.the relative sizes the core and shell of the nanoparticles, and3.differences between the magnetic contribution of the core and shell