"Future developments in the control, functionalization and manipulation of magnetic nanoparticles and nanoscale magnetic devices require an understanding of collinear and non-collinear spin configurations and correlated changes of electronic structure on the sub-nanometer scale.In this project, an experimental methodology will be developed to allow magnetic spin structures in differently shaped nanomagnets to be visualized quantitatively and correlated with their crystallographic, compositional and defect structures. The project is based on the development of electron holography in the transmission electron microscope. It aims to provide quantitative measurements of internal magnetic fields in nanoparticles and devices that have characteristic dimensions of between 2 and 20 nm with a spatial resolution of better than 1 nm, both in projection and in three dimensions. Developments in instrumentation will allow the measurements to be acquired in situ in the electron microscope at elevated and reduced specimen temperatures and in the presence of oxidizing and reducing gases.The project is highly interdisciplinary, requiring close collaboration between scientists working on nanoparticle synthesis, device fabrication, magnetic modeling, computational mathematics and characterization techniques. It will provide a powerful new analytical tool at the frontiers of the highest spatial resolution analysis of spin and electronic structures that will have far-reaching impact beyond a specific research domain, not only in fundamental magnetism but also for applications that include magnetic recording, spintronics, catalysis and biomedical applications of magnetic nanoparticles.The methodology will also benefit European industry by providing a new leading edge in the fast growing international market of in situ transmission electron microscopy."