Is magnetic chiral dichroism feasible with electron vortices?

TL;DR

This paper evaluates the potential of using electron vortex probes to detect magnetic transitions, finding that the dichroic signal is too weak to be observed in nanoparticles larger than about 1 nm.

Contribution

It provides a theoretical estimate of dichroic signal strength and experimentally confirms the limitations for detecting magnetic signals with electron vortices.

Findings

Dichroic signal is undetectable for nanoparticles >1 nm.

Theoretical estimates suggest low signal strength under realistic conditions.

Experimental results confirm the theoretical limitations.

Abstract

We discuss the feasibility of detecting magnetic transitions with focused electron vortex probes, suggested by selection rules for the magnetic quantum number. We theoretically estimate the dichroic signal strength in the L$_{2,3}$ edge of the ferromagnetic d metals. It is shown that under realistic conditions, the dichroic signal is undetectable for nanoparticles larger than ~1 nm. This is confirmed by a key experiment with nanometer sized vortices.