Scattering of electron vortex beams on a magnetic crystal: Towards atomic-resolution magnetic measurements
2014 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 89, no 13, 134428- p.Article in journal (Refereed) Published
Use of electron vortex beams (EVB), that is, convergent electron beams carrying an orbital angular momentum (OAM), is a novel development in the field of transmission electron microscopy. They should allow measurement of element-specific magnetic properties of thin crystals using electron magnetic circular dichroism (EMCD)-a phenomenon similar to the x-ray magnetic circular dichroism. Recently, it has been shown computationally that EVBs can detect magnetic signal in a scanning mode only at atomic resolution. In this follow-up work, we explore in detail the elastic and inelastic scattering properties of EVBs on crystals, as a function of beam diameter, initial OAM, acceleration voltage, and beam displacement from an atomic column. We suggest that for a 10-nm layer of bcc iron oriented along (001) zone axis, an optimal configuration for a detection of EMCD is an EVB with OAM of 1 (h) over bar and a full width at half maximum diffraction-limited beam diameter of 1.6 angstrom, acceleration voltage 200 kV, and an annular detector with inner and outer radii of 7 and 44 mrad, respectively.
Place, publisher, year, edition, pages
2014. Vol. 89, no 13, 134428- p.
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:uu:diva-227279DOI: 10.1103/PhysRevB.89.134428ISI: 000335791000002OAI: oai:DiVA.org:uu-227279DiVA: diva2:730835