Magnetic Effects in the Paraxial Regime of Elastic Electron Scattering

Abstract

Based on a recent claim [Phys. Rev. Lett. 116, 127203 (2016)] that electron vortex can be used to image magnetism at the nanoscale in elastic scattering experiments, using transmission electron microscopy, a comprehensive computational study is performed to study magnetic effects in the paraxial regime of elastic electron scattering in magnetic solids. Magnetic interactions from electron vortex beams, spin polarized electron beams and beams with phase aberrations are considered, as they pass through ferromagnetic FePt or antiferromagnetic LaMnAsO. The magnetic signals are obtained by comparing the intensity over a disk in the diffraction plane for beams with opposite angular momentum or aberrations. The strongest magnetic signals are obtained from vortex beams with large orbital angular momentum, where relative magnetic signals above $10^{-3}$ are indicated for $10\hslash$ orbital angular momentum, meaning that relative signals of one percent could be expected with the even larger orbital angular momenta, which have been produced in experimental setups. All results indicate that beams with low acceleration voltage and small convergence angles yield stronger magnetic signals, which is unfortunately problematic for the possibility of high spatial resolution imaging. Nevertheless, under atomic resolution conditions, relative magnetic signals in the order of $10^{-4}$ are demonstrated, corresponding to an increase with one order of magnitude compared to previous work.

References in corpus (5)

• Atomic scale electron vortices for nanoresearch
• Holographic generation of highly twisted electron beams
• A variable temperature study of the crystal and magnetic structures of the giant magnetoresistant materials LnMnAsO (Ln = La, Nd)
• Achieving atomic resolution magnetic dichroism by controlling the phase symmetry of an electron probe
• Scattering of electron vortex beams on a magnetic crystal: towards atomic resolution magnetic measurements

Cited by in corpus (8)

• Atomically sharp domain walls in an antiferromagnet
• Quantum-mechanical treatment of atomic resolution differential phase contrast imaging of magnetic materials
• Magnon diffuse scattering in scanning transmission electron microscopy
• Dynamical theory of angle-resolved electron energy loss and gain spectroscopies of phonons and magnons in transmission electron microscopy including multiple scattering effects
• Unveiling the impact of temperature on magnon diffuse scattering detection in the transmission electron microscope
• Electron vortex beams in non-uniform magnetic fields
• Simulations of magnetic Bragg scattering in transmission electron microscopy
• Electron Energy Loss Spectroscopy of oriented targets and magnetic transitions