This proposal aims to investigate the short range structure and morphology of FePt NPs, of average diameter ~ 2 nm, and their surrounding surfactant layer (oleic acid and hexadecyl-amine) through Nimrod. FePt NPs are a diverse class of magnetic NPs which exhibit attractive properties for potential applications, from high density data storage devices to biomedical applications. Very few experimental investigations of this kind have been reported to date, this investigation aims to not only advance this field of research, but also enable the NPs physical properties to be enhanced and their ligand exchange ratios to be defined. We intend to take measurements of selected isotopic substitutions of NP colloidal solutions,with D/H-variants of the surfactants and solvent. We will define the structural properties through 2nd order difference measurements and Pair Distribution Functions analysis.