Boundaries for efficient use of electron vortex beams to measure magnetic properties

Abstract

Development of experimental techniques for characterization of magnetic properties at high spatial resolution is essential for progress in miniaturization of magnetic devices, for example, in data storage media. Inelastic scattering of electron vortex beams (EVB) was recently reported to contain atom-specific magnetic information. We have developed a theoretical description of inelastic scattering of EVB on crystals and performed simulations for EVB of different diameters. We show that use of an EVB wider than an interatomic distance does not provide any advantage over an ordinary convergent beam without angular momentum. On the other hand, in the atomic resolution limit, electron energy loss spectra measured by EVB are strongly sensitive to the spin and orbital magnetic moments of studied matter, when channeling through or very close to the atomic columns. Our results demonstrate the boundaries for efficient use of EVB in measurement of magnetic properties.